FCC Chairman Warns of Wireless Spectrum Gap

locallyunscene writes "'We are fast entering a world where mass-market mobile devices consume thousands of megabytes each month,' FCC Chairman Julius Genachowski warned at CTIA Wireless yesterday. 'So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is? What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks?'"

Comments

Surrogates

[Anonymous Coward]

This is the just one of reasons Surrogates is so absurd.

It's 1996 again?

[chicago_scott]

This sounds like back in the mid-1990's when people were giving dire prediction about the Internet being overloaded and becoming unusable.

The more things change the more they stay the same.

Re:It's 1996 again?

[snowraver1]

The difference is that the internet is more scalable. We didn't run into problems back then because of increases in CPU power that allows for larger routing tables and advances in fibre that allows for more data on the same strand. This is a physical problem. There is only so much spectrum available. Once the air is saturated on the allocated frequencies, we are done. No more room, period.

Re:It's 1996 again?

[TikiTDO]

Spot on. The problem with the article is that it fails to account for advances in technology. As we need more bandwidth, technology will evolve to give you more bandwidth. That in less spectrum, with higher reliability and less interference.

As you pointed out, this happened for wired connections in the past. In response, we are almost to commercial 40Gb and even 100Gb links, the latter being targeted for 40km stretches.

Re:It's 1996 again?

[Nikker]

Don't worry about the physical bandwidth as it will open the door to more ideas like distributed caching and broadcasting single packets among multiple devices. Then again the more people cry about the sky falling the more incentive there is to impliment ideas like this for way too much money to satisfy egos. Wireless is really the way to go for the end consumer and if it does really get that big then cell carriers will devote their towers into the mix(for a price of course). Remember it's not all the bandwidth that's being eaten up it's just this particular portion as demand goes up so eventually will the supply, we will just come up with more effective and clever ways of doing it.

Re:It's 1996 again?

[commodore64_love]

>>>Once the air is saturated on the allocated frequencies, we are done

Not quite "done". We can say goodbye to over-the-air FM and TV. We already lost channels 52 to 83 that were turned-over to cellphones, and I suspect it's only a matter of time until channels 2 to 51 (including the FM band) disappear. That would not meet the FCC's "30 fold" estimate, but it would increase the available wireless spectrum by about 9 times present levels.

Lower frequency shortwave and AM radio will probably survive, simply because it's not practical to carry-around 100 foot long transmitting antennas with your phone.

Re:It's 1996 again?

[randy of the redwood]

I think GP is probably correct. When we have problems, we tend to find solutions to them. Certainly with today's approach we are going to run out of bandwidth. Perhaps tomorrow's technology will stop sending signals in every direction, but somehow negotiate direct paths over the air using directed antennae from one or both transceivers. Then the 3D space starts becoming your friend instead of your enemy.

Re:It's 1996 again?

[rescendent]

We could start using Ultrawide band and just our data rates, while decreasing power needs and interference? http://en.wikipedia.org/wiki/Ultra-wideband

Re:It's 1996 again?

[commodore64_love]

>>>technology will evolve to give you more bandwidth.

No. There's a limit to how much technology can do. That's why phone lines are maxed-out at 56 kbit/s - there's no more room for expansion since it's already at the physical limit. Same applies with wireless.

Re:It's 1996 again?

[kevinmenzel]

DSL isn't over phone lines?

Re:It's 1996 again?

[TikiTDO]

DSL users faeries on pixie dust. You really should keep up with these things.

Re:It's 1996 again?

[jonbryce]

I'm getting about 7 Gbits from the phone line that used to be maxed out at 52k or so, and I can make voice calls on it at the same time as my downloads, something I couldn't do before.

Re:It's 1996 again?

[TikiTDO]

I think kevinmenzel illustrated the point quite well. Analog phone lines are indeed no faster than 56 kbits/second. That's why we went to a new technology, and now have DSL. However, I'm not proposing we try to get more data into current wireless protocols, clearly that is a waste of time as they were not designed to do this.

Physically though, the spectrum is effectively infinite. With technology advanced and sensitive enough, you could send all the world's data in a second, using the same spectrum that might now carry 10 bytes. Obviously, that might never even happen, but it is not wise to completely discount it.

Re:It's 1996 again?

[Anonymous Coward]

How about harmonics, sidechannels, and other data compression gimmicks that allow the military to beam encrypted voice and data over a brick? Or even multichannel skipping, packets fragmented and burst transmitted over any available frequency to be reassembled?

Or an increase in the discrimination of signal to noise ration, and the infinite slices of an individual Mhz?

This post also ignores that there will never come a time when everyone is using multiple devices, small matters like population density and the simultaneous number of active sets... in short, no one will ever be using their device at exactly the same time for the same duration. In the same geographically covered area, there may be a high number of users, yes... but will there ever be enough to saturate every single wireless tower?

Especially once I'm offered a discount on my slave contract for allowing a small tower to be placed on my forehead.

Re:It's 1996 again?

[TikiTDO]

Ooh, so many new terms to look up. This promises to be enlightening.

Though you would need to negotiate your slave contract discounts with your authorized, killer-robot-overlord happiness allocation unit.

Re:It's 1996 again?

[Anonymous Coward]

Simple solution. The US will simply have to buy back the spectrum it stupidly sold in auctions to companies, at a hundred times the selling price. Errr, maybe we don't have the money left anymore, having spent it on Iraq and Afghanistan, bailing out bankers and investment companies, and cash for clunkers...

Re:It's 1996 again?

[fbjon]

I'm pretty sure you're not using the phone line, but rather the cable that the phone line also happens to use. Ordinary phone lines max out at 56k, because the whole infrastructure of voice calls is designed with that limitation in mind.

Re:It's 1996 again?

[chicago_scott]

Analog phone lines are indeed no faster than 56 kbits/second

For the sake of clarity analog phone lines are inherently limited to 2400 bits/second (bps). Better compression algorithms got us up to 56 kbps.

Re:It's 1996 again?

[snowraver1]

"Allocated frequencies" were key words. Yes, there are lots of other frequencies that we could use, some better than others. The problem is that they are not currently licensed for that purpose, so cannot be counted as available bandwidth.

Re:It's 1996 again?

[chicago_scott]

Sorry for the repost, I meant to add this link explaining twisted pair:

http://www.computing.dcu.ie/~humphrys/Notes/Networks/physical.phone.html

Re:It's 1996 again?

[rohan972]

I'm pretty sure you're not using the phone line, but rather the cable that the phone line also happens to use.

Same line, different signal.

Re:It's 1996 again?

[snowraver1]

7 Gbits!?!? WOW, who is your provider? Do you live in the local exchange? If, so, that would definitely explain how you can make calls at the same time...

Re:It's 1996 again?

[commodore64_love]

No DSL is *not* over telephone lines. POTS (plain old telephone service) is defined as having a 0 to 8000 hertz bandwidth, hence the 56k dialup limit. The engineers have squeezed as much data as they can into that limited range.

DSL disconnects the POTS line, and replaces it with a central box (DSLAM) that converts the incoming twisted-pair and passes it along to higher-quality fiber or coax.

BTW thanks for modding me "troll" kevinmenzel.
-1 I disagree is not why moderation exists.

Re:It's 1996 again?

[blitziod]

you mena the phone line that used to be maxed out at 1200bps, then 2400 bps, then they KNEW that 9600 bps was the max ..there was JUST no way to send any more information down a single phone line. Then they KNEW 56000 bps was the max, etc..

Re:It's 1996 again?

[commodore64_love]

>>>I'm getting about 7 Gbits from the phone line that used to be maxed out at 52k or so

No you're not. When you upgraded to DSL, the company disconnected the telephone line (bandlimited to 4000 hertz) with a standard twisted-pair wire (no upper limit). Furthermore they disconnected your house from the old phone service, and connected it to a DSLAM which converts the short ~500 meter cable to higher-quality coaxial or fiber.

So my previous comment about the 4000-hertz wide telephone service still being limited to just 56k is still true.

Re:It's 1996 again?

[commodore64_love]

Correction: Replace "8000 hertz" with "4000 hertz"

Re:It's 1996 again?

[spinkham]

So you're saying it wasn't a physical limitation of the broadcast medium at all, it was a hardware limitation of the receiver.

Re:It's 1996 again?

[fluffy99]

Yes it is using the same physical lines (although they may have to be cleaned up to remove loading coils or branched circuits). As you pointed out though, it not the same equipment at either end. Also, calling it an 8000 hertz bandwidth is rather misleading. It's an 8-bit sample taken at a sampling rate of 8000 hertz, not an 8k wide frequency range as your wording might imply. Its the sampling rate time the sample size that gives you a theoretical 64-kilobit/second limit, but other FCC and technical issues such as the typical robbed bit signaling end up dropping the max to 56k.

Typically, the DSLAM at the wiring closet or CO is connected via fiber to the rest of the infrastructure.

Re:It's 1996 again?

[commodore64_love]

>>>Same line, different signal.

No... same line, different bandwidth. The bandwidth is the key. 4000 hertz for the phone dialup modem versus ~200,000 hertz for the DSL connection. If the DSL was forced to limit itself to the same bandwidth as a dialup modem, it would only be 64k. (This is called a "DSzero" or "DS0" line by the telephone company, also called ISDN.)

DSL also terminates your line only a few hundred feet from your house, and upgrades it to fiber or coax, whereas the original telephone line could travel many miles with no apparent degradation of the 4000-hertz-wide signal.

Re:It's 1996 again?

[icebike]

This is a physical problem. There is only so much spectrum available.

Kind of reminds me of the predictions that 9.6, then 14.4, then 28.8 were the fastest possible modem throughput on copper because it was physically impossible to squeeze any more information onto the available bandwidth.

Yet each time someone makes this assertion something else comes along.

With radio, as frequencies increase, building penetration, foliage penetration decreases. With increased cellular handset density the signal to noise floor rises and soon the phones can't hear themselves for all the shouting they have to do to be heard.

This is why the 700Mhz band was so important to wireless applications. Freeing this from television allows use in applications where range and penetration are important, such as cell phones and urban wifi.

Alowing cellular phones to add ranges in the 700Mhz band to the work-horse 850 and 900 bands allows broader coverage with the same towers, and increased building penetration.

Similarly, newer encoding schemes (the way modem speeds were enhanced) will allow faster service in the same bandwidth, or the same service in narrower bandwidth. Some say that the the encoding schemes in GSM are over due for enhancement anyway.

Additionally, different employment strategies can free up a lot of bandwidth over a urban area. We are starting to see many carriers deploying Femtocells, low power wifi and 3G stations that feed direct to the internet, and are no bigger than a book. If deployed widely, you could have a low power cell "tower" on top of a utility pole at every intersection, each with a range of a city block.

That solves a multitude of problems, not the least of which is suppressing the transmit power of every cell phone in range, which greatly improves the signal to noise ratio. There is probably no reason to ever build a cell tower in urban areas.

Lets not predict the end of time just yet.

Re:It's 1996 again?

[fluffy99]

Analog phone lines are indeed no faster than 56 kbits/second

For the sake of clarity analog phone lines are inherently limited to 2400 bits/second (bps). Better compression algorithms got us up to 56 kbps.

For the sake of clarity, you don't know what the fuck you're talking about. 56-kbits/second is the max because that's what the analog-digital converters within the telco are set for. A DS0 phone circuit is by definition a 56k or 64k digital channel (depends on inband or out-of-band signalling). The early 2400 and 4800 limits were due to poor quality lines and equipment that just wasn't setup to go faster. This was back when most users were just doing text and fax machines were the bandwidth intensive applications.

The magic of 56k comes from the users modem being able to synchronize its timing and discrete output levels (the "constellation") to match the analog-digital converter attached to the users phone line. The server end of the circuit must be digitally connected for this to work.

Re:It's 1996 again?

[icebike]

What are you talking about "Buy it back"?

These companies are using this bandwidth to provide the services we need. Ever heard of a Cell phone?

The government has no need of this specturm. WE the PEOPLE do.

Buy it back from ATT and your cell phone is off the air.
In your case this may lead to considerable signal to noise ration improvement. But in the general case its a silly suggestion.

Re:It's 1996 again?

[commodore64_love]

>>>I think kevinmenzel illustrated the point quite well. Analog phone lines are indeed no faster than 56 kbits/second. That's why we went to a new technology, and now have DSL.
>>>

Yes but if DSL was forced to fit inside the same bandwidth as the old dialup phone modems (4000 hertz wide), it would still only be 64 kbit/s speed. *That* was the point I was making... you can only squeeze so much data into a FIXED width of space. The universe places physical limits in what engineers can do.

Another example is Digital AM Radio, which is limited to just 4500 hertz in Europe, or ~20 kbit/s.

Re:It's 1996 again?

[commodore64_love]

>>>phone lines are inherently limited to 2400 bits/second (bps). Better compression algorithms got us up to 56 kbps.
>>>

False. The physical limits on an analog phone line are 3,429 SYMBOLS per second, with approximately 10 bits represented by each symbol, to achieve 33,800 bits per second (V.34)

The physical limits on digital phone lines are 8000 SAMPLES per second, and 7 bits each, to yield 56,000 bits per second. The 8th bit is reserved by the telephone company, otherwise we would see 64000 bit/s.

Using V.92 data compression, you can achieve an *apparent* speed of ~400 kbit/s for text, ~150 for executables, and ~56k for incompressible JPGs, GIFs, and other datafiles.

Re:It's 1996 again?

[commodore64_love]

>>>Then they KNEW 56000 bps was the max, etc..

Ever heard of the Shannon limit? On an analog phone line, you cannot exceed 35 kbit/s (V.34). Ever heard of Nyquist theory? On a digital phone line, the 4000 hertz bandwidth sampled at 8000 times per second, times 7 bits per sample == 56000 maximum.

As Scotty on Star Trek would say, "You cannae change the laws of physics!"

Re:It's 1996 again?

[negRo_slim]

These companies are using this bandwidth to provide the services we need. Ever heard of a Cell phone?

I disagree with the fact "we need" cell phone service.

Re:It's 1996 again?

[Idiomatick]

I thought of a solution.

Have cell towers and data towers be much much closer together. Then have them all be short range. And transfer the data over cables. Done, If we make 30x as many towers (these would all be tiny cheap places compared to current towers) and made more fiber hookups... Then the problem is solved without anything particularly genius. We can probably keep doing this for quite some time before it becomes a major issue.

Re:It's 1996 again?

[tweak13]

No DSL is *not* over telephone lines. POTS (plain old telephone service) is defined as having a 0 to 8000 hertz bandwidth, hence the 56k dialup limit. The engineers have squeezed as much data as they can into that limited range.

Actually that limit is digital in nature, and has nothing to do with the quality (or lack thereof) in the lines themselves. I work at a university and we use phone lines to move audio from building to building. It's analog the whole way, with all switching equipment removed and everything hard wired together at the university's telecom office. It's good enough to get FM broadcast quality even running all the way across campus and back again.

Re:It's 1996 again?

[commodore64_love]

I meant to say "4000 hertz" not 8000 hertz. Ooops.
.

>>>is using the same physical lines (although they may have to be cleaned up to remove loading coils or branched circuits)

Yes but the whole point of this discussion is your have a *fixed* bandwidth or spectrum. If DSL was forced to fit inside the same 4000-hertz-wide telephone line as a dialup modem, it would be no faster than 56k (7 bits timed 8000 samples/second with bit 8 reserved).

If it were possible to exceed 56k over POTS, someone would have already done it.

Re:It's 1996 again?

[commodore64_love]

>>>technology will evolve to give you more bandwidth.

People didn't like my 56k/4000-hertz-wide telephone example, so I'll try a different tactic: Bandwidth is FIXED. You can change the datarate inside that fixed bandwidth, but that is limited by Shannon's Limit (analog) and Nyquist's Theorem (digital). Engineers can not violate the physical maximums placed upon us by the universe.

Re:It's 1996 again?

[ag0ny]

... because it's not practical to carry-around 100 foot long transmitting antennas with your phone.

Why not?

Re:It's 1996 again?

[commodore64_love]

>>>So you're saying it wasn't a physical limitation of the broadcast medium at all, it was a hardware limitation of the receiver.

No it was an EXAMPLE to illustrate what happens when bandwidth is limited. Imagine that every cellphone user is assigned 4000 hertz of space for his usage. How much data can be sent over that width? The answer is not "as much as we want". The answer is defined by the physical limits of the universe.

In the world of telephone modems 4000 hertz hits that universal maximum at just 56k. In the world of Digital AM radio, it's a mere 20k. QED the comment "technology will evolve to give you more bandwidth" is flat wrong because bandwidth is a fixed quantity, and how much information you can send in that fixed width is limited by the universe.

(And I really wish people would stop modding me "troll" when I am trying to EDUCATE you. No wonder my old Physics professor is sick of teaching - the students don't listen, he said.)

Re:It's 1996 again?

[Rich0]

You don't need nearly as long an antenna to receive an AM signal (granted, I still suspect they're a bit big for pocket-sized phones). If you allowed that the phone could transmit in one band in receive in another then the AM bands could still be useful.

Re:It's 1996 again?

[commodore64_love]

>>>I work at a university and we use phone lines to move audio from building to building.

Since telephone lines are bandlimited to 4000 hertz, what you are claiming is impossible. You would have to remove that 4000 hertz limit to carry the full 20,000 hertz audio spectrum, at which point the lines cease to be telephone wires...... they no longer meet the international specifications for POTS.

What you have is twisted-pair copper. Basically ethernet, but carrying analog audio instead of data.

