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Germans Reach 360 Mbps in Mobile Network Tests

povvell writes "German telecomms giant Siemens has managed to hit speeds of an astonishing 360 Mbps in field tests in the centre of Munich using 'orthogonal frequency division multiplexing (OFDM) and the so-called multi-hop technology'. This is not the only demonstration of OFDM producing super fast wireless speeds, as other companies are also working on variants of the technology. It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

134 comments

  1. This will help them by Anonymous Coward · · Score: 5, Funny

    Distribute full length David Hasselhoff movies in mere seconds! Fear!

    1. Re:This will help them by aneurysm36 · · Score: 1

      yeah, michael knight flying down the information autobahn
      ba-da-BOOM

      --
      ------ hi mom
    2. Re:This will help them by Anonymous Coward · · Score: 0

      you can already since they do not contain a lot of information they must compress amazingly well ;)

  2. How much "radio pollution" would that produce? by Cprossu · · Score: 5, Interesting

    360mbps seems like alot for wireless, considering the mess 108mbps (by using 2 different spectrums) created, what would a multiple dynamic frequency wireless setup leave us...what happens when you have 50+ different networks together?

  3. Surely can't be long by gonerill · · Score: 4, Funny
    It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"


    Not long at all. And about ten minutes after that, the two RIAA agents will enter the carriage with an alsatian, escort you off the train at the next station and you will never be heard from again.

    1. Re:Surely can't be long by aussie_a · · Score: 1

      1> I think you meant MPAA. 2> Whose to say it won't be legal? Oh I know it was a joke, but it wasn't a very good one.

    2. Re:Surely can't be long by Xaoswolf · · Score: 1

      I'm picturing two RIAA goons on a hand cart trying to keep up with the train...

    3. Re:Surely can't be long by DriedClexler · · Score: 0

      And they'd be totally justified in doing so. This new technology is just going to make the p2p filesharing problem a zillion times worse and is going to destroy literally all incentive for artists to produce movies and music.

      --
      Information theory is life. The rest is just the KL divergence.
    4. Re:Surely can't be long by WhiteWolf666 · · Score: 1

      Two goons on a hand cart in front of the train, demanding that it stop.

      --
      WhiteWolf666 an exBush supporter. All you new-school,compassionate,save the children Republicans can rot in hell
    5. Re:Surely can't be long by javiercero · · Score: 1

      Silly me, all these years thinking the main incetive for an ARTist was the ART.

    6. Re:Surely can't be long by bfischer · · Score: 1

      They were talking about blockbuster movies, not art. The two are pretty much mutually exclusive, right?

  4. Raw stats on movies... by strredwolf · · Score: 5, Informative

    Okay, let's get some raw movie stats. Assume plain RGB pixmap flipping at 24 frames per sec, movie size. That's 720x480, three bytes per pixel.

    That's about 1 Megabyte a second, or 8 Megabit. Add another 256 Kilobits/sec for audio (Mp3, Vorbis, or AAC, anyone?) and that's 10 Megabit and change.

    Isn't Divx compression good?

    --

    --
    # Canmephians for a better Linux Kernel
    $Stalag99{"URL"}="http://stalag99.net";
    1. Re:Raw stats on movies... by vijayiyer · · Score: 1

      You forgot to multiply by the 24fps, even though you mentioned it. It's more like 24 MBps, or 200 Mbps before compression.

    2. Re:Raw stats on movies... by Anonymous Coward · · Score: 0

      720x480x3x24 = 1 Megabyte?

    3. Re:Raw stats on movies... by MP3Chuck · · Score: 1

      Yea DivX is good, but if people's requirements for online movie purchases are along the same lines of some slashdotter's requirements for music services, it's useless unless the service provides uncompressed HDTV video and Dolby 1000.1 audio.

    4. Re:Raw stats on movies... by Kjella · · Score: 1

      720*480*24 (bits)*24 fps) = 200Mbit/s, not 10Mbit. No, 10:1 is not good. 200:1 is good. That's about the compression ratio on 1CD rips, I believe.

      Kjella

      --
      Live today, because you never know what tomorrow brings
  5. Tesla predicted this already? by brxndxn · · Score: 3, Interesting

    Didn't Tesla predict infinite bandwidth in the wireless spectrum by combining frequencies in certain combinations? ..