Re:It's 1996 again?

[commodore64_love]

>>>>>>>>technology will evolve to give you more bandwidth.
>>
>>No. There's a limit to how much technology can do. That's why phone lines are maxed-out at 56 kbit/s - there's no more room for expansion since it's already at the physical limit (4000 hertz).

(Score:0, Troll)

Unbelievable. The moderators on this forum would fail basic PHYSICS 101. They can't even understand the simplicity of Shannon's Limit or Nyquist's Theorem (which state a limited bandwidth has a maximum data rate).

Re:It's 1996 again?

[Anonymous Coward]

Uh no. Pretty much all landline telephones are already digital, DSL just expands the bandwidth to levels greater than 4khz, His old phone service was likely switched from analog to digital about 10 years ago.

Your 4000-hz wide telephone service is still 4000-hz wide, but is digitized and resides in part of the full DSL spectrum. The phone company just charges you extra money to access the rest of the spectrum.

Re:It's 1996 again?

[TikiTDO]

But as fluffy99 just pointed out, this is not even a remotely valid comparison to make. Phone signal used all of the bandwidth in a rather wide range, in probably the most inefficient way possible. Even if DSL operated in the 0-4000 Hz range, it would use the spectrum much more efficiently than would an analog signal sampled at n times a second.

The idea I'm trying to get across is that technology is not limited to the techniques you are familiar with. So if we were limited to using the phone line as it has always been used, by sampling at fixed intervals, you would be absolutely correct. However, if an engineer was given the challenge to use the 0-4kHz range to transmit the most data possible, I assure you that the number would be much higher. Obviously, unlike you suggest near the end of your post, there is absolutely no reason to exceed 56k for this range. To do so would mean a return to the days of having to chose whether you want a telephone, or internet. Current technology is already beyond that. Also, even if someone did take up this challenge, the goal would not be to use POTS, which as you pointed out has certain limitations, but instead to use the 0-4kHz frequency to maximum efficiency, which would likely involve some entirely new data transfer methodology.

In other words, to spend time on increasing the speed of modems would be akin to modding a Model-T to go 100mph. I'm sure if you're dedicated enough, you could do it, but you could also go to a dealer and buy a car that does the same for 1/100th the cost.

I suggest you head over to Wikipedia and read up on some of the terms mentioned by the AC near the end of the thread. It explain what we're all trying to convey in a lot more technical detail.

Re:It's 1996 again?

[S1ngularity]

I am not an engineer, but couldn't you bundle a bunch of phone lines together to increase speed? And could something be somewhat simulated with a massive MIMO antennae array, especially with aforementioned ubiquitous somewhat directional femtocells?

Re:It's 1996 again?

[commodore64_love]

>>>I thought of a solution. Have cell towers and data towers be much much closer together

Heck just give everyone a cell tower, right on top of their roof. And then run the cable from each tower, through the owner's home, and out to the street....... wait a minute! That's just like wiring everyone directly. You don't need wireless.

Re:It's 1996 again?

[Anonymous Coward]

The problem with the article is that it fails to account for advances in technology. As we need more bandwidth, technology will evolve to give you more bandwidth.

Well, yes and no. There are physical laws here. You can't transfer more than the Shannon limit. But the problem is more politics and business than technology. The problem isn't a lack of spectrum, it's a lack of unlicensed spectrum. The cellular network as it exists is an anachronism. There is no reason voice and data should be distinguished the way they are, or for that matter why the phone company should be in control of the spectrum in urban areas.

You should get (preferably municipal) fiber into your building, install a wireless access point and have everyone's wireless devices talk to the Internet through the wireless access point. If you ever run out of spectrum you install more access points that each use lower power. A standard could exist for access points and devices to adjust their power levels the closer the device is to the access point, so that each device only uses as much power as is necessary to reach the closest access point and thus adding access points reduces power levels and allows a higher device density.

In rural areas you can just do what they do now and spectrum scarcity isn't a problem because of the low population density.

Re:It's 1996 again?

[countertrolling]

There's a limit to how much technology can do.

We can always pray...

Re:It's 1996 again?

[commodore64_love]

>>>I disagree with the fact "we need" cell phone service.

Me too. I have a prepaid cellphone that automatically adds $5 each month. It's now over $100 since I rarely use it. One of these days I'll go on a vacation and make lots of long-distance calls, but for now the money just keeps accumulating.

Re:It's 1996 again?

[PayPaI]

You mean like a shotgun modem?

Re:It's 1996 again?

[countertrolling]

If DSL was forced to fit inside the same 4000-hertz-wide telephone line as a dialup modem, it would be no faster than 56k...

Ah, so that's why my torrents are only 5Kb/sec down...

If it were profitable to exceed 56k over POTS, someone would have already done it.

Always happy to help...

Re:It's 1996 again?

[commodore64_love]

>>>Kind of reminds me of the predictions that 9.6, then 14.4, then 28.8 were the fastest possible modem throughput on copper because it was physically impossible to squeeze any more information onto the available bandwidth. Yet each time someone makes this assertion something else comes along.
>>>

False history. There were three speed limits - one was due to lack of knowledge, and the other two were imposed by the universe:

14k - based upon QAM with 4 bits per symbol - engineers didn't know any other method of modulation and believed this was the maximum they could do. Once they discovered trellis modulation, they realized they could reach the Shannon Limit:
35k - analog limit per Shannon's Theorem
56k - digital limit per Nyquist

Note that the last limit has stood for 15 years and will never be broken, unless we discover some alternate universe with different laws. In *this* universe the limit has been hit.

Re:It's 1996 again?

[MichaelSmith]

Smaller cells in busy areas. Land lines to connect cells. Sounds perfectly scalable to me.

Re:It's 1996 again?

[Anonymous Coward]

"... simply because it's not practical to carry-around 100 foot long transmitting antennas with your phone." [Citation required]

Re:It's 1996 again?

[commodore64_love]

>>>Phone signal used all of the bandwidth in a rather wide range

4000 hertz is not wide. Your compact disc player has more width (20,000).

>>>Even if DSL operated in the 0-4000 Hz range, it would use the spectrum much more efficiently than would an analog signal sampled at n times a second.
>>>

56k modems are not analog; they are digital. (33k modems are analog.) If DSL was confined to 4000 hertz like your 56k digital dialup modem, it would still be limited to the same 7 bits * 4000 hertz * 2 == 56000 bits/second.

>>>technology is not limited to the techniques you are familiar with.

No it's limited by the universe. Just as you cannot exceed 186,000 miles per second, neither can you exceed a certain datarate within a fixed width. You would understand my point if you had bothered to read your PHYSICS 101 textbook about Shannon's Limit or Nyquist's Theorem. Or as Scotty would say, "You cannae change the laws of da universe!"

Re:It's 1996 again?

[NetNed]

Well considering the actual cost per kb that any mobile provider charges, I can pretty much say with certainty that it will be a hurdle that will be overcome. With the going rates for data from any wireless provider, they would sell their first born to keep that over charging cash cow going.

Re:It's 1996 again?

[commodore64_love]

>>>Uh no. Pretty much all landline telephones are already digital

Dear Anonymous Coward: You committed a STRAWMAN ARGUMENT. Nowhere in my message did I say phonelines or 56k modems were not digital. I am well aware that modern phones are almost-universally digital in nature.

Re:It's 1996 again?

[rcpitt]

And this is the whole point - higher frequencies (they're commercializing 60GHz now - back when I first encountered it, it was bleeding edge and 90GHz was not even on the radar)

multi-GHz spectrum, micro-cells, spread-spectrum and software radios will make the problem domain shrink to the point where there simply isn't a problem. Today's traffic will be tomorrow's noise floor.

Re:It's 1996 again?

[commodore64_love]

http://www.computing.dcu.ie/~humphrys/Notes/Networks/physical.phone.html "Basic speed 2400 bps. Clever coding used to get up to 56 kbps. The last mile is (usually) analog."

Whatever professor is teaching this curriculum should be shot. Telephone lines were upgraded to digital almost twenty years ago. And the speeds can range from 110 symbols per second upto 3429 symbols per second (analog). Or 110 bit/s upto approximately 34000 bit/s (analog).

Here read this list of speeds for better understanding:
http://en.wikipedia.org/wiki/Modem#List_of_dialup_speeds

Re:It's 1996 again?

[rcpitt]

Actually the real "ceiling" was the 9600 baud one - the telecom engineers said there simply was no way to go above this. Then along came the Telebit Trailblazer - 18,000 bps using a Motorola 68000 and a signal processing chip.

AT&T started buying them just to test telecom lines as they split the spectrum into 512 discreet bands where the telecom's tools split it into 16 bands.

The concept of phase encoding had never before been practical - now it is the ONLY way we encode things. What's next???

Re:It's 1996 again?

[rcpitt]

If you need a tower, your cell is too large

Re:It's 1996 again?

[icebike]

Then the phone company trucks arrive, and sell you an ADSL modem which they hook up to the EXACT SAME WIRES, and all of a sudden you are zipping along at 24 Mbit/s.

So...

Re:It's 1996 again?

[rcpitt]

Telus, the local CLEC, is rolling out 15Mbps in the local loop to server TV (competition to the local cable company who is of course now providing telephone). I spoke to the local installers as they were adding $100,000 worth of hardware to the local SAC(sp?) box, just around the corner from my home.

Twisted pair can carry a tremendous bandwidth - for some distance. The distance is getting longer as the technology advances but there likely is some reasonable limit. The point is that as we approach that limit, the distance is going to approach that at which it makes sense to put in fiber to replace it.

In the mean time, as the spectrum we know (i.e. is financially viable to put in play) about (below 60GHz today) gets used, the move to replace it for fixed use will include fiber so will keep up with the bandwidth needs, freeing up the airwaves for use strictly for mobile - and making the cells ever smaller.

Re:It's 1996 again?

[Dare nMc]

I wouldn't grantee too much on AM/shortwave. To transmit efficiently you may want a good sized antenna but couldn't the small devices still transmit on higher frequencies, and receive on the lower frequencies with the base stations being huge still?

Re:It's 1996 again?

[rcpitt]

"standard" voice is current loop. The local loop can be miles long but the typical frequency is 300-3000 Hz

But... take a pair of wires and treat them as a radio antenna and you can do all manner of interesting things on it. Add in a signal processing and evaluation loop (intelligent frequency selection with adaptive signalling) and you can select a set of frequencies and signaling methods that can push an incredible amount of data down that twisted pair, even though it is also being used as a current loop for POTS (Plain Old Telephone Service)

Then add in phase modulation and other higher methods of encoding on one or more frequencies or bands.

That's the magic that the Telebit people pioneered. They really have not been given their due IMHO. $5000 (CDN) got us a modem that would walk all over the typical 1200Baud (and later 9600Baud) modems of the day.

Re:It's 1996 again?

[Anonymous Coward]

Eh, No. It's 64K bits/sec T0 (telecom t3 is 48 channels of T0, 1.3 Mhz).
Signaling occupies a portion of the spectrum and that's why it's limited to 56Kb
The interface is 8 bits serial at 64 KHz. 8 Bits, 8 KHz = 8000 Hz.

Re:It's 1996 again?

[rcpitt]

"You cannae change the laws of physics!" say Scotty - but then of course you can change the rules of the game and use a completely different concept on the same pair of wires.

Pair of wiress as current loop = frequency limitation to audio in loops measured in miles

Pair of wires as antenna = different rules in loops measured in wavelengths

Re:It's 1996 again?

[rcpitt]

Actually, most phone lines are both - current loop for the voice and DSL for the data - that's why there filters supplied with the modems - to stop the High Frequency stuff from being attenuated by the current loop devices (the phones). Put the filters in the circuit with each of the phones and they no longer interfere (so much)

Re:It's 1996 again?

[fluffy99]

56k modems are not analog; they are digital.

The v.90 protocol is a trick to send a digital signal over an analog medium, avoiding the normal Nyquist sampling limitations that set 28.8k analog limit. Very clever piece of work I think.

As an example, image you have a light bulb that can go to 4 different levels of brightness and someone standing far away could distinguish what the 4 different levels were. For a modem, that's all done during that initial handshaking noise. The person seeing the light is basically getting a 2-bit digital signal.

If DSL was confined to 4000 hertz like your 56k digital dialup modem, it would still be limited to the same 7 bits * 4000 hertz * 2 == 56000 bits/second.

POTS samples the analog signal at an 8kHz rate, but the analog signal is filtered below around 3200 Hz to avoid Nyquist problems. The v90 relies on that 8k sample rate * num_usable_bits => bandwidth. For a perfect connection, if all 8-bits could get through you'd get 64k. As the phone connection travels digitally though the phone system, at least one bit usually gets "robbed" for phone system signaling. Usually it's more than one bit at various places.

Also during the handshake, the modems may decide that some of the 256 possible values of the signal (the constellation) are not usable, which further drops the data rate.

Re:It's 1996 again?

[fluffy99]

Even if DSL operated in the 0-4000 Hz range, it would use the spectrum much more efficiently than would an analog signal sampled at n times a second.

Hit send to fast earlier. Sampling faster would not help, since the frequency range is still limited. A higher resolution sample, say 256 bit would let you pass more data but I think you'd run into issues "smearing" the signal too much to define descrete values.

Re:It's 1996 again?

[MechaStreisand]

I may be wrong, but I thought that Shannon's Theorem dictated the absolute limits for the capacity of a channel. How is it that they were able to exceed that? Can you explain in more detail?

Re:It's 1996 again?

[Idiomatick]

Well, wireless I believe is fairly unavoidable. It is the way of the future. People will start having laptops and cellphones and e-book readers and wearable data w/e crap. And they will expect it to work full speed sending tons of data no problem. This could be a solution to that.

I think perhaps a cell 'tower' in ISP boxes could work (doing the last mile wirelessly), In my area I believe I share a box with about 4city residential blocks. It is something the ISPs already own and maintain, it has access and enough power. Doesn't even seem that horribly difficult to roll out.

Re:It's 1996 again?

[shaped.dither]

You don't have to be POTS to be called a "phone line". ISDN is also a phone line system. Also, the phone frequency range is more like 400-3400Hz (ever noticed the lack of bass from the phone?), making bandwidth more like 3000 Hz with 8 bit per sample encoding. And in fact, that comes close to actual data rates achievable with a "56k" modem. I really hope we get a 56k expert in this thread at some point. You and I are obviously not experts. :(

Re:It's 1996 again?

[currently_awake]

we're not even close to capacity. we don't even use the radio spectrum at 1%. drop the radio cell radius by half, and you boost capacity by 400%. use directional trancievers and you can give every device in range the full radio spectrum. using currently available technology, we can easily give every cellphone gigabit ethernet. of course, that would cost money. it's much cheaper to complain and have paid for congress critters hand you a massive profit by legally limiting competition. or you could just use all that old analog tv spectrum, that's still in use when it shouldn't be.

Re:It's 1996 again?

[modmans2ndcoming]

Just what I want... cell service that gets blocked by a sheet of paper.

Re:It's 1996 again?

[modmans2ndcoming]

90 GHz? at that freq why bother? the freaking air pollution would block the signal over the distance of a large room.

Re:It's 1996 again?

[modmans2ndcoming]

same way they can get your voice on the same wire as your internet... they have multiple non-interfering signals traveling on the line. 56Kbps of digital data per channel, do the math.

Re:It's 1996 again?

[coolsnowmen]

You could use microeletric gyroscopes to detemine orientation, and (in real time) use phased array antennas to only broadcast at the the closest tower.

Re:It's 1996 again?

[FlyingGuy]

Good grief....

YES DSL is delivered over your existing single pair copper wire phone lines.

DSL Currently has a MAX length from the DSLM, pronounced "dee-slam" of about 18,000 ft, or a little under 4 miles from the Central Office where the DSLM is located.

When DSL was first introduced the DSLM equipment was ALL located in the telephone companies Central Office or CO although it has since been pushed out farther from the CO as more and more fiber has begun replacing the main trunk lines. Prior to this, you could physically trace your pair of copper wires that you hooked your phone to all the way back to the central office.

There are still MANY MANY CO's that are still this way. If you are friends with a telephone company guy ask him if he can take you into the CO some time and what you will find is a hybrid system. Much of the original copper has been replaced with fiber as far as the main feed trunks go, but there is still quite a bit of copper running from the central office, inside you will see a VERY large "A" frame structure and that is the cross connect point between the phone switches and the copper pair that does, in point of fact, run from there, to your house where it terminates on your NI ( aka the Network Interface, aka the little gray box on the side of your house ) which a fancy name for a box that has some screw terminals in it and a relay. The relay is used so that when you call the telephone trouble line ( 611 in most of California anyway) the telephone company can simply send a signal down your line and "Loop the NI" to test from the CO to your house ( for you data guys it is the same thing as looping the "Smart Jack" for a T1 circuit )

Now then, since deregulation and the lawsuit, the result of which require the Bell companies to lease their copper from the CO to your house, all of the other DSL companies DSLM's were put into to locked enclosures in the CO as they were the property of Covad, SpeakEasy, Slip Net, etc. etc.. Now AT&T at least in the San Francisco Bay Area is replacing most of their Main Trunks with Fiber and creating what are essentially very tiny little CO's all over the place. They do not run fiber to your house, what they do with these little CO's is shorten the copper run to a under around 1000 feet or less in most cases less then 500 feet which is a completely new ball game, since in the case of hi speed signaling over copper, the shorter the run the better, since you have to change something when the run starts getting longer.