    --
    --- We need more Ron Paul!
  6. hmm by Tumbleweed · · Score: 1

    Okay, but how does that work - is that 360Mbps per cell, or per connection per cell? Big difference there if it has to be split up for each user on a cell.

    Oh, and if you're gonna dream, forget about the laptop - watch the movie on some LCD glasses or something. :)

  7. Press Release by erick99 · · Score: 5, Interesting
    When you get to this paragraph . . .

    Certain statements in this release, other than statements of historical fact, may include forward-looking information that involves various risks and uncertainties. These may include, without limitation, statements based on current expectations involving a number of risks and uncertainties related to all aspects of the wireless communications industry.

    . . . you can be pretty confident that you are reading a press release. This was written by the company that owns the equipment used in the test. This is essentially an advertisement.

    --
    http://www.busyweather.com/
  8. Is that all? by mikeophile · · Score: 4, Funny

    That's a double sided DVD in 3 minutes.

    I'm sorry, but if the DVD takes longer to download than it takes the microwave to heat a HotPocket, I'm still going to be annoyed.

    1. Re:Is that all? by gonerill · · Score: 1

      I'm sorry, but if the DVD takes longer to download than it takes the microwave to heat a HotPocket, I'm still going to be annoyed.
      You could always buy a 250 watt microwave.

    2. Re:Is that all? by seringen · · Score: 1

      yeah, but you could immediately stream that DVD. Just try THAT with a hotpocket!

    3. Re:Is that all? by linzeal · · Score: 2, Funny

      Don't worry at a certain bandwidth you will be able to hold the burrito between your laptop and the general direction of the wi-fi tower and cook the burrito while you wait!

    4. Re:Is that all? by Anonymous Coward · · Score: 0

      If you can consume a DVD faster than a warm Hot Pocket, you ... uhhh, you can certainly digest quickly.

      Oh well. I forget my point; it had something to do with the fact that DVD's != HotPockets!!!

  9. When can we can a whiff of this speed in the US ? by vishmaster · · Score: 1

    SO why am I still paying $30 dollars for a lucky-if-I-can-get-300kbps-all-the-time-connection and calling it broadband ?

    --
    ..And the people bowed and prayed, To the neon gods they made.
  10. Raw Speed Doesn't Mean Much by femto · · Score: 4, Insightful
    It's the 'spectral efficiency' (the number of bits per second per unit of bandwidth) and the ability of the receiver to reject other users signals that is important.

    It is relatively easy to do 360Mbps given the whole radio spectrum to play with. It's a lot harder when it is necessary to coexist with all other users or a limited bandwidth is available.

    The article doesn't give such information so Siemen's acheivement may be impressive, or then again it may not.

  11. Maybe in Europe by Bruha · · Score: 2, Interesting

    It'll be harder to realize any type of high speed wireless that is affordable here in the US. We'll have to see what WiMax eventually does.

  12. Black and White by loid_void · · Score: 1

    So I'm gonna shoot all my Blockbusters in Black and White for an even faster download.

    --
    Anyone seen my jagged little pill?
    1. Re:Black and White by loid_void · · Score: 1

      I guess I should have phased that with a question mark.

      --
      Anyone seen my jagged little pill?
  13. Huh? by div_B · · Score: 3, Informative

    Didn't Tesla predict infinite bandwidth in the wireless spectrum by combining frequencies in certain combinations? ..

    Isn't the range of frequencies available for combination itself the bandwidth?
    Wider band of frequencies => sharper pulses can be formed by fourier synthesis => more 1s and 0s transmitted in a given time-frame?

    1. Re:Huh? by viva_fourier · · Score: 1

      That's pretty much right:
      A wide bandwidth translates to a narrow pulse in the time-domain.

      OFDM(orthogonal frequency division multiplexing) is a spread-spectrum technique meaning it spreads its energy(the data) out over a wide range of carrier frequencies -- the total power output required is actually less than by using a single carrier.

      --
      and now back to the fallout shelter...
    2. Re:Huh? by _defiant_ · · Score: 5, Informative
      OFDM(orthogonal frequency division multiplexing) is a spread-spectrum technique meaning it spreads its energy(the data) out over a wide range of carrier frequencies -- the total power output required is actually less than by using a single carrier.

      It's even smarter than that! Your little rect in time domain is an inf. sinc in the frequency domain. Of course, after a certain length it dies down to a negligible strength (call this point B). If you wanted to modulate another pulse, to guarantee they will both be exactly recoverable you need to modulate the new pulse up to 2B.