In the case of DSL the longer the run the slower your data right is OR you change from SDSL to ADSL (Symmetrical DSL and Asymmetrical DSL respectively).

So yes, you can have your plain old dial up fun on the same line as your Internet signal because they use very different frequency bands. POTS ( Plain Old Telephone Service ) occupies the lower frequencies and DSL occupies the upper frequencies that two pieces of copper wire can transmit.

Re:It's 1996 again?

[crispytwo]

All this talking about problems can be a non-issue.

If telecoms are relegated to 3rd tier carriers (as they should be), then these devices can use local wifi instead as a priority routing and the 4G/3G/edge, etc carriers as the next... etc.

The Australian idea of ad-hoc networks previously mentioned here could extend the wifi reach into areas a little further too.

On top of that, all the voice network bandwidth should be tossed onto the data pile and open up that spectrum for wireless data.

It might be a bit ugly choreography but the phones pretty much do that now... except they have this voice junk... and no built in ad-hoc relay.

But really, how hard can that be? It's only typing!

Re:It's 1996 again?

[Anonymous Coward]

I'm not arguing infinite information can be carried in a given bandwidth bandwidth, Shannon pretty much settled that 50 years ago. I'm just saying your example is non-helpful, as the transmission medium of a phone line is not the limiting factor, it's the digital encoding system used by the phone company at the trunk that limits bandwidth. All of that clouds an already difficult topic.

And for the matter at hand, 2G and 3G are quite spectrally inefficient. LTE will be much better. See http://en.wikipedia.org/wiki/Bandwidth_efficiency#Comparison_table
Also, bandwidth/square meter is limited, but that can be solved in the cell system by placing more towers and having better power control.

In summary, the initial question from the article "So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is? What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks?" can be answered, switch to a (approx 4x) more spectrally efficient system in the form of LTE, and place more towers. The sky is not falling, and the carriers can handle the increased demand without any drastic measures.

Re:It's 1996 again?

[rohan972]

>>>Same line, different signal.
>>No... same line, different bandwidth.

I'm sure you're correct but for someone with my level of knowledge on the subject there is no practical difference. I've never bothered to learn more about that than I needed to get my connection working. I assumed that since the audio signal from using the phone and the ADSL connection would work at the same time that it was different in some way but didn't know the details (although I knew it was the same line because I wired the connection) ;-)

Does that mean that a DSL modem still uses an audio signal? I've had a quick look at wikipedia and a couple of pages google turned up but it's not clear to me from what I read.

Re:It's 1996 again?

[Mr.Radar]

I can see OTA TV going away (ATSC is horrible for mobile reception and cable/satellite work for almost all other purposes) but I predict an uprising if analog FM radio is ever taken away. Right now if you go to any dollar store you will probably find at least 1 FM radio. My car, alarm clock, emergency flashlight, MP3 players, (dumb last-gen) cellphone, and home theater receiver all have FM radios built in. It is possibly the most ubiquitous mass communications medium if you go by the number of receivers per capita.

The technology is extremely mature, very inexpensive, not (currently) patented, about as portable as it gets and it doesn't require a $50 monthly subscription to use. Sure *you* might not listen to FM radio but I and millions of other people do every day. Every car built since the 70s has an FM radio and people still listen to it every day when they drive. I get my news, in real time, from public radio between classes on my MP3 player's built-in FM tuner. Other technologies might be able to partially replace FM, but they will be massively more expensive and they will probably never achieve the reach FM has today.

Bottom line: because of the built-up infrastructure, FM is here to stay.

Re:It's 1996 again?

[vadim_t]

ADSL bypasses the problem entirely.

Phone lines have a total bandwidth of 64k, of which something speaking through an analog line can only get 56k, with the rest being used for signalling data. There's no way to go any higher. Think of trying to play 24 bit, 96KHz music into a system that only records 8 bit at 11KHz. No matter what you put into that line, you're not getting more quality out of it.

So how does ADSL do it? By bypassing the phone infrastructure entirely. The limit isn't in the line itself, it's in the endpoint. ADSL sends a signal through the line that gets received by special hardware sitting before the telco phone equipment which handles a much higher frequency range.

Re:It's 1996 again?

[MechaStreisand]

Except that if 35k is the Shannon limit, then you can't exceed that. Simply sending a signal at 7 bits per sample, sampled 8000 times per second, doesn't mean that it's going to get to its destination. In fact, if the Shannon limit is 35k, then that signal is guaranteed to get corrupted, and you'd need to put error correcting codes in it, thus bringing down the data rate of useful information to something less than that limit. And if you are able to send such a signal down the wire and it isn't corrupted, due to lower than usual noise in the channel or whatever, then the Shannon limit for that medium must be at least 56k, or else you wouldn't have been able to successfully transmit it.

See what I mean?

Re:It's 1996 again?

[TikiTDO]

Now first off, I'm not sure why you're trying to bring Nyquist's Theorem into this discussion. We've already established that we do not particularly care about reconstruction the analog signal, and certainly not about its accuracy. Please stop trying to change the argument.

Shannon's Limit is a much better an example. We have C = B * Log2(1+S/N). B is fixed, so we are left with the SNR as the determining factor. Now granted, there may be physical limits on how high this value could ever go, but I have not seen any proof of such, so I will not assume they exist until mathematically proven otherwise. With that in mind, any current limitation on this value is still technological (medium quality, techniques to minimize noise, etc), not physical. If you can prove the SNR fundamentally cannot go above a certain value, I would love to see it, and will gladly admit that you are correct. If not, then I thank you for proving my point: As SNR goes to infinity, so does the channel capacity follow. Q.E.D.

So you see, I do not need to change any laws, when they do not actually prevent me from doing something.

Re:It's 1996 again?

[catmistake]

There is only so much spectrum available.

Sure... per cell. How many wireless users can we cram into one cell? If a cell area in Manhatten gets saturated, how would this affect a cell in Long Island? I don't see this as an approaching unsolvable problem. There are going to be peak usage times, and for many the network will be down in a saturated cell, just like it happens already all the time in various overpopulated areas. This is absolutely a "sky is falling" non-issue. Nothing to see here.

Re:It's 1996 again?

[osu-neko]

For the pure analog phone signals, the Shannon limit is indeed 35k, and that was approximately the limit for V.34 modems. 56k PCM modems break the limit by assuming one end or the other (usually the ISP's end) is digitally terminated. If at least one end is digitally terminated, they can sync their signal with the digital phone network in a way that reduces quantization noise, and if you can reduce the noise, you increase the limit per Shannon's Theorem.

Re:It's 1996 again?

[Anonymous Coward]

Until someone comes up with a better way to multiplex the signal.

Re:It's 1996 again?

[Profane MuthaFucka]

Oh, you must be confused. On Slashdot, it's ILLEGAL to be correct, and it's RUDE to give actual facts that you didn't invent yourself. So of course you get modded TROLL.

Also, it's considered IGNORANT to disregard the moderation tags and make your own judgements about the value of a post. Those moderation tags are purposely put there to form our opinions.

So if doesn't matter if I might personally think you are informative, or that I've learned something from you. The tag on your post says TROLL, so you can just suck my cock, you dirty troll.

I'm sorry, but that's how moderation society works on Slashdot. It cannot be changed, according to Pudge and Malda, everything is functioning according to their ideal.

Re:It's 1996 again?

[steve_bryan]

It is inspiring to see someone try so hard to inject some actual physics into a discussion but the magical view of the world seems to have too strong a grip. Something that might be missing from these accounts is the brutal economics. The 9600 baud modem I used to do contract work in Silicon Valley from Minneapolis in the early 90's cost about $800. The voice circuits it used were far from pristine so some days it just didn't manage a data transfer at all. I don't think many thought there was a physical limit but rather economic reasons greater speeds weren't available yet. Later I got ISDN and it delivered its 64K per channel but it cost plenty (over $200 per month).

Re:It's 1996 again?

[icebike]

ADSL bypasses the problem entirely. So how does ADSL do it? By bypassing the phone infrastructure entirely.

No. Sorry that is simply NOT true.

ADSL uses the exact same two wire copper pair that your analog signal used to use. Its the same infrastructure you had previously. In most cases the switch to adsl uses the EXACT same physical stretch of wire.

The only difference is that instead of sending sound (analog) down the wire they send electrical pulses, 1s and 0s: digital data.

Nothing changed other than someone started thinking OUT of the box. Someone told the analog engineers to take a hike.

And yet this nonsense about maximums persists.

I just told you in the GP post that adsl can do 24Mbits/s on a single pair of plain old telephone wire.

You turn right around, stick your fingers in your ears, sing LA LA LA loudly so that you can't hear men and and insist that there is ONLY 64k of total bandwidth on those same wires.

(And some fool mods you informative).

Recent months have seen stories on Slashdot about even higher speeds achieved on plain old copper wires. Gigahertz speeds.

This is why this whole thread about inadequate bandwidth is totally nonsense. New technology and totally different ways of using what we already have will continue to produce ever more information density in the same radio spectrum.

Instead of discrete channels formerly used, we are already seeing spread spectrum transmission pumping huge volumes thru common bandwidth in unlicensed spectrum.

Some of those technologies are in the lab today. Some haven't even taken shape in any one's mind yet. And still more await the prerequisite inventions that always give birth to new technology.

But one thing is certain. There is a LONG way to go before we even come close to "saturating the airwaves."

Re:It's 1996 again?

[PeterBrett]

And for the matter at hand, 2G and 3G are quite spectrally inefficient. LTE will be much better. See http://en.wikipedia.org/wiki/Bandwidth_efficiency#Comparison_table

You're comparing the maximum achievable spectral efficiency. What will the average efficiency achieved in practice be?

Re:It's 1996 again?

[SlashWombat]

Actually, thats only true to a small extent ...Spread Spectrum allows many transmissions on the same frequency with only a small degradation when multiple sites are active (but using different "golden keys"). The penalty is slightly more noise, but hardly an issue. So there are ways to use the spectrum (much) more efficiently!

Re:It's 1996 again?

[Serious Callers Only]

DSL disconnects the POTS line, and replaces it with a central box (DSLAM) that converts the incoming twisted-pair and passes it along to higher-quality fiber or coax.

You're being misleading here in an attempt not to be proved wrong. DSL is indeed over telephone lines (as normal people understand them).

If you redefine 'line' to mean all the terminating equipment too as you do here (hey, why not include the old analog modem as well while you're at it?), then I guess in some sense DSL does not use phone lines (a.k.a. twisted pair), but back here in the real world, when people say line, they mean the wire, not the terminating equipment, because that's all that matters to them - they can unplug a telephone modem, and plug in a DSL modem to the *exact same telephone line all the way to the exchange* (so long as the other end deals with it) and get faster service. The telephone line from customer to exchange is exactly the same, and then at the exchange they need better equipment to multiplex etc. and hand off signals to a more capable backbone, but all of that is not to do with any hard limit on the copper wires themselves.

Would you accept that the limit with old analog modems was in fact not a hard limit of the cable itself, but in fact a limit of the older equipment connected to either end? If that's the case, the analogy kind of breaks down if you're using it to say that wireless can never get faster, because all you are really saying is that that there are hard limits to the broadcast/receive equipment given a certain method of transmitting.

Re:It's 1996 again?

[PeterBrett]

Shannon's Limit is a much better an example. We have C = B * Log2(1+S/N). B is fixed, so we are left with the SNR as the determining factor. Now granted, there may be physical limits on how high this value could ever go, but I have not seen any proof of such, so I will not assume they exist until mathematically proven otherwise. With that in mind, any current limitation on this value is still technological (medium quality, techniques to minimize noise, etc), not physical. If you can prove the SNR fundamentally cannot go above a certain value, I would love to see it, and will gladly admit that you are correct.

For an infinite SNR, you require one of the following conditions to be true:

1. The noise power is zero. This cannot be true; even if your receiver and transmitter are perfectly noise-free, your phone cable will not be at 0 K, and you will therefore have some thermal noise (v2 = 4kTB, where R is the resistance of the cable, T is its temperature, and k is the Boltzmann constant.
2. The signal power is infinite. This also cannot be true, since your phone cable will melt if you try to drive it with an excessively large current, and the insulation will fail if you try to drive it with an excessively high voltage.

There is therefore some finite upper limit on the SNR which cannot be exceeded for the physical medium of your phone line, before we start wondering about the cost of manufacturing and powering the equipment at each end, and any relevant legislation (since your phone line will act as an antenna at some frequencies).

Re:It's 1996 again?

[Anonymous Coward]

The use of lower frequencies also requires (much much) longer antenna's 1/4 wave at FM frequencies is around 3 feet ... anything shorter generally doesn't radiate (or receive) very efficiently. A lot of comments on this thread are being posted by people blowing out of their arses, Many comments prove the posters don't know the difference between shit and clay!

Re:It's 1996 again?

[Gandalf_the_Beardy]

You bother because there is a lot of unused bandwidth there that you can shove a signal up - and the record distance is something like 50km. Certainly for small cell sizes in cities it's eminiently feasible to run this sort of frequency, it just sadly needs a lot more infrastructure investment.

Re:It's 1996 again?

[vadim_t]

Er, no.

There are two different things here: The limit of the line and the limit of the receiver at the end of it.

The limit of the receiver in an analog line is 56k. You can't dial a phone number on an analog line and then establish a connection at ADSL speeds from one end to the other. It's like this: ("=" is a fat pipe, "-" is a slow one)

[your modem] ==phone line==(--telco DS0--)==[other modem]

The phone line might be able to handle 10mbps fine, but the DS0 you get inside the telco has a hard 64kbps limit (of which you get to use 56k) and no encoding technology will change that.

The reason ADSL works is because it's not going through that bottleneck:

[your modem] ==phone line==DSLAM==(--telco DS0--)==[other modem]

The telco samples 8 bits at 8000 Hz, so there are frequencies that won't get through it, ever. ADSL works by sending frequencies the telco won't transmit through the phone line, but the DSLAM can use them. Notice how modems haven't budged an inch since they reached 56k. There's simply nothing left to squeeze out.

Your phone line also has a very definite physical limit, which is why ADSL performance depends on the kind of line and its length, and the DSLAM is probably located at some junction near your house. This is the reason why people are starting to get fiber at their house. It's also precisely what the FCC is talking about here -- the medium itself has a limit and no encoding is going to change that. Better encodings simply get closer to the ultimate physical limit, and modern encodings are pretty much perfect already.

Re:It's 1996 again?

[TheRaven64]

Increases in CPU power also allow for more data in a given bit of spectrum. You can have two users talking to a base station on the same frequency without problems, because they have different return paths (bouncing off different bits of terrain, buildings, and so on) and so you can differentiate their signals based on these characteristics. Doing so, however, requires a lot of processing power.

A hundred years ago, Tesla was sending radio messages using a spark gap, which basically produced a small EMP. This blanketed the entire spectrum; you could only have one transmitter in a given area. Then came AM, which let you use a small frequency range. FM allowed an even smaller range for the same amount of signal. Today we're using much more advanced modulation techniques to squeeze a lot more in (with overlapping channels) and there are a lot of research projects squeezing even more into smaller and smaller ranges.

The amount of data you can squeeze into a bit of spectrum depends on how accurate you can build your DACs and ADCs (so you can differentiate smaller changes) and how much processing power you are willing to dedicate to decoding the output from the ADC. You can also throw in technologies like phased array antennas, that have only recently started to see non-military use, which let you use a low-bandwidth carrier signal to track the location of a device and then use a more focussed transmission than an omnidirectional broadcast to communicate with it.

Re:It's 1996 again?

[commodore64_love]

>>>sell you an ADSL modem which they hook up to the EXACT SAME WIRES

Not true. What used to be a tens of miles long low-quality telephone cable is now truncated just a few hundred feet from your home, and then upgraded to fiber or coax. NOT the same wires or system or bandwidth limitations (4000 hertz).

Re:It's 1996 again?

[klapaucjusz]

This is a physical problem. There is only so much spectrum available. Once the air is saturated on the allocated frequencies, we are done. No more room, period.

Nonsense. There's plenty of ways to make wireless networks scale.

Just off the top of my head, there are physical layer techniques, such as MIMO, that change the value of Shannon's limit by dramatically improving the signal/noise ration. There are network layer techniques, such as mesh networking, that allow you to use a larger number of less powerful radios, and hence allow more sharing of bandwidth in a given space. There are application layer techniques, such as distributed caching.

And all of that is without getting the politicians involved to give us back some of the bandwidth they have been giving away to corporations.

Re:It's 1996 again?

[commodore64_love]

>>>ADSL uses the exact same two wire copper pair that your analog signal used to use. Its the same infrastructure you had previously. In most cases the switch to adsl uses the EXACT same physical stretch of wire.
>>>

Not only are you wrong, but you managed to be wrong three times. The old telephone wire and the new DSL is NOT the same copper pair, not the same infrastructure, and not the same physical stretch of wire. Here are the differences:

- The old telephone infrastructure was bandlimited to 4000 hertz. DSL is not.
- The old telephone copper traveled miles-and-miles, and was very poor quality due to that long distance.
- DSL is terminated just a few hundred feet from your house (before the signal degrades), and then upgraded to high-quality fiber or coax which carries the signal over long distances. DSL is 99.9% fiber/coax with just a little bit of copper at the end.
- QED not the same system or infrastructure or copper (since DSL is mostly carried by fiber).

Re:It's 1996 again?

[Anonymous Coward]

This is a physical problem. There is only so much spectrum available. Once the air is saturated on the allocated frequencies, we are done. No more room, period.

This is technically false. Once the air waves are saturated in an area, an additional cellular tower may be constructed. The adjacent towers will then operate at lower power and instruct the cellular phones to only transmit with sufficient power to reach the nearest tower, which may then be hard wired (via copper or fiber, depending upon capacity needs) to the central office. Doing so will increase teh battery life of the phone and maintain consistently high signal strength. This is the concept of a cell. Admittedly, there is a limit to how many tower may be packed into a given area with existing technology. Another solution, however, is to use CDMA. This effectively reduces the digital signal quality to gain a commensurate amount of capacity. Those answers are merely within the realm of existing technologies in use. We can further expand these capabilities with other techniques not currently implemented on the phones, such as spread spectrum transmissions below the noise threshold.

We are not nearing the actual capacity of the airwaves from physics or technology. We are nearing the capacity of the airwaves from an economic standpoint.

Re:It's 1996 again?

[klapaucjusz]

Phone lines have a total bandwidth of 64k

Huh?

A phone line is just a copper twisted pair. ADSL uses the very same copper.

64kbit/s is the rate of the ADC that the phone companies have been hooking to the telephone lines since the 90s, but that has nothing to do with the phone line itse.f

Re:It's 1996 again?

[ResidentSourcerer]

I thought that the whole principle of cell broadcasting was that as the demand grew, the cells shrank. So if the demand grows by a factor of 10, we put in a huge raft of low power cell stations.

It MAY mean that in cities with large buildings we will need to come up with more frequencies to have enough so that cells that are adjaacent vertically can be different from all of their horizontal neighbors.

In theory a flat cell plane can be done with 3 frequencies so that no two adjacent cells use the same frequency. (In this discussion a given frequency is broken into multiple channels.)

If cells can be packed vertically too, then at first look it would take 9 to do the same. However, I suspect that in conditions like this, you want to have more than one different cell between reuse of the same freq. For the flat plane I think this can be done with 7. The 3D version is beyond me right now, but takes at least 21.

Add to that: There may be merit in have a mix of large cells and small cells. Large cells are used by people on the move, small cells for people who have settled into a building. Large cells would be flat so could be handled with another 3 freqs.

Re:It's 1996 again?

[Anonymous Coward]

>ADSL uses the exact same two wire copper pair that your analog signal used to use. Its the same infrastructure you had previously. In most cases the switch to adsl uses the EXACT same physical stretch of wire.

Umm exactly what he said. Its a different technology at the endpoint in the case of DSL the DSLAM.

Re:It's 1996 again?

[commodore64_love]

P.S.

>>>the only difference is that instead of sending sound (analog) down the wire they send electrical pulses, 1s and 0s: digital data.

56k digital modems also use 1s and 0s (duh). Pure analog modems max-out at about 34k. And the maximum exists because when you limit yourself to a 4000 hertz wide spectrum, you are confined by the physical limits or the universe. On telephone wires, that limit is 7 bits * 4000 Hz * 2 == 56000. On broadcast Digital AM radio, it's about 20,000 bits/second.

Basic math. Basic physics. Freshman level. If you have an engineering degree you should hand it back.
.

>>>adsl can do 24Mbits/s on a single pair of plain old telephone wire.

Incorrect. ADSL disconnects the old telephone wire (4000 hertz limit) and reconnects it to high-quality fiber or coax (unlimited). It is NO longer part of the old 1800s-era telephone system. It's an entirely new technology.

>>>This is why this whole thread about inadequate bandwidth is totally nonsense. New technology and totally different ways of using what we already have will continue to produce ever more information density in the same radio spectrum.
>>>

Except you cannot change the laws of physics. A 20 megahertz channel (i.e. the entire with of FM radio) can only carry 330 Mbit/s per Nyquist's Theorem. That is the physical limit imposed by the universe and you will never exceed it.

Re:It's 1996 again?

[ResidentSourcerer]

Maybe ADSL can do better than 64 kbit, but MY phone company won't even provide that.

Numbers quoted are that I have to live within 18,000 feet wire distance from the exchange. (I live 40,000 feet crow flight)

So I'm stuck with satellite. It's nominally 500Kbits down, 128kbits up. Actual is about 80% of that. I just used jigdo to download the debian DVD. That took several days. (I figure on about a GB/day when things are good.)

Re:It's 1996 again?

[commodore64_love]

Your phone line also has a very definite physical limit..... It's also precisely what the FCC is talking about here -- the medium itself has a limit and no encoding is going to change that. Better encodings simply get closer to the ultimate physical limit, and modern encodings are pretty much perfect already.

QFT. (quoted for truth). At last somebody understands. If you have a fixed width of spectrum (4000 hertz) you can only squeeze so much data through it (56k).

The fact that there are engineers on here claiming you can squeeze as much data as you want through a 4000-hertz limit is extremely depressing.

Re:It's 1996 again?

[commodore64_love]

>>>The concept of phase encoding had never before been practical - now it is the ONLY way we encode things. What's next???

Trellis modulation. With phase encoding the speed limit of a modem was limited to 14k, but with trellis modulation they were able to get 34k. Then they went to digital encoding which maxes-out the telephone line to 56k. The end. That's the physical limit of the universe - you cannot get any more data through a 4000-hertz-limited telephone line.

Re:It's 1996 again?

[commodore64_love]

Now first off, I'm not sure why you're trying to bring Nyquist's Theorem into this discussion. (snip). Shannon's Limit is a much better an example. (snip). So you see, I do not need to change any universal laws, when they do not actually prevent me from doing something.

Okay.

Y'all think the 56k speed limit on telephone modems is non-existent. Fine. Prove me wrong. Build a modem that goes faster. I would love to buy a dialup modem that gets 128k or 200k, especially for my laptop when I'm stuck in hotels with nothing but a phone-based internet.

Ye seem so damn sure the 56k limit for a 4000-hertz-wide telephone doesn't exist (or the 20k limit for Digital AM radio). You build it. I'll buy it.

Re:It's 1996 again?

[commodore64_love]

>>>You don't have to be POTS to be called a "phone line"

Yes. You do. In this discussion we're talking about POTS invented back in the 1800s, not modern systems like SDN or DSL, and POTS is defined as having a 4000 hertz bandwidth. If you're going to build a POTS-compatible modem, you are confined by that limit, just as the FCC in this article is constrained by the size of the radio spectrum. Get it?

Re:It's 1996 again?

[commodore64_love]

>>>DSL is indeed over telephone lines (as normal people understand them).

False. DSL is over a standard twisted-pair line, that is a few hundred feet long, and then converted to higher-quality fiber or coax. It has a bandwidth well over 200,000 hertz, mainly due to the fact it's 99% fiber or coax.

POTS is also twisted-pair, but due to its extreme length (miles and miles), is bandwidth-limited to 4000 hertz wide - about the same as a European AM station. POTS' bandwidth constraint limits it to 56k (digital) or 34k (analog). AM's bandwidth constraint limits it to about 20k (digital radio). If it were possible to send more data over telephone or Digital-AM, then the engineers would have done it. They can't because the universe places restrictions, just as surely as you can not exceed 186,000 miles per second. Good God people! Have you never taken Physics 101??? :-|

Re:It's 1996 again?

[david_thornley]

DSL is over telephone lines. When I got DSL, they didn't change the lines.

Copper wires can support more than a 4 KHz (or whatever) band, but the equipment at the central station didn't. The phone company just runs my call into a DSLAM now rather than whatever they use for POTS. They then have to send that signal along to my ISP in a higher-bandwidth form than my ordinary phone calls, but that's on their end and I really don't care about the details. (They also need a cleaner connection than for POTS.)

However, the relevance is that standard equipment is limited in bandwidth, and that bandwidth limitation capped modem speeds at 56K. Modem speeds haven't changed in quite a few years, despite all sorts of advances in theory and technology. The only way home connection speeds could be improved was to provide more frequency bandwidth.

This implies that the issue is with increasing amounts of data transfer and the same limited bandwidth. Eventually, the data transfer rate will overflow what the bandwidth allows. This is a hard physical limit.

There are things that can be done. Phone companies can make smaller cells, with towers closer together, so there isn't as much traffic in one place. The FCC can allocate more frequencies. Neither of these is going to be cheap, and they won't increase bandwidth by all that much.

We do have a problem here.

Re:It's 1996 again?

[commodore64_love]

The key that most of ye are missing, is that while it's possible to upgrade POTS to DSL, and thereby increase from 4000 hertz to >200,000 hertz bandwidth, you can not do that with the radio spectrum. The radio bandwidth is fixed. Engineers working with wireless are doing the equivalent of trying to squeeze more data through a bandwidth-limited 4000 hertz phone line, and there's not way to upgrade it.

Re:It's 1996 again?

[chicago_scott]

Try reading what the comments says, not what you want it to say. A DS0 circuit is digital. My reply was concerning analog circuits. That's why I said "for the sake of clarity", because analog twisted-pair itself has a limit of 2400 bps, and it's the "magic", as you so elegantly put it, that achieves a 56 kpbs transfer rate. Unlike your comment mine wasn't meant to be condescending or insulting, it was simply stating a fact regarding analog twisted-pair.

And in case you missed it, which you probably did, the underlying point is that new techniques (such as the "magic" you described) are usually devised in order to push technology beyond what the current limits are thought to be.

Re:It's 1996 again?

[chicago_scott]

Whatever professor is teaching this curriculum should be shot.

Valium may help.

Re:It's 1996 again?

[LeDopore]

Once the air is saturated on the allocated frequencies, we turn down the power of each cell tower and make cell towers closer together. Repeat as needed, where needed. (Granted, for this to work, mobile devices also would have to limit their transmit power to just what is needed. Still, the tech challenges aren't insurmountable.)

Re:It's 1996 again?

[drinkypoo]

Lower frequency shortwave and AM radio will probably survive, simply because it's not practical to carry-around 100 foot long transmitting antennas with your phone.

Honestly, what else do we really need? I only want to watch TV over the 'net anyway. If you want people all watching at the same time, just kick out a multicast stream at broadcast time (I hear multicast works on IPv6) and charge people (or show them tons of commercials) for rewatch.

Re:It's 1996 again?

[drinkypoo]

The only difference is that instead of sending sound (analog) down the wire they send electrical pulses, 1s and 0s: digital data.

Wrong. They send both the analog sound AND the broadband (multifrequency) digital data as well. The filters in your house remove the high-frequency digital stuff from your handset lines, and prevent weird handsets from putting weird high-frequency stuff which the telco formerly ignored onto the line. The DSL modem only speaks the digital broadband stuff, and your phones are not supposed to produce any high-frequency tones, just DTMF and whatever can be produced by the human voice. Of course, RF noise &c can propagate into your phone network, hence the filters are bidirectional. The DSL modem filters or ignores the analog voice information. ISDN is all-digital; the data for DSL is all-digital, but unlike ISDN it can be carried on the same copper as POTS.

Re:It's 1996 again?

[Anonymous Coward]

You're correct that ADSL communication can be carried on the same wire - from your home or business to the switching station. Alot of what DSL did was removing high-frequency filters located at these switching stations. The filters improve voice communication by removing high frequency noise, but these higher frequencies can be used in digital data transmission to dramatically improve performance.

Maximums absolutely exist; Shannon's Law tells us there is an absolute maximum to how much data can flow in a channel. The potential for innovation, while not tapped out yet, is not limitless.

Re:It's 1996 again?

[FlyingGuy]

Yes you cannot invent more wireless spectrum so all you can do is try and figure out ways to minimize the bandwidth required for each discrete signal, or channel if you will that each device needs.

The problem is that as we push ever higher in frequency the amount you end up having things like trees and the like forming RF shadows. We have all experienced this problem as we go into elevators and our cell signal vanishes since as you push into the Gigahertz band we now are trying to make radar frequencies go through and object instead of reflect off of the object.

Those RF engineers are smart guys and will figure something out though. Who knows, this might lead us back to Packet Radio for phones!

Re:It's 1996 again?

[fluffy99]

What exactly do you mean by analog twisted pair, as that's not a normal term used by the telco industry? If you're talking about the unshielded twisted pair wire to the residence itself, then 2400bps is certainly not the limit. You can push a 45 mps DS3 up to 1/2 mile on copper, and a ISDN or T1 circuits for a few miles with no problems.

If you're talking about the usual equipment connected at the telco end of a FXS/B1 analog circuit, then 2400bps still is not the limit. It's the 56k as explained above for clean lines.

Also, although the spec says it possible, in practice you never see just a raw digital DS0 on a copper pair. It's usually part of a larger circuit such as a T1/DS1, sonet/atm, or larger circuit.

Compression has little to do with it. Off the shelf fax machines run speeds up to 14.4, typically 4800 or 9600. The compression is on top of the actual line rate.

Re:It's 1996 again?

[drinkypoo]

No you're not. When you upgraded to DSL, the company disconnected the telephone line (bandlimited to 4000 hertz) with a standard twisted-pair wire (no upper limit). Furthermore they disconnected your house from the old phone service, and connected it to a DSLAM which converts the short ~500 meter cable to higher-quality coaxial or fiber.

Pac bell used to sell DSL to 17,000 feet, when the DSLAM lived in the CO. In some markets (like where I live) pretty much all customers are served by the CO, with no hardware in the box on the corner, so the current ~14,000 foot limit leaves most of us out in the cold. Population density isn't high enough to justify installing more hardware here, unfortunately, so I am served (pretty poorly) by a local WISP. So really, DSL was originally implemented on the same old twisted pairs that we had our normal phone service on, and it still is. Ask me sometime about ISDN over non-twisted pair...

Re:It's 1996 again?

[TikiTDO]

Ok, here's a pretty basic example; the first thing that comes to mind really. Obviously this is not something that anyone would waste time or money to build, for reasons mentioned earlier, and it would still take a fair bit of work to get off the ground.

You have a modern phone cable, which is usable for DSL signals. You have a carrier signal at 1kHz, so you sample 1000 times a second.

The data will be transferred by every frequency from 3000-4000, at 1Hz intervals (This could be much smaller, but this is for the sake of example. Normal DSL has at least this many divisions). During each sample interval, the data frequencies will have an amplitude of either 1 volts (=1), or 0 volts (=0). Transform the sampled data into the frequency domain, and analyze the 3000-4000 range. You will see a set of peaks form the 3000-4000. Each peak represents a binary 1, while each pit is a binary 0. Let's say 25% of that is checksum/protocol data, so you have every millisecond, 750 bits being sent. With a 1kHz carrier, you are now at 750 kbits/sec, using the 3000-4000Hz range, more after you add in compression.

This is all possible using modern hardware, and could probably be built with minimal investment and engineering effort. Noise at the 3000-4000Hz range could be practically non existent due to the quality of the cable and shielding, and noise at higher frequencies could be safely ignored, as it would not actually interfere with the data being transferred. Obviously, you would never see this on the market; who would pay for a 750kbit service that interferes with phone conversations, when you can pay for a 7.5mbit service for service that does not.

The main point to realize is that our hardware is already capable of picking up signal in the GHz range. For instance the difference between 1 GHz and 1.001 GHz. What this really means is we can tell the difference between something that pulses a billion times per second, and something that pulses 1 billion, and one million times per second. In other words the difference between a 1 nanosecond period, and a 999 ps period.

If you think there's a market, feel free to take this as a starting point, and roll with it.

Re:It's 1996 again?

[TikiTDO]

Sorry for the confusion, I did not mean to imply that infinite SNR was possible, but I was simply trying to illustrate a limit, showing that as we trend towards a higher SNR, we can grow the capacity. Obviously with 0 noise, we could have infinite capacity, but that situation is quite unrealistic, at least for now.

For your point 1, I don't recognize the formula offhand (Still need my morning coffee), but the formula is missing the R which you define right after, but has a B, which I'm guessing would be the 4k. I'll assume that's just a typo, but please let me know if I'm mistaken. If the formula is v2=4kTR, then the easiest thing to target would be the R, and not the T. We are already making progress in the area of high temperature super conductors. As those become a reality, we will get all that much closer to infinite SNR.

Remember, this is all part a discussion of whether it is possible to fit more than 56kbit/s of data into the 0-4000 Hz range. The idea of infinite SNR is getting pretty heavily into the realm of science fiction. I only used the formulas since they were brought up, in order to illustrate that they would not invalidate my point.

Re:It's 1996 again?

[PeterBrett]

Remember, this is all part a discussion of whether it is possible to fit more than 56kbit/s of data into the 0-4000 Hz range.

Was it? I thought it was about fitting more than 56 kbit/s of data into the 4kHz low-pass band on a phone line.

And I disagree about reducing resistance being the big problem -- if you do the maths, you'll find that shot noise in the semiconductor devices at each end of the line is a much bigger deal. Also, copper wires are so 20th century -- for long distance lines (i.e. more than a hundred metres or so) fibre is better both in terms of cost and performance.

Re:It's 1996 again?

[icebike]

And more depressing are those that tell you you can't exceed 56k on copper pairs EVEN when presented with evidence that those same copper pairs can handle 24Meg, or with VDSL up to 53Meg.

This problem is settled physics. Your stubborn clinging to analog when the entire world has moved on is pathetic.

Re:It's 1996 again?

[icebike]

Sorry, there is no fiber involved in many ADSL conversions.
All you need is to be within 18000 feet of the nearest CO.

Some towns don't even have fiber. Its copper everywhere.

Time to move out of your analog world, and realize the rest of the world has gone digital.

Re:It's 1996 again?

[TikiTDO]

Well, that's what I thought was arguing. Perhaps that wasn't what was understood. Hard to say. For me the discussion has been the purely theoretical possibility of using modern technology to send a large amount of data over frequencies that were previously used to send much less.