      OFDM basically take advantage of the fact that the signal is digital. Instead of modulating the next pulse at 2B, you modulate it so that the next pulse is centered over the first zero crossing of the first pulse. Normally, this would cause horrible aliasing, but since you know the shape of your input data, all you care about are the values at the origin and the zero crossing. You don't care about recovering the two original signals exactly, the value at the origin and the first zero crossing give you enough information to reconstruct them. Aliasing be damned!

      This takes advantage of the fact that simpler data is more resistant to noise. If you know what you're sending is a 1 or 0, then the waveform can be horribly degraded before it makes a difference. Contrast this with simple voice data, where a deformation in the wave can't be repaired (you don't know what it should look like). In this case, your encoding scheme introduces noise it knows doesn't matter in order to save bandwidth.

      Of course, this is also a form of quadrature multiplexing, which lets you send two signals at the same carrier frequency but differentiate them based on the phase. So that gives you twice the transfer amount you'd normally get above.

      (yes, I'm in a communications theory course right now)

  14. except for... by Anonymous Coward · · Score: 4, Funny

    > It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Well, except for the Americans, who will get it 15 years after everybody else does, but claim they invented it.

    1. Re:except for... by DriedClexler · · Score: 0

      Why didn't you make your post a reply in that thread instead of starting a new one?

      --
      Information theory is life. The rest is just the KL divergence.
    2. Re:except for... by rsidd · · Score: 1
      Why didn't you make your post a reply in that thread

      It was a reply: in case you didn't notice, the quote is from the main posting.

  15. Re:When can we can a whiff of this speed in the US by emmons · · Score: 2, Informative

    Because your cable company still has to pay off the bonds it issued in the 80s to put the cable in the ground in the first place.

    --
    Do you even know anything about perl? -- AC Replying to Tom Christiansen post.
  16. 360Mbps++ by Schwing84 · · Score: 0

    Now i can find a nice wireless hotspot and download faster then ever before. Who needs to pay to use dial up when wireless is faster and "free".

  17. Hmm, and this helps us how? by goneutt · · Score: 5, Interesting

    Since almost all servers are not connected to better than 100Mbps (I haven't been on that side of the eq since 1998 so I'm making assumptions, 'scuze me if I'm wrong) , network congestion, etc, I never see the full bandwidth of my 4Mbps line used on one task. 360Mbps might make for an impressive show of ability, but that has limitations at other bottle necks.

    The only immediate application I can think of for is setting up temporary offices where you don't want the expense of cabling, but even then you quickly fill the RF bandwidth.

    --
    Bacardi + slashdot = negative karma.
    1. Re:Hmm, and this helps us how? by Agilis · · Score: 1

      Although there's no practical value in having 1 of a group of bottlenecks relaxed, there's still value in relaxing it. Innovation in leaps or babysteps is innovation nonetheless.

    2. Re:Hmm, and this helps us how? by Kiryat+Malachi · · Score: 1

      Wireless is a shared medium, so that 360 Mbps is divided by the number of users. The point is that it becomes possible to support more users in a given amount of bandwidth at a reasonable speed, not that a single user could get a (generally unnecessary) higher max speed.

      --

      ---
      Mod me down, you fucking twits. Go ahead. I dare you.
      (I read with sigs off.)
  18. Okay, that's it! by Idou · · Score: 1

    I'm moving to Munich, Germany!

    --
    Sdelat' Ameriku velikoy Snova!
    1. Re:Okay, that's it! by dapyx · · Score: 0

      Also remember that Octoberfest is starting!

      --
      I'm sorry, the number you have dialed is an imaginary number. Please rotate your phone 90 degrees and dial again.
    2. Re:Okay, that's it! by Anonymous Coward · · Score: 0

      Actually, it's ending next weekend. But there will also be one next year...

    3. Re:Okay, that's it! by KontinMonet · · Score: 1

      But there's plenty of other beer fests such as Fasching, the StarkBeer (proper beer, unlike the crap served at the Oktoberfest) fest and so on...

      --
      Did he inhale?
    4. Re:Okay, that's it! by Anonymous Coward · · Score: 0
    5. Re:Okay, that's it! by Anonymous Coward · · Score: 0

      No, don't!

      Munich is in Bavaria, an ugly conservative shithole. Move to Berlin or Hamburg!

    6. Re:Okay, that's it! by Idou · · Score: 1

      If the local goverments of those cities switch