Tying it to the original topic, this was a roundabout way of saying you could do the same for wireless, and avoid the problem of overcrowded bands. Granted SNR would be a lot more of a problem for wireless, but you are also working at much higher frequencies, and you have other variables you can play with to improve signal quality, such as spatial multiplexing for 802.11n.

Re:It's 1996 again?

[vadim_t]

Again, no.

Copper can exceed 56k obviously. Phone lines, as in, a copper pair WITH the telco equipment at the end that imposes a limit, can't exceed 56k. The reason people bring it up is to demonstrate how hard limits exist.

If it was simply a matter of encoding, there would be modems faster than 56k. But there aren't. No, DSL doesn't count, because it doesn't manage to push more through that bottleneck, it simply routes around it entirely.

If you skip the telco stuff and just use the copper you can go faster. But there's still a limit to how much faster.

Re:It's 1996 again?

[MechaStreisand]

Thank you. That's the answer I was looking for! I've not heard of that technique, so you've given me something to look into.

Re:It's 1996 again?

[Anonymous Coward]

Already done:
http://en.wikipedia.org/wiki/Smart_antenna
http://en.wikipedia.org/wiki/MIMO

No need for gyroscopes though. Digital signal processing of the received signal can accomplish this very well.

This is a large component of 802.11n

Re:It's 1996 again?

[modmans2ndcoming]

dude.... at 60 GHz we are already talking about the need for line of sight and a human body blocking the signal. Say goodbye to using my internet services in my car... the roof would block the signal.

Re:It's 1996 again?

[ShakaUVM]

>>Good God people! Have you never taken Physics 101??? :-|

Sure, but don't try to argue that the wiring in my old apartment building isn't the same old copper wiring that has been in use for 100 years. The only difference is the segment length, not the wiring in my building. These are two very different things.

Re:It's 1996 again?

[Serious Callers Only]

If it were possible to send more data over telephone

It was, and is, possible to send more data over physical copper telephone lines to a nearby exchange, by changing the technology used to broadcast and receive. That's what DSL does, at least here in the UK. The telephone line has remained exactly the same all the way to the exchange:

http://www.thinkbroadband.com/news/3660-what-broadband-speeds-could-the-uk-copper-loop-manage.html

As I'm sure you're aware, the DSL uses the frequencies unused by the audio telephone signal, which as you note is capped at 4000Hz. Perhaps the setup is different where you live, and DSL required rewiring in street-side cabinets too?

If you redefine telephone line to mean 'copper twisted pair line limited to 4000Hz and extending for at least several miles', then you are correct. I don't accept that definition of telephone line - neither does most of the rest of the world, because that is not the sort of line their telephone plugs in to.

They can't because the universe places restrictions, just as surely as you can not exceed 186,000 miles per second. Good God people! Have you never taken Physics 101???

Forcing yourself to actually address the issues raised by people you're arguing with (see question in my last post, or the definition of telephone line, which I acknowledged you see differently), might mean arguments feel less frustrating for you. It might also have the fortunate side-effect of reminding you that you are not always more intelligent than your interlocutors, and misunderstandings are not always due to their ignorance.

Re:It's 1996 again?

[Anonymous Coward]

Every car built since the 70s has an FM radio

My grandmother's old 1980 chevy impala had an AM-only radio.

Spectrum auction

[Scutter]

Isn't that why our government just auctioned off billions of dollars of our publicly-owned spectrum? So that companies could sell it back to us in the form of a three-year contract?

Re:Spectrum auction

[mblumber]

Minus the sarcasm, you're absolutely right.

The AWS and 700MHz auctions have opened up a vast amount of real estate to be used for high speed data. When that's exhaused, the FCC will start dolling out other valuble spectrums vacated by analog TV. I feel like today's RF environment is still fairly green, dispite Genachowski's comments to the contrary.

Re:Spectrum auction

[adolf]

As someone who is somewhat involved with actually using some (12MHz) of that recently-auctioned 700MHz spectrum, please allow me to say the following:

It's not vast. And it's not pretty. In fact, it's generally useless for common Internet access on any sort of grand scale:

700MHz is cool because people can use it at long distances from the central tower without much concern about their own antenna orientation. But once folks actually start to populate the network and, you know, use it, it gets hairy.

The correct answer, of course, is to ratchet down power and use more (and perhaps smaller) towers. But by the time you increase density enough that it becomes useful for any sort of popular usage, you've got so many towers/picocells/whatever that a mesh of bog-standard 802.11G starts looking far more practical.

*sigh*

Re:Spectrum auction

[stephanruby]

What happens? May be, he should just visit Seoul or Tokyo, and ask them what happened over there. That's the advantage of not being the leader of the pack anymore, we can go to the countries/cities that are leading, and time travel to the future that way.

The FCC is at fault

[dada21]

Having an organization that is bureaucratic instead of market driven is going to cause the biggest issues. Today, we still are wasting a significant portion of bandwidth on broadcasting when the future is point to point communications along with some form of P2P crowdcasting. Get rid of the public airwaves and work on letting the market come up with standards -- frequency hopping software radios, hive networks, whatever. It'll be more efficient, cheaper, and it'll provide for much more competition.

Broadcasting is dying.

Re:The FCC is at fault

[jameskojiro]

Hive Networks sound interesting, is that like a Borg's subspace interlink node?

Re:The FCC is at fault

[Anonymous Coward]

Awesome. I'm going to raise capital to build big towers that 'broadcast' transmissions on your favorite carrier's bands, unless they pay me $5,000,000 a year. 'Cause, like, without the FCC, it'll be all market driven, right?

Re:The FCC is at fault

[vux984]

Get rid of the public airwaves and work on letting the market come up with standards -- frequency hopping software radios, hive networks, whatever. It'll be more efficient, cheaper, and it'll provide for much more competition.

er... this is where cellphones are already heading. hell... they are already there.

Today, we still are wasting a significant portion of bandwidth on broadcasting when the future is point to point communications along with some form of P2P crowdcasting.

crowdcasting/p2p is going to evolve significantly. We are already near the cusp i think, given how much traffic is already p2p. Sooner or later p2p is going to be metered and restricted and paid for. As soon as that happens crowdcasting is dead in the water. It only works as long as everyone has 'unlimited bandwidth' right now the market is working out that 'we have a lot, but its not unlimited, but we won't meter it yet because we have enough that most people don't need to know its not unlimited and unlimited is easier to sell... so we'll just deal with the blowback when the very small number people run us into the limits.

Let something like 'crowdcasting video' catch on to the point that it can replace 'broadcast tv', where everyone anywhere watching a TV show is simultaneously p2p serving it back on to the network... at the point the jig is up; and the bandwidth meters will go up.

Re:The FCC is at fault

[angelbunny]

A daisy chain type mesh setup? Oh hell no! There is no way I'm going back to setups like that. Anyone remember apple talk?

Re:The FCC is at fault

[commodore64_love]

>>>Today, we still are wasting a significant portion of bandwidth on broadcasting when the future is point to point communications along with some form of P2P crowdcasting.
>>>

Soooo..... it will take about 1000 times more wireless/cellphone spectrum to do what broadcast TV does in just 300 megahertz. Point-to-point sounds horribly inefficient to me?

Re:The FCC is at fault

[Anonymous Coward]

Sorry smartass, the existing broadcasters were there first. Common law property rights, which would have worked just fine had the government not shut it down.

Re:The FCC is at fault

[aharon]

Good point, libertarian-man. We'll need some kind of cop to protect those existing broadcasters though. How about the FCC?

Re:The FCC is at fault

[Anonymous Coward]

You could make a system where people offer bandwidth from their personal routers for really cheap. I think this does exist, but it's pretty limited in that instead of being offered by one small company, it should be an engineering standard offered in tandem by all the communications companies.

Re:The FCC is at fault

[Anonymous Coward]

Unfortunately people want "on-demand" everywhere nowadays, god forbid that you watch your favorite show at the same time as your next-door neighbor. I prefer the recording solution, storage is cheap and then I am in control of playback.

Re:The FCC is at fault

[vux984]

You could make a system where people offer bandwidth from their personal routers for really cheap. I think this does exist, but it's pretty limited in that instead of being offered by one small company, it should be an engineering standard offered in tandem by all the communications companies.

All those personal routers don't go anywhere except your personal LAN. For people to really be able to 'sell' or even give their own bandwidth they'd need to create a mesh network with their neighbors. (That means running cables between your router and all your neighbors router.) That's simply not going to happen.

Now you can do it wirelessly, but sending any data through a mesh network of wifi access points is going to be pathetic. Dozens of hops, high latency, unreliable connections, and there are security issues too. It would be handy to have, so that our home internet access could route around a fiber cut at the ISP... but it would be a very poor substitute for what you get from your ISP.

Re:The FCC is at fault

[rdnetto]

It only works as long as everyone has 'unlimited bandwidth'

Or as long as people accept uploading as the cost of the content. Torrents work because people are willing to seed to maintain a good ratio, even on public trackers, and that includes people on connections with caps.

Re:The FCC is at fault

[Anonymous Coward]

Good point, libertarian-man. We'll need some kind of cop to protect those existing broadcasters though. How about the FCC?

The FCC is not necessary to enforce common-law property rights in spectrum.

Our Military

[JeffAMcGee]

We could always kindly ask the military to use a little less of the spectrum. I'm sure they really don't need half of the spectrum. What do you think are the chances of that happening?

Re:Our Military

[nloop]

http://en.wikipedia.org/wiki/Ultra_High_Frequency#United_States_2

Doesn't look like the US military uses much of the wireless spectrum... am I missing something?

Re:Our Military

[countertrolling]

They use much higher frequencies

Re:Our Military

[Anonymous Coward]

The military doesn't have exclusive use of much of the spectrum. However, they've got shared use with a bunch of users. And, those users bitch whenever their shared gets shared by the military, even though their contract with the FCC specifically says that the military gets first dibs on it. And yes, spectrum diversity is extremely important in EW. Therefore, it won't work to "take that spectrum from the military" or whatever the hell the current notion is because it's already shared, and there's no good way for the military to not use it.

And yes, I am an electronic warfare specialist

Wireless technology

[Renegrade]

Welcome to the real world of physics.

Wired and optical technologies will ever be superior to wireless, by the simple fact that they're essentially 1D lines running through 3D space, whereas a typical wireless signal is a 3D signal in 3D space - a single frequency gives a fixed bandwidth to a single user in a given ~volume~.

Advanced tricks allow increased sharing, but the fundamental limitations remain.

Consider the volume of a typical wifi base station .. now imagine filling that volume with OC192 cabling. As they say on the "intartoobs", "pwned".

Re:Wireless technology

[relguj9]

Welcome to the real world of physics.

Wired and optical technologies will ever be superior to wireless, by the simple fact that they're essentially 1D lines running through 3D space, whereas a typical wireless signal is a 3D signal in 3D space - a single frequency gives a fixed bandwidth to a single user in a given ~volume~.

Advanced tricks allow increased sharing, but the fundamental limitations remain.

Consider the volume of a typical wifi base station .. now imagine filling that volume with OC192 cabling. As they say on the "intartoobs", "pwned".

Superior in bandwidth and security, inferior in about 100 other ways, mainly the fact that there is a wire involved.

Re:Wireless technology

[CannonballHead]

inferior in about 100 other ways, mainly the fact that there is a wire involved.

I believe that's 1 way. 99 more to go ;)

Re:Wireless technology

[zippthorne]

I wish people would stop pretending that wires are secure enough use unencrypted. It's like they never heard of beige boxing.

Re:Wireless technology

[flydude18]

You're assuming that devices are limited to omnidirectional transmission. What if they were all fitted with tiny phased arrays? It's conceivable that they could keep the beam pointed toward a single base station, and interfere very little with the space around them.

I don't even know if this is a plausible solution to your problem, but it's the first thing that came to mind. I'm not prepared to predict that innovation will stop.

Re:Wireless technology

[Anonymous Coward]

A 3D signal can take advantage of spatial multiplexing. (This is the basic principle behind MIMO.) So surprisingly enough, wireless actually can take advantage of some modulation schemes not available to wired connections.

Anyway, there's no real physical limit to how much bandwidth you can provide, it's more of an economic limit of how many cells you want to build to cover the ground.

Re:Wireless technology

[Comatose51]

If you define superiority as "max bandwidth" then yes wired technologies win. However, if you define it as "most useful" then it isn't always superior. Try serving the number of people who listens to radio with wired connections. Car audio systems would be limited to cassettes and CDs. Imagine trying to fly with a 1,000 km long cable dangling from the plane. Phones are nearly ubiquitous today precisely because they're mobile and wireless. Wires limit your mobility and drives up the cost because you have to laid down a line for each user. Often times those lines aren't even in use. Wireless technology allows you to only occupy the airwaves when it is needed (more or less, discounting the occasional phone home signals). Oh, and you can forget satellite or any form of long distance communications.

As it is often the case in the engineering, the right solution is the one that makes the right trade-offs instead of adhering to some ideology, generalization, or some misguided sense of purity.

Tethering a cable with you device makes the device a non-starter so mentioning wired connection is just pointless.

Re:Wireless technology

[TheRaven64]

Or that they assume that there is only a single hop. I had my password sniffed (a long time ago) because I was using unencrypted POP3 over a modem. At the far end, the server was connected to a 10Base-T network and all of the unencrypted packets were visible to the machines on the same segment.

Re:Wireless technology

[Renegrade]

Beige boxing would be rather hard to pull off against ADSL2+, or my gigabit LAN. Especially the LAN since you'd have to gain physical access to my facilities first.. And every protection that can be put over wireless can be put on wired as well. Just because it's LAN/ADSL2+ doesn't mean I'm telnetting to remote servers.

In fact, if I'm going up against WiFi, I'd have to say that I'm more likely to be using something.. overheady like SSH, than some WiFi user who's wondering why their ISP "capped" them to 200k/sec, who switches to something less secure in a desperate attempt to gain back responsiveness every time the old lady next door heats something up in her microwave..

Oh and regarding the wire being a problem - I don't have much of an issue with my 50 foot ethernet cable that plugs into my notebook. It gives me full LAN speed anywhere in my unit. Also, if you're dealing with a fixed installation, a free space optics system can give you LAN-class (or superior) performance over kilometers, while acting like a wire instead of a broadcast. Full duplex, anybody?

Re:Wireless technology

[MyLongNickName]

You are technically correct. However from a practical standpoint, which is more secure: a home with a small wired network and no wireless and no encryption? Or a home with a wireless network and no encryption? Most folks are not going to try to tap into my wired network to eavesdrop, but any schmuck can war drive and do the same.

Re:Wireless technology

[Anonymous Coward]

I define superiority as "max bandwidth, max reliability, max number of possible users". Just for reference, I'm usually referring to radio when I say 'wireless'. Free-space optics, for fixed installations, aren't too bad..compared to radio at least.

Serving people with radio -> uh, so cable television was a figment of our imagination and never existed? and the PSTN network too?

Car systems -> ever heard of MP3 players? Also, perhaps you should stop listening and start driving.

Flying with 1,000km cable -> Oh wow you found exactly one example where wireless is distinctly better. One whole example!

Phones -> came from the PSTN wired network. Remember that?

Driving up costs -> nooo, satellites aren't hideously expensive. CRTC/FCC licensing fees are free! That big, tall, multi-megawatt tower came free with the huge area of land necessary to support it (also free)! That wireless access point wasn't three times the cost of the wired switch. That one 802.11-N NIC wasn't actually eighty dollars more than a 100/FD ethernet card, which wouldn't totally pay for those sixty dollars of cables you had to buy. Nevermind that the no-name 100/FD ethernet card takes less CPU time and delivers six times the actual bandwidth and cannot be jammed short of a nuclear blast and doesn't have to be updated to WPA2.. or 3.. or 4.. or whatever easily-broken version number they're at now.

Long distance communication -> 98% of traffic goes over undersea cables. Satellites are slow and horrible and bad. Hint: geosync/geostat satellites can't see the other side of the planet, nor equivalent sats above the other side of the planet. Do the math to figure out how much time is added to a signal going from Toronto to Beijing via geostat/geosync satellite. Cheat sheet: Geostat is ~35,700km above sea level. C is ~300,000 km/sec. Before you pull out that misinformed thing about electricity or optical fiber being slower than radio, let me inform you that most electrical and optical wired systems carry signals at 60-70% of C or better.

Trade offs?
Wireless Pro:
- there's no wire.
(Radio) Wireless Con:
- it might cause cancer
- devices are more expensive
- devices consume more power (yah, that WPA2 encrypt/decrpt module doesn't run off of wishful thinking)
- frequency contention is a major problem
- reliability is a major issue
- performance is a major issue
- multi-user access is a major issue
- security is a major issue
- You can't power a device SAFELY from wireless (you can power it though! a nice multi-megawatt focused microwave beam could run your iphone! just.. don't expect to survive)

Sometimes these problems can be waved away, for example my TV remote works fairly well despite all of the limitations, but it's..very, very limited in what it can do.

I'll keep my $30(CDN)-a-month, unlimited incoming and outgoing calls, unlimited anytime minutes landline telephone, thank you very much. Oh it also carries a 8.5 megabit DSL connection..at the same time. There's only about 18.5db of loss between me and the CO on that line too, I don't think you could get a signal that good with a cellphone even if you wired it's antenna physically to the tower.

Get spectrum used by obsolete technolgies

[NoYob]

AM and FM radio. Who listens to the radio anymore? It's either over the internet for "radio" or in the car use MP3s, iPods, or CDs for us old farts. Shortwave? Does anyone actually listen to it? I turned on a shortwave and between huge swaths of static, there was Cuba radio, Canadian News (that can be kinda cool), and a few folks praising Jesus and condemning non-believers (everyone who doesn't give them money).

What always happens...

[rxan]

What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks?

The same thing that always happens: The telecoms cry like babies and the consumers get less for equal or greater cost.

Re:What always happens...

[NotBornYesterday]

What happens? "Traffic shaping" in the form of more caps and deep-packet inspection. For our own good, of course ...

Re:Get spectrum used by obsolete technolgies

[Anonymous Coward]

Aren't those both about 100khz of bandwidth apiece? less? I think you're talking about adding a few dial-up modems worth of bandwidth at the cost of destroying something that's reliable/DRM free with something that's not. IP is not, and was never intended to be, a realtime protocol.

Open Spectrum Access

[abbynormal brain]

I read an interesting argument back in 2000 (the piece was actually delivered in 1995!) and titled "Taking the Next Step Beyond Spectrum Auctions: Open Spectrum Access". Unfortunately we'll be fighting an uphill battle: "Governmental agencies tend to be staffed by lawyers who view a frequency as a unique property right."

amateur radio

[viridari]

You watch, the hams are going to lose spectrum to facilitate commercial interests.

Re:amateur radio

[zippthorne]

There are international treaties to observe. HAM spectrum won't disappear quickly.

Re:amateur radio

[mirix]

Shortwave would be useless for wifi... on a good day, a watt can go half way around the world - that's gonna bugger your signal to noise ratio.

Not to mention low frequencies mean long antennas.

Re:amateur radio

[rcpitt]

OK - so take 30MHz +- 1 HZ and apply 512QUAM to it- then encode via Morse with mechanical bug and automated reception - should get you something like 100 Words/minute, maybe more...

Still faster than I ever got on my code test :(

Re:amateur radio

[viridari]

Amateur Radio != short wave. Amateur radio has spectrum allocations extending well into microwave, and most local traffic is on UHF/VHF spectrum.

Boo to me

[abbynormal brain]

I forgot to provide the link:
I forgot to include the link: http://www.columbia.edu/dlc/wp/citi/citinoam21.html

What about the Spectrum ?

[CharlyFoxtrot]

Yes, all those mobile devices have wireless and yet the venerable Spectrum still has none. No fair !

Dynamic frequency negotiation

[six11]

I'm no radio engineer, but it is my understanding that there's been a bit of work on dynamic frequency negotiation that allow devices to find frequencies that are and aren't being used (or what levels of noise there are). I've just started looking into Software defined radio and the more esoteric (and horribly-named IMO) Cognitive radio that theoretically provides the (artificial) intelligence to perform such negotiation. The theory is that this approach makes more efficient use of the same spectrum while improving communication for those devices because their I/O is very flexible. And, the devices are hackable in software, which is fun for the whole family.

If there are any radio people in the room, speak up.

Re:Dynamic frequency negotiation

[commodore64_love]

>>>allow devices to find frequencies that are and aren't being used

Yeah there's already been tests using these devices on the TV Band. What they found was the device could detect strong local stations, but not the low-level signals from 40 miles or more distance, so they started broadcasting over top existing TV stations, thereby interrupting viewers' reception. The idea was rejected by the FCC in early 2008.

Re:Dynamic frequency negotiation

[Anonymous Coward]

I wouldn't say that I am a radio 'engineer', but I am definitely a radio communications technician/engineer. I believe you are referring to adaptive frequency hopping spread spectrum (AFH) which is a type of keying used to minimize noise with multiple radios using the same spectrum. The key difference between FHSS and AFH is that AFH figures out which channels have the most interference, and change the hop pattern to avoid those channels. A problem with AFH is with interference from multiple FHSS networks in the area; because they are mutually interfering, which defeats the purpose of dynamic AFH.

Re:Dynamic frequency negotiation

[John Hasler]

I believe that they have since been convinced that the study was flawed and are reconsidering.

Economics

[mcrbids]

It's pretty simple, really. If the company makes money on each connection, and reinvests part of that profit, then the service network overall grows more capable. More towers, more frequencies, more bandwidth.

Assuming that the phone companies are smart enough to reinvest a portion of their profits - at my company we invest heavily in growth, and have at any time about 5x-10x capacity headroom, along with fully redundant backup schema for D/R. A few times, we've leaned on that extra infrastructure - while not cheap, it's cheap insurance.

Why would cellular networks be any different?

Re:Get spectrum used by obsolete technolgies

[TikiTDO]

A few hundred khz of bandwidth is quite a bit of data that you could be sending, especially properly compressed/processed/split into segments.

Dynamic Allocation

[John Hasler]

> What happens when we quadruple the number of subscribers with mobile
> broadband on their laptops or netbooks?

You finally admit that it isn't 1920 anymore and give up on centralized static global allocation?

Re:Dynamic Allocation

[zippthorne]

No, you drop the power and use more cells.

Re:Dynamic Allocation

[TheRaven64]

Yup, the future is almost certainly mandating the protocol, rather than the 'owner' of a bit of spectrum. Take each chunk and designate a protocol for it for ten years, on a rolling program so every year or two some spectrum is assigned to a new protocol. Everything using that frequency has to use the same collision detection and avoidance protocol. Anyone found using too much gets a big fine.

Uh no.. try TV

[Anonymous Coward]

Radio takes nothing very little spectrum.

According to the fcc chart AM radio takes about 1 MHz. FM takes about 20 MHz, but that still isn't much compared to TV. It says 18 MHz just for channels 2-4. That's nuts. Don't forget that you transmitters got to space out the channels, at least that's what I hear.

at that rate...

[Garble Snarky]

Does anyone else see a problem with this quote from the article?

"The DTV transition freed the 700 MHz block and increased the available wireless spectrum by a multiple of three, Genachowski estimated. But that took more than five years to complete. At that rate, it would take 50 years to accommodate our wireless data growth. "

the 700MHz block was not deallocated at a constant rate over the course of 5 years... it took five years of political/business BS to clear it. That's not to say that clearing a larger block won't take more time, but there's certainly no reason to believe the relationship would be linear. I think this is a case of a reporter regurgitating words that he liked the sound of.

Shortwave: Numbers Stations: Spies

[PolygamousRanchKid]

Shortwave? Does anyone actually listen to it?

Spies: http://en.wikipedia.org/wiki/Numbers_station

One man's static, is another man's coded instructions.

So you admit to listening to shortwave static and Cuba Radio? What a give-away.

I'm not sure about Canadian News, but I'm sure some charges could be trumped up for you listening to that.

As for the Jesus folks, Bibles make excellent One Time Pads: http://en.wikipedia.org/wiki/One_time_pad

I think shortwave will be around for a bit, even if only spooks listen to it.

Re:Get spectrum used by obsolete technolgies

[compro01]

If you took the entirety of the AM and FM radio space, you'd have about as much frequency space as a single wifi channel, which would be spread over a fairly large area due to the signal propagation properties. Shortwave would be even worse in that respect.

In short, it would not be very useful.

Are Silos The Problem?

[Bob9113]

"'We are fast entering a world where mass-market mobile devices consume thousands of megabytes each month,' FCC Chairman Julius Genachowski warned at CTIA Wireless yesterday. 'So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is? What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks?'"

Is the problem all the silos? Suppose every house with a land-line connection also had a wi-fi hub that was open. I think the bandwidth problem would not exist.

We'd be left with the "how can we profit on this" problem and the "how can the FBI spy on this" problem, but those don't seem nearly as important as the "how can we make information access ubiquitous and fast" problem.

Re:Are Silos The Problem?

[nxtw]

Suppose every house with a land-line connection also had a wi-fi hub that was open. I think the bandwidth problem would not exist.

802.11 based systems aren't good at many things that existing cellular systems are. It doesn't have soft handoffs and doesn't work well when the same network has adjacent cells using the same channel. For 2.4 GHz 802.11, there are only 3 non-overlapping channels.

802.11 can't support devices at the same distances / similar power as modern cellular networks.

Re:Are Silos The Problem?

[Bob9113]

802.11 based systems aren't good at many things that existing cellular systems are. It doesn't have soft handoffs and doesn't work well when the same network has adjacent cells using the same channel. For 2.4 GHz 802.11, there are only 3 non-overlapping channels.

Good info

802.11 can't support devices at the same distances / similar power as modern cellular networks.

If you could solve the first point above, would that be a problem if open hotspots (or something similar) were ubiquitous?

You'd still need long distance for low population areas, but there isn't a spectrum crunch out there. The spectrum crunch is where population density is high -- which is where large numbers of land-line connected wireless repeaters of some sort seem to be able to solve the problem.

Admittedly, this is way outside of any kind of existing feasible business model -- but peculiar new problems seem like a decent place for peculiar new solutions.

I am genuinely curious what you think -- I think it would serve us all well if we could figure out a workable solution.

Re:Are Silos The Problem?

[nxtw]

If you could solve the first point above, would that be a problem if open hotspots (or something similar) were ubiquitous?

If a 802.11-derived network was designed to provide the features of a modern cellular network, it will retain little in common with 802.11. It's not possible to avoid centralized coordination of all access points; otherwise, you'd just be switching between different Internet connections every hundred feet or so.

It's already possible to have low-powered base stations that are connected to a residential Internet connection, though. AT&T offers such a device.

Re:Are Silos The Problem?

[Bob9113]

If a 802.11-derived network was designed to provide the features of a modern cellular network, it will retain little in common with 802.11.

I can live with that.

But I'm guessing that is more to indicate a different problem; 802.11 is the standard, and ubiquity would be most rapidly served by adhering to the standard. Fair enough -- so 802.11 compatibility would be an objective. But if we could only solve the ubiquity problem with a new standard, wouldn't it be worth looking down that path?

It's not possible to avoid centralized coordination of all access points; otherwise, you'd just be switching between different Internet connections every hundred feet or so.

How centralized? As centralized as an ant or bee colony? Could we achieve that? How about smart nodes that know about their thousand closest neighbors and how to handle handoff? How about adaptive nodes that learn the patterns of probable handoff?

Suppose you toss in a server that you use as a proxy. It knows how to chunk large transmissions and parcel them out to your volatile IP address, so you only have to get a few hundred bytes from each node you pass.

It's already possible to have low-powered base stations that are connected to a residential Internet connection, though. AT&T offers such a device.

An interesting concept. How is the market penetration? Does it help solve the bandwidth crunch Genachowski mentions? Does it do better or worse at that than a decentralized solution would?

Re:Are Silos The Problem?

[TheRaven64]

One of the more recent 802.11 protocols (q maybe?) covers hopping from network to network. Not sure how well-supported it is. It's not widely deployed because people are starting to think that it's better to move this up a layer in the protocol stack and use Mobile IPv6, which uses IPsec to dynamically update the routing tables for mobile clients, so they can hop from one physical network to another without any problems. And, sometimes, none of this matters. If I'm sitting in my house or in a coffee shop, I can use my mobile phone (which supports 802.11g and SIP) to make and receive calls without needing to do any hopping. With a decent mobile network supporting IPv6, I'd be able to hop from the WiFi to the LTE network without interrupting my call if I got up and went outside.

Re:Are Silos The Problem?

[Anonymous Coward]

I think those two are the problems that matter in the first place, or why else would they care? :P

Re:Are Silos The Problem?

[nxtw]

But if we could only solve the ubiquity problem with a new standard, wouldn't it be worth looking down that path?

There are standards that already meet the requirements of building a cellular network. They are currently used to build cellular networks.

How centralized? As centralized as an ant or bee colony? Could we achieve that? How about smart nodes that know about their thousand closest neighbors and how to handle handoff? How about adaptive nodes that learn the patterns of probable handoff?

Devices need to know about the adjacent base stations to the one they are currently using. Adjacent base stations using the same channels need to coordinate power levels, and they can communicate using the shared channel. If adjacent base stations aren't using the same channels, they need some way to communicate - either with a separate transceiver on another channel or via a wired network.

But knowing the adjacent base stations is only a small part of the problem. For soft handoffs to work, both base stations involved must be using the same channel, and both base stations need to be sending/receiving the bitstream to/from a given mobile device. This requires a complete overhaul of the way IP routing works (not only a way to change the route to a host quickly, but also to route one packet to two routers, accept packets from one host via two routes, and drop duplicates), or it requires all traffic to go through a central point (which is how cellular data service currently works). That central point needs to be common between all access points that will support handoff between each other, or have a hierarchy where communication can be handed off between a group of access points and the individual access points in each group.

A cellular network might have all the base stations in a large city connected to the same switch or group of switches, and can support handoffs between base stations for many miles. When all of this works as expected, you can travel within a city without losing the session at all. In some cases, you can even handoff to an entirely different network - usually when crossing licensing boundaries.

Handoffs on 802.11 are certainly possible when all base stations are on the same Ethernet, but soft handoffs aren't. Connecting all the base stations in a large area via a single Ethernet is not feasible.

Suppose you toss in a server that you use as a proxy. It knows how to chunk large transmissions and parcel them out to your volatile IP address, so you only have to get a few hundred bytes from each node you pass.

It takes a long time to set up a new session on a 802.11 based network - you have to associate with the AP and get an IP address. For a voice call, this takes too long.

An interesting concept. How is the market penetration? Does it help solve the bandwidth crunch Genachowski mentions? Does it do better or worse at that than a decentralized solution would?

It's brand new, but I think Verizon and Sprint have similar devices. It probably doesn't help very much with bandwidth - the microcell is private and individual devices must be authorized to use it. At any rate, I would expect the worst bandwidth problems to occur away from residential areas - think schools, sports venues, offices, retail stores, etc.

In some places, using the open wifi might not be a good option. During the day, my AT&T 3G wireless Internet connection is sometimes faster than my office's Internet connection. In ideal conditions, the same 3G connection is also faster than a lot of DSL lines. I've seen DSL lines that have a downlink rate of 384 kbit or less due to poor line conditions, and I think some DSL and cable providers still have 1.5 mbit or even 768 kbit download tiers.

Re:Are Silos The Problem?

[SputnikCopilot]

We'd be left with the "how can we profit on this" problem and the "how can the FBI spy on this" problem, but those don't seem nearly as important as the "how can we make information access ubiquitous and fast" problem.

That all depends on who is deeming the importance. If it's the few, massive, greedy corporations who own and maintain the infrastructure while lobbying to create our laws, then "how can we profit on this" easily exceeds the latter.

Re:Are Silos The Problem?

[rdnetto]

It only works as long as everyone has 'unlimited bandwidth'

It would, you've just moved it from the mobile phone lines to the residential landlines. Admittedly landlines do have more bandwidth, but you're kidding yourself if you think that the infrastructure in place is even remotely capable of that, or that the telcoms/ISPs/cablecos are willing to spring for it.

Over Hyped

[angelbunny]

In a congested, high user area wouldn't the telephone companies be able to turn the power down on the cell towers and then add more towers closer together? This way you can get more users in a given space, right?

I admit, I know little to nothing when it comes to radio waves, but I do know back in the 90's pre DOCSIS cable ISPs did not limit their users speed, or at least the ISP I was on. Often times the 'pipe' would fill up. The case and effect was slower bandwidth speeds for me but since it was on the ISPs end it was a high bandwidth / low latency setup aka my ping never jumped up regardless if my max speed was 500kB/s or 100kB/s.

In other words, cable ISPs added tier pricing to make more money not because there was bandwidth issues. If there was an issue with the node being over used they would just add another node aka 10 mile radio for the node now becomes a 5 mile radios for 2 or 3 nodes and then 5 miles down to ...

I know radio is more complicated than that but if it worked and does work for cable ISPs then why can't it work for cell companies as well?

Re:Over Hyped

[Eric Smith]

That's the correct solution, but the carriers will try to grab more spectrum first, since it's less expensive for them to add more antennas to existing cell sites than to build new cell cites.

Re:Over Hyped

[nxtw]

I know radio is more complicated than that but if it worked and does work for cable ISPs then why can't it work for cell companies as well?

Cable companies:

• have almost 1 GHz of bandwidth, although much of it is used for TV. Wireless providers have much less; in some markets, some providers might only have 10 MHz.
• have control of the coax/fiber on their network. If there's a problem that results in increased transmission errors, they can fix it. Mobile providers don't control the space between the base station and the mobile device, and can't tear down obstructions to the signal.
• don't really have to deal with variable signal quality, like mobile devices do. When a mobile device's signal quality drops, error correction must be increased and/or the raw data rate must be decreased.
• don't need to introduce additional latency to better handle errors, and don't need to retransmit dropped frames/packets as often.
• can allocate more channels to data if necessary, especially as analog channels are eliminated and digital channels are moved to SDV.
• can split a node so that fewer customers use the same shared channel(s), and can do so as many times as needed. Cellular providers can't build towers whenever they want.
• can use the same channels on separate nodes with no effect between them. Adjacent cells on (W)CDMA-based networks can share a channel - but this increases the total noise, and will not result in the full bandwidth being available from all given cells. (It also results in reduced power levels, which means poorer service in areas with poor signal strength.)
• don't have to deal with handoffs at all - a DOCSIS modem stays plugged in to the same line, and doesn't physically move to another location. Cellular networks support handoffs, and customers get upset when handoffs do not work.

DOCSIS provides 38 mbit shared downstream iny 6 MHz. In optimal conditions, current HSDPA tech provides up to 14.4 mbit shared downstream using 5 MHz, and real world results will frequently be less than that.

Re:Over Hyped

[ModernGeek]

I wish that I could mod you up. This makes total sense. More lower power transceivers in dense populations, and fewer high powered transceivers in sparse populations.

Re:Over Hyped

[Anonymous Coward]

This is exactly right. By adding more cell sites you can reuse the same frequencies more and increase the bandwidth available to end users. As a bonus this reduces the power levels required at both the mobile end and the tower end. So anyone who fears that there may be a hazard from cell phone radiation should actually be in favour of installing more towers...which of course in the case we are talking of would be more likely to be various sorts of microcells.

For those who are wondering how this works, so long as the wanted signal is of the order of 10 times as powerful as the unwanted signal (from a site reusing the same frequency) then the mobile will lock onto the wanted one. So bearing in mind the square law, so long as you are about three times as far from the unwanted site as you are from the wanted site, you should be fine. This is of course a simplification and ignores lots of interesting effects. This is like capture effect in an FM radio.

scale

[Eil]

'We are fast entering a world where mass-market mobile devices consume thousands of megabytes each month,'

Which is not as bad as a few gigabytes a month. But definitely far, far worse than millions of kilobytes per month.

Re:scale

[Anonymous Coward]

Thank you very much. That needed to be said.

Re:Get spectrum used by obsolete technolgies

[John Hasler]

> AM and FM radio. Who listens to the radio anymore?

I do, among about 230 million others in the US. Americans spend more time listening to FM radio than to Internet radio, MP3 players, or CDs.

> Shortwave?

For "mobile devices"? There are a few problems with that...

> I turned on a shortwave...

One you bought at Best Buy for $9.95? With a loop antenna? A real performer, no doubt.

The facists response -

[Anonymous Coward]

'So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is? What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks?'

Isn't the answer obvious? The providers jack up the price because the resource is "scarce;" all government sanctioned and perfectly legal.

Re:The facists response -

[stuckinphp]

This makes me want to cut myself.

Re:The facists response -

[John Hasler]

Go right ahead. Don't hold back.

Re:Get spectrum used by obsolete technolgies

[commodore64_love]

If there's no radio in my car, what am I supposed to listen to? And before you say "iPod" I don't want to hear the same music over and over. I want to hear new stuff. Also traffic and weather reports ("warning: tornado coming") are nice to have. I like my radio and if they take away both AM and FM, then I'm going to hurt somebody. :-| At the very least leave me AM.

>>>I turned on a shortwave and between huge swaths of static,

What? You need to get rid of that old unit, because they have digital shortwave now. It sounds almost as good as a CD, and still remains popular in Europe, Asia, and Australia.

orders of magnitude

[Anonymous Coward]

"devices consume thousands of megabytes"?! that sounds almost as bad as millions of kilobytes!

Re:orders of magnitude

[izomiac]

It's expressions like that that make me worry for society. If your target audience can't count past 1,000 then what hope is there for them to understand frequency shortage?

Sometimes I think a highschool diploma should have to be renewed every ten years. The recent British study on people's inability to locate their heart convinced me; ignorance is a pandemic now.

Re:Get spectrum used by obsolete technolgies

[commodore64_love]

Okay - FM is 20 megahertz wide and AM is about 1 megahertz wide, so we're talking the equivalent of 3.5 television channels.

According to the ATSC spec, that's just 70 Mbit/s of datawidth.
According to the HDR spec, you get 300kbit/s per 0.2 spacing, or about 32 Mbit/s.
Trivial.

Demand management

[PPH]

We'll fix the problem by keeping all those toys off the air much of the time. Laws will be passed such that if you so much as look at a wireless device while driving, it'll be confiscated.

There. Problem solved.

We'll wish we had standardized.

[strangeattraction]

What is going to happen? We will wish that we had standardized on gsm or something so that we could get the most efficient use from the spectrum. Congress's rush to sell spectrum for a windfall will come back to haunt us. This is what happens when policy makers don't really understand what they are making policy about.

Re:We'll wish we had standardized.

[nxtw]

What is going to happen? We will wish that we had standardized on gsm or something so that we could get the most efficient use from the spectrum.

Not really. Old GSM is horribly inefficient compared to WCDMA or CDMA, and simply using the same technology won't make all the providers decide to build one big wireless network or allow roaming between any network at any location.

At any point in the past 6 years or so, there have been 2-3 GSM networks and 3-4 CDMA networks in my area. The GSM phones are technically capable of working on any of the GSM networks, and the CDMA phones are technically capable of working on any of the CDMA networks. But in most cases, customers can only use the network they subscribe to. Back when I had a T-Mobile phone, I'd often see "Emergency Only" or a similar message with maximum signal strength, because T-Mobile's signal was too weak to be usable and they did not allow roaming on AT&T or Cingular's GSM networks.

Spectral efficiency is always increasing

[Anonymous Coward]

Frequency division multiplexing (dividing up information into "bands" of frequency) is only one way to slice up space/time/etc. There are many ways to stuff more bits into a given frequency band such as using multiple receiving antennas to increase the signal to noise ratio, use of better 1/0 encoding schemes, and so on. Another possibility is the use of the polarization property of light. Stuffing two different data streams on the same frequency at opposite circular polarizations is really simple to do, both sending and receiving. Further slicing of the polarization is possible, as well, so there's plenty of room in the spectrum yet.

Re:Get spectrum used by obsolete technolgies

[TikiTDO]

Sure, it's trivial to calculate what we can do using older techniques, but how does that relate to whatever spec is going to be rolling out in 2019, when this might become more of a problem? After all, a bit of time on Wikipedia, both of these specs were developed in the 1990s.

And since we're on the topic, why did you not bring up the 802.11n protocol, which can accommodate 288 Mbits/s in a 20 MHz channel?

Add more Channels

[Anonymous Coward]

The FCC could, if it wanted to, give 8 channels from the old analogue TV space back to the public at large, for the benefit of the public. I know, a novel idea. We could then supplement the cells phones with this, instead of the nasty microwave popcorn leftovers that is wifi, and with an additional rule, like to, if you want to run a base station at more than 2 watts, you have to provide free internet access. Add in meshing, and we'd even have something that could help emergency responders and the general public in situations like large earthquakes.

No scarcity with the right technology

[Anonymous Coward]

Anyone know about UWB? Ultra wideband radio. Supposedly it can use the entire spectrum without interfering with itself or other radios on any frequency. Any device that can do that has all the bandwidth available because it can use the entire spectrum - so, there is no shortage of spectrum if this technology was unleashed. However, UWB has been regulated so it is underpowered because the regulators were afraid it would make the regulatory regime redundant, and hence render the world's most valuable commodity (spectrum) a non-cash cow. The FCC argued that the technology would cause airplanes to fall from the sky - like cel phones on airplanes. Can't blame them for regulating it into the background because any technology that can end a system that creates artificial scarcity is revolutionary - a paradigm shift. Problem is, we don't make the decisions. I believe you cannot stop technology from advancing, and someday we will not have to worry about lack of spectrum because UWB or its kin will eventually make it a moot argument.

yes: by broadband over power lines

[epoxide]

Someone upthread mentioned that mobile devices won't interfere with amateur radio because of the inconvenience of carrying around a 100ft antenna ... any guesses on what you've made when you send broad spectrum RF signals through all of the power lines in a neighborhood?

Re:Get spectrum used by obsolete technolgies

[Rising Ape]

Millions of people listen to FM radio. Sheesh, are slashdotters experiences of people really so narrow that that you assume that the geek segment of the population is the only one? Yes, let's get rid of that to add a tiny amount of extra space for people to watch Youtube videos on their mobiles.

There's a better case for re-using the old analogue TV spectrum, but only because it's been replaced with a functionally equivalent but more bandwidth-efficient system. Broadcast radio hasn't.

Obvious...

[Twigmon]

Massive wi-fi mesh? In fact, India already does something very similar for a very long time.

Isn't it great that so many of our mobiles already have wi-fi hardware!?

Re:Obvious...

[klapaucjusz]

Massive wi-fi mesh? In fact, India already does something very similar for a very long time.

Reference needed?

I'll tell you what happens....

[joocemann]

Networks start to clog up and Americans will start being fed b.s. about 'needs' to manage network traffic despite the horrible scope of network bandwidth/proliferation in the US relative to other industrialized nations, namely Korea/Japan.

ISP's stated they could double bandwidths at the cost of $6/home, but that option is easily avoided at the benefit of saving $6/home and blaming straw men.

"thousands of megabytes"

[bill_mcgonigle]

Isn't that why our government just auctioned off billions of dollars of our publicly-owned spectrum?

The department that manages that spectrum is apparently run by somebody who has yet to discover the term "gigabytes". What could possibly go wrong?

Re:"thousands of megabytes"

[TimTucker]

Don't worry, it's just a ploy to distract the masses from realizing just how pitifully small 5GB/month mobile caps on bandwidth are.

Re:"thousands of megabytes"

[ShakaUVM]

5GB/month should be good enough for anyone.

Handoff how many times per minute?

[tepples]

If you could solve the first point above, would that be a problem if open hotspots (or something similar) were ubiquitous?

Good luck solving soft handoff for a bus traveling at 45 km/h or 30 mph. It's the same reason cell phones don't work well on planes: they pass over too many cells per minute.

Re:Handoff how many times per minute?

[Bob9113]

Good luck solving soft handoff for a bus traveling at 45 km/h or 30 mph.

You have a good point.

So then, how would you solve it? Forget luck -- we're Slashdotters, a fair bit smarter than the average bear -- how would you do it?

Three quick ideas: Caltrain, smart roads, and start with what you can solve.

Caltrain (like many public transit systems) has wifi on board (I think -- one of the ones around here does -- I walk to work). So for mass transit, there is a mobile solution out there that is already working.

The smart roads side I am not as sure on, but the rough idea is that you can predict with some degree of certainty where each device will be for the next thirty seconds -- at least on major roads. Suppose you combine predictive handoff with wifi node federation -- maybe make them adaptive so they learn handoff flow probability. Would that remove a lot of the problems?

Finally, consider how far "ubiquitous" really needs to go. Suppose we started with the limitation, "As long as you're traveling slower than a quick jog." That would still be a pretty big step forward.

Re:Handoff how many times per minute?

[js_sebastian]

Good luck solving soft handoff for a bus traveling at 45 km/h or 30 mph. It's the same reason cell phones don't work well on planes: they pass over too many cells per minute.

I once got an SMS from the operator welcoming me to switzerland, just because I was flying over the country at 10000 meters altitude...

Re:Handoff how many times per minute?

[nxtw]

Caltrain (like many public transit systems) has wifi on board (I think -- one of the ones around here does -- I walk to work). So for mass transit, there is a mobile solution out there that is already working.

The access point moves at the same speed and in the same direction as the users - and therefore has no handoff issues.

The smart roads side I am not as sure on, but the rough idea is that you can predict with some degree of certainty where each device will be for the next thirty seconds -- at least on major roads. Suppose you combine predictive handoff with wifi node federation -- maybe make them adaptive so they learn handoff flow probability. Would that remove a lot of the problems?

Knowing where the mobile device might be in the near future won't be very useful without some sort of dynamic IP routing or a replacement/overhaul of the Ethernet part of 802.11.
Without soft handoffs, service quality would be very poor for even a slow moving vehicle. A vehicle moving at 20 mph moves at 30 ft/sec. A typical mobile device might enter the range of an access point, reach the point where the signal strength is highest, and leave the range of an access point within 100 ft of travel. It would essentially have to switch networks every 2 or 3 seconds. Without soft handoffs, this will result in an interruption on a voice conversation every 2 seconds or so... unless huge buffers are used, but this would result in a huge delay.

And implementing soft handoffs in 802.11 would probably require major changes in the way 802.11 works.

Finally, consider how far "ubiquitous" really needs to go. Suppose we started with the limitation, "As long as you're traveling slower than a quick jog." That would still be a pretty big step forward.

That is a step backwards from existing mobile networks, which are already designed to work from devices moving at highway speeds.

In addition, those who are walking or jogging probably aren't using a whole lot of data, unless they're streaming audio (in which case existing wifi technology might be OK, because the device can easily buffer many seconds of audio.) Voice congestion on current mobile networks isn't such a big deal. Those who are stationary will have no problem using a single wifi connection. Those who are using public transport will need something that will work for a few miles at higher speeds.

UWB

[reiisi]

Or, it should have been UWB, but Intel had to get their egos all tangled up in things and screw that one up.

Re:UWB

[John Hasler]

I think that the regulatory agencies are the primary barrier to UWB. It threatens their power.

carrier frequency

[reiisi]

Go take a look at bandwidth versus carrier frequency.

Re:carrier frequency

[wooferhound]

Yes there is Ham Radio Television
it's called Amateur TV
http://en.wikipedia.org/wiki/Amateur_television

security?

[reiisi]

security is not unimportant.

carrier frequency

[reiisi]

It really doesn't make sense to trade the FM for digital. Carrier frequency isn't high enough to be of much use.

I'm rather depressed at the whole TV debacle, too. There should be room for analog TV within our culture/society. Maybe HAM?

Hello?

[plastick]

The way it's supposed to work is the companies have more customers, which means more money, which means they expand the infrastructures. I mean, it's not complicated. This is business 101 stuff here.

Re:Hello?

[mister_playboy]

They'd prefer to keep adding customers and not spend a penny on infrastructure, since that's more profitable.

Re:Hello?

[John Hasler]

You can't build more spectrum.

Re:Hello?

[John Hasler]

And that's what they should prefer, but they will build more infrastructure when it becomes necessary in order to add more customers and profitable to do so.

Re:Get spectrum used by obsolete technolgies

[commodore64_love]

>>>older techniques, but how does that relate to whatever spec is going to be rolling out

Alright. Well technologies improve, yes, but there's still a physical maximum imposed by our universe. 21 megahertz == ~330 Mbit/s according to Nyquist's Theorem. So killing-off AM and FM would free-up enough bandwidth to serve three maybe four users.

Re:Get spectrum used by obsolete technolgies

[commodore64_love]

>>>There's a better case for re-using the old analogue TV spectrum

The old analogue spectrum has already been reassigned for use by digital TV. It isn't available.

WiFi Hotspot@home should be universal

[Michael G. Kaplan]

T-Mobile offers a service called Hotspot@home whereby a WiFi enabled cell phone will automatically receive and place calls over your home WiFi. This would enable everyone to make and receive limitless free phone calls while at home and subsequently shift a lot of the burden off of the cell phone network, and everyone would have perfect reception in their house.

This should also be a free service included with every cell phone plan - it is only because of the cell phone oligopoly that T-Mobile is able to charge you a monthly fee for the right to NOT use their network, and similar abuses explain why other carriers won't even allow this option. We need network neutrality.

Re:WiFi Hotspot@home should be universal

[nxtw]

This would enable everyone to make and receive limitless free phone calls while at home and subsequently shift a lot of the burden off of the cell phone network, and everyone would have perfect reception in their house.

The main issue here isn't voice coverage but data service. Voice uses very little bandwidth. I think today's networks use codecs which compress voice to 4-12 kbit/sec.

Not only does T-Mobile typically have less spectrum than their competitors, they still have many customers on GSM, which puts them at a huge disadvantage over the other major providers who have many or all customers using (W)CDMA. Therefore, T-Mobile has much more of an incentive to move phone calls off their network.

This should also be a free service included with every cell phone plan - it is only because of the cell phone oligopoly that T-Mobile is able to charge you a monthly fee for the right to NOT use their network

T-Mobile is providing a service when you do this; it's not free for them. The call is transmitted over an Internet connection (that you are probably paying for) to a T-Mobile system which connects to their mobile network and then to the telephone network. For outgoing calls, T-Mobile pays for the call over the PSTN as well.

Re:WiFi Hotspot@home should be universal

[cdrguru]

I currently have that T-Mobile plan. It is extremely short-sighted of them and will eventually mean the end of T-Mobile (aka Deutsch Telecom) because of how it works.

I have a wireless router at home, the daughter's house, at the office and pretty much have access whereever I go. The only time I am using the cell service minutes, of which I pay for only a very few each month, is when I am in a car.

Sounds good, right? Except each and every call I make costs T-Mobile money. I would say that no matter how little this cost is, it means that I am costing way more than the $200 a month I pay for five phone lines if I make hundreds of calls. So they are losing money every month on my service.

Repeat for probably 20% of their subscriber base. This is insanity. It sounded cool but turning this on was silly and does nothing but cost them money. I think they were betting on people not having access to wireless connections everywhere they went and the $10 a month they charge for the option would easily pay for the few phone calls placed. This is no longer the case as I can save hundreds of dollars in cell service billing by buying a $50 router. So can every other T-Mobile customer with a phone that supports this.

No, it doesn't work very well for the company. I'm sure they are going to turn it off eventually. It certainly isn't a model for anyone else to emulate.

Sounds like a solved problem...

[colinnwn]

I think AT&T CEO Ralph de la Vega and FCC Chairman Julius Genachowski need to go out for a few drinks and talk shop. I'm sure Ralphie can give a few good suggestions...

Re:It's 1996 again?- Collisions

[tetsukaze]

Lets not forget a very important factor. I would love some RF guy to correct me, but radio is like the good old hub days. The air is a shared medium. You throw signals in the air, they will interfere with each other. More towers in this case does not equal more bandwidth, it equals more interference. This is where we need some leap of technology where we can cram more data into smaller channels.

Re:Get spectrum used by obsolete technolgies

[amRadioHed]

He's not assuming the geek experience is the only one, he's assuming his experience is the only one. I'm as geeky as any of us here and I listen to FM radio all the time in my car. I don't know anyone who doesn't listen to it still.

Profit gap

[AHuxley]

Just let US consumers stay in the rust belt of wireless tech.
They still love to say their networks are number 1 in the world.
Thankfully for the telcos this is not a consumer driven problem.
The US telco herd is still intact and cash stream is flowing.
The problem is device flow from Asia and Apple, MS and other designers sourcing Asian chip sets for storage, vid and memory for sale in the USA.
The telcos have tried a tricks with payments and limits, but device envy is building.
They should have rolled out more backhaul, invested in tech.
They sat around enjoying the profits and keeping others out.
Now they want to blame physics?
They where greedy, short sighted and the gov did not set any targets for tax breaks or nation building.
You had bad networks with old tech sold and combined.
Now its all catching up.

Re:It's 1996 again?- Collisions

[Idiomatick]

Of course that is the case but I would do so with radically less power. Instead of ramping a tower up to have a strong signal for 30miles maybe a 1/4mile. While there of course would be more interference it would be manageable. Compared to a hub ... instead of having a few giant ass routers I suggest having hundreds of tiny hubs which would reduce the collision issue. Not the perfect analogy but I hope you get my drift.

Re:Get spectrum used by obsolete technolgies

[Anonymous Coward]

If there's no radio in my car, what am I supposed to listen to? And before you say "iPod" I don't want to hear the same music over and over. I want to hear new stuff.

Uh, have you listened to radio stations lately? Same songs every day and if you listen to the same station long enough you will even hear the same songs several times in the same day. No thank you. I would rather just turn it off and think about things or engage my passengers in conversations.

Electromagnetic spectrum isn't defined by Kb/s

[Myrcutio]

I am not a physicist, but it sounds like you're mixing up analog approximations with digital bandwidth measurements. The frequency of EM spectrum used is determined by the accuracy of resonance on a conductor (see Radio Tuners). There's no reason an antenna can't have any electric length (see Antenna resonance) to read whatever range of spectrum might be available, and the only physical limitation is in how accurately we can transmit and receive those signals. To say that an analog medium has defined universal limits and that no technology is capable of using it more efficiently sounds like a BS assertion, i think you should cite some sources for a claim like that.

Re:Electromagnetic spectrum isn't defined by Kb/s

[PeterBrett]

To say that an analog medium has defined universal limits and that no technology is capable of using it more efficiently sounds like a BS assertion, i think you should cite some sources for a claim like that.

The Shannon-Hartley theorem states that if you have a channel with bandwidth B (in this case, let's say 8 kHz), with additive white Gaussian noise giving a signal-to-noise power ratio of S/N (let's be conservative and say 20 dB), the maximum information capacity of the channel C is given by:

C = B log (1 + S/N)

where the logarithm is taken base 2 to give C units of bits per second. With the numbers above for the analogue channel, this would provide an absolute upper bound on information capacity of C = 53266 bps. Using modern coding systems (LDPC, for instance) it's possible to approach that limit.

An analogue medium does indeed have universal information capacity limits. As any physicist (or electronic engineer, for that matter) will tell you, not only is the analogue bandwidth available usually fixed, but also improving SNR is really, really hard. It doesn't get easier when you're trying to simultaneously make the hardware as small and as power-efficient as possible.

The GP did not make "a BS assertion"; like many /.ers, you really should check your facts before calling someone out like that.

Re:Electromagnetic spectrum isn't defined by Kb/s

[commodore64_love]

>>>To say that an analog medium [space] has defined universal limits [186,000 miles per second] and that no technology is capable of using it more efficiently sounds like a BS assertion, i think you should cite some sources for a claim like that.
>>>

I edited your sentence, because that's essentially what you're saying. You are in denial of basic facts - the universe DOES place limits upon human beings. The radio spectrum DOES have a "speed limit" on how much data can be squeezed in each XX megahertz-wide channel.

Re:It's 1996 again?- The last mile

[tetsukaze]

This then seems to be the same issue that traditional land based providers run into. It costs a good chunk of money to spread out that way. One of the huge gains of wireless being that the last mile is over the air and essentially free. Note: I'm not trying to be a kill joy here but it seems these companies haven't gone this route already and I think this is the reason.

Re:Get spectrum used by obsolete technolgies

[Anonymous Coward]

Use your head. Tailgate that oldsmobile with one of them WMD subwoofers.

interesting.

[SinShiva]

Notice how the amount of initiative a US government program takes to solving a problem is inversely proportional to the amount of revenue companies 'influenced' by said program generates ?

Less scare tactics, more results. kthx.

Obligatory Dr Stranglove

[Agent of Nowhere]

Mr. President, we must not allow a wireless spectrum gap! I... I don't know exactly how to put this, sir, but are you aware of what a serious breach of security that would be? I mean, he'll see everything, he'll... he'll see the Big Switchboard!

Obvious solution to wireless data woes

[zmollusc]

Disk space is pretty cheap. Just equip every laptop/phone/whatever with a Tb or two of built-in pr0ns and arrange a system that updates the pr0ns while the device is plugged into the wall to charge up.

Wisdom of crowds fail

[Kohath]

Every single modded-up article misses the simple answer to the question.

What happens as more mobile subscribers are added? You get congestion. Then the provider adds another base station and the capacity is doubled. Repeat as needed.

But aren't base stations expensive? Yes. But base stations are much like any other electronic device. It's cheaper to build them out of discrete components when you only need a few expensive units. When you need many inexpensive units, you integrate the functions on a chip and manufacture it for $4 (plus some other costs, plus $50 million in engineering amortized over the total number of chips sold in the product lifetime). Then base stations are cheap and can be plentiful, supporting many, many high-bandwidth mobile phones. There's an upper limit, but it's pretty high.

Re:It's 1996 again?- The last mile

[Idiomatick]

I bet it'll be cost efficient when we start running out of spectrum. And yeah I agree it be expensive but much of the last mile is already in place all the infrastructure is there they just need to stick in wireless routers. The last 1/4 mile is a lot of the cost as well, wires to the houses and this would be dropped. Wire was put in before wireless existed. And wireless has been steadily increasing bandwidth. Also the demand for wireless is increasing at a pretty insane price, that demand will make it a necessity to do this.

Niquest !=

[jimmydevice]

If a signal is low-passed to 4 KHz, Yes it's a 4 KHz "audio signal", but it's still running at 64Kb and delivers 56Kb of data. Voice isn't random noise, but modems are.

Re:It's 1996 again?- Collisions

[Gandalf_the_Beardy]

Not quite. More towers equates to smaller cells, which equates to less power needed from the handhelds. By redcuing power output you obviously reduce range. As long as you are within reach of the cell tower that doesnt matter, what it does do though is reduce the noise level and hence the interference.

Read first, post second

[dtmos]

When the GP wrote

The limit isn't in the line itself, it's in the endpoint. ADSL sends a signal through the line that gets received by special hardware sitting before the telco phone equipment which handles a much higher frequency range.

what did you think he had in mind?

You two are in agreement.

Microwaved Popcorn?

[myspace-cn]

"So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is?"

The answer is simple microwaved popcorn!

Clean air at last!

[AliasMarlowe]

90 GHz? at that freq why bother? the freaking air pollution would block the signal over the distance of a large room.

Finally, a motivation to clean up the air we breathe!
Or perhaps to remove the atmosphere completely, so wireless can deliver even higher bandwidths...

the same thing

[nimbius]

i would guess thats been happening ever since we realized the infrastructure behind the spectrum is too old to keep pace with the traffic. Throttle it and let your subscribers eat cake!

FCC is wrong. Its power that matters. Low power.

[knobsturner_me]

The FCC person is wrong. Flat wrong.
Without new bandwidth being opened up he is wrong. Essentially, the amount of data that can be transmitted over say a city is determined by two things:
1) The frequency bands available.
2) The power of the transmitting device. The lower the power the more bandwidth we have. By factors of millions.

So in the old days (like now), a single TV channel covered a city, and gave 6 Mbits (or whatever the rate is) for the whole city. ie close to zero. The transmitter is 100,000 watts.
Now, imagine two 0.01 watt transmitters on the same channel. You can have literally millions of these pairs using the same channel in the same city, since they only have a range of say 100 m. The result is millions of times the bandwidth, along with lower powered devices.

Chips that do exactly that are being developed now. Its sort of like the ethernet protocol, in ethernet, the channel just wait for blank air time on the wire, while with devices, they just look for clear frequencies. Combine that with advances that use reflections and ghosting to improve signal, and you have an era where wireless wins.
Wires will still be handy for backbone, etc. Perhaps even one to your house if its easy.

It really is the power thats the factor.

Re:Get spectrum used by obsolete technolgies

[Veretax]

I honestly don't have a clue how you got moded 5 Insightful. Lots of people listen to Radio, whether for news talk, music, sports, weather, current events. I listen regularly in the car, because I am not always in a music mood. Remember just because you have converted and switched to top line MP3s, Ipods, or Satellite radio, doesn't mean everyone else has. Some of us like what we get currently. Football games in particular I often have to listen to online. Now this may not be the same sort of thing in a more urban setting, but in rural areas, where TV hasn't been saturated yet, FM and AM are the way to go.

Re:It's 1996 again?- The last mile

[commodore64_love]

Wow. Cell towers every 1/4 mile. That will be attractive. Might look something like this:
http://pro.corbis.com/images/IH172885.jpg?size=67&uid=77B92ED2-843B-4F46-9484-2496E45AE139 http://farm3.static.flickr.com/2071/1943018955_52100c0f4d.jpg

Why would we want our modern 2000-era cityscape to look like something from the late 1800s cityscape?

Re:FCC is wrong. Its power that matters. Low power

[SuiteSisterMary]

Actually, your reference to Ethernet is pretty enlightning.

Back when each client was connected to One Big Hub, speeds sucked. To improve the speed of Ethernet, the easiest and backwards-compatibleist thing to do was to invent a switch; each client gets it's very own hub.

Seeding the area with picocells does much the same thing.

Re:It's 1996 again?- The last mile

[Idiomatick]

Lolllll to get 1/4 mile range and enough bandwidth for the area you need something that we can stuff into the already existing switch boxes for neighborhoods. There would be 0 effect. WTF do we need huge towers for if they only need a quarter mile range? Hell my N class home router can almost do that and it cost 50$ and is about 8x10x3cm. And the wiring is already all there. Ok ok my router does more like 50m instead of 400. But still I'm sure this is doable either way. 10x the range isn't crazy for signals.

Cool pics though, the 2nd one looks like Japan. They run tons of wires and do it all on posts rather than underground, that's why they can upgrade their infrastructure so easily.

Cell phones vs. wireless VOIP, why?

[cenc]

Someone who is smarter than me, please enlighten me to why we are not converting cell networks in to simple wireless networks and loading them up with VOIP services, other than the need to screw people out of multi-year contract? Why is there no wireless mesh networking just outright replacing cell towers everywhere?

wifi g - n signals (I am sure we will have better to work with someday) can be beamed a hundred miles, the technology is relatively cheap and robust (as in make in your basement cheap and robust). Why are we still goofing around with cell towers? Hell, why do we even have cell phone companies?

All the technology exists, is tested, and works. It just needs to be deployed.

Re:FCC is wrong. Its power that matters. Low power

[John Hasler]

> Chips that do exactly that are being developed now. Its sort of like the
> ethernet protocol, in ethernet, the channel just wait for blank air time
> on the wire, while with devices, they just look for clear frequencies.

But the FCC exists to allocate the "scarce public resource" of spectrum. Your proposal weakens it.

Re:Get spectrum used by obsolete technolgies

[CompMD]

You just made me imagine a beautiful thing: a hipster slashdotter on his way to Starbucks in his econobox car gets stuck in traffic listening to his iPod (because radio is SO 20th century) and gets sucked up by a tornado and blown into the stratosphere. Kind of like mother nature doing a service to mankind. Thank you sir. Thank you.

Solution

[Anonymous Coward]

The solution is to combine messages. CyAeNs YyOoUu RcEaAnD. THIS?

It will require greater cooperation amongst carriers and some sophisticated planning/development, but the end result will be much more efficient use of spectrum.

An example of the cooperation required will be for consumer devices to use a voting algorithm to assign a leader, and then communicate over a lower-bandwidth signal in the local area to combine their data transmissions.

But that's already needed. We need a home wireless standard that allows the mobile device, game console, television, receiver, cable box, computer, toaster, refrigerator, thermostat, ceiling fan, baby monitor, etc. to communicate and allow controlling from one another, along with a security/role system that allows for access control to each.

Until the idiots that control the means get their heads out of their asses we're stuck with half-assed solutions to everything because they can suck more money out of us. We could be living 20 years into the future in 5 if we'd stop being such babies about everything and start cooperating. It's game theory: if everyone plays cutthroat we all have to move more slowly and take less gain.

Won't be a problem...

[drbuzz0]

We have gotten used to the idea that the government needs to solve problems (something that it is very bad at) due to the recent administration. The fact of the matter is that the wireless market is very competitive and a lot of money is spent to keep customers by improving systems. Whatever is required to keep bandwidth up, whether it be smaller cells, more advanced modulation, MIMO, more bandwidth sharing etc etc will be done. The companies can't afford not to and they are all already upgrading their systems and planning for future upgrades. If they don't and the system bogs down, people will go elsewhere. The company with the best mobile service will always have a competitive advantage.

We don't need to do anything. Just sit back and let the market take care of it. The government just needs to leave it the hell alone. In the late 1990's, the government decided to meddle with the lending markets to try to encourage more first time buyers to get good rates on loans. They changed the subprime markets and introduced incentives to take on high risk credit. Look what happened! There is only one way that the spectrum will become a problem: if the government starts getting its meddling hands all over it.

Not as big a problem as it sounds

[Jimmy_B]

This is not nearly as big a problem as it sounds like, because it has a simple engineering solution. A transmission of a certain speed always uses up the same amount of bandwidth, but it uses that bandwidth over a different area depending how far it is from the cell tower or access point. The farther away the access point is, the more power the tower and phone use, and the more area the transmission covers. Placing more access points closer together allows lower-power transmissions, so that the same frequency can be reused more times in different places. So if there isn't enough capacity for all the people using the cell phone network, you just put up more towers. It's expensive, but not so expensive that normal subscriber fees can't cover it.

Brillant Idea!

[Bishop077]

Next lets give the public standard issue pitchforks and torches. Then we can start burning witches like the old days.

Re:Brillant Idea!

[Bishop077]

Doh! wrong story Ignore this

Re:Get spectrum used by obsolete technolgies

[Anonymous Coward]

It could still be useful for QAM. Just because AM & FM are the current use, doesn't mean there aren't newer modulation schemes.

Spread Spectrum

[jweller13]

Does the use of Spread Spectrum reduce any of the spectrum saturation problems.

Re:Get spectrum used by obsolete technolgies

[SputnikCopilot]

If there's no radio in my car, what am I supposed to listen to? And before you say "iPod" I don't want to hear the same music over and over. I want to hear new stuff.

Do you listen to FM radio? ClearChannel has ensured that every station is the same music over and over, commercials are synchronized between stations, and "new stuff" isn't necessarily "good stuff". My 16GB (non-iPod) player holds more music than I hear repeated in a week over the local FM station always playing in the office. Still, I'm all for FM staying around (so long as as there is public radio for NPR and the likes), but I don't think we have to worry about its demise anytime soon.

more caching won't work

[Anonymous Coward]

because the wider you throw something, the less possible it is to keep it secret.

And when your business is "intellectual property", you HAVE to keep it secret.

Why?

[Anonymous Coward]

Your gigabit copper is also a big ol' antenna. It can be sniffed from arbitrary distances away with sufficiently directional antennas.

Beige boxing always requires physical access, by definition. I really fail to see how it would be harder to beige box your adsl (which is a service provided by the telephone company over telephone lines) than just your voice phone (which is a service provided by the telephone company over telephone lines). The intercepter has the advantage over the phone company of being much, much less than 10,000 ft. from you.

WiFi does not have any illusions of being a secure medium (although CDMA spread spectrum would probably be good enough for a lot of purposes). So there are workable encryption schemes built right into the protocol. Because it's obviously less secure, people are more likely to bother to properly secure it. If people actually used encryption over their wired lines, then it would be good enough. Fortunately, at least, SSL is in common use for actual commerce.

Re:Why?

[Renegrade]

A sufficiently directional antenna doesn't exist. Even if it did, it wouldn't be able to track with the vibrations from the power fan in the system moving the wire ever so faintly as it would be TOO directional. Plus, it's in a bundle of about twenty lines. Good luck! (especially good luck as it's transmitting both ways on all eight wires simultaneously using heavy duty echo cancellation at a frequency that's a harmonic of 802.11, that'll be fun to receive on the other end! Wires, by the way, which are twisted around each other to cancel out the signal..)

The ADSL2+ signal goes to a media converter in my basement. The interceptor has to be INSIDE MY SECURITY PERIMETER, at which point they're already arrested. It's fiber optics past that point. Good luck finding a listen-only ADSL2 device. And it's SSH underneath all of that physical protection for anything remotely important. Good luck with that too!

I, am, on the other hand, surfing around the various open, WEP, or WPA based access points here (using my laptop, in default configuration, without any additional hardware, without physically visiting restricted areas). Apparently wireless isn't 'obviously less secure' enough. I'd like to see someone catch me too, if I'm just listening to packets, instead of performing B&E on telco or personal property and planting various kinds of wiretapping devices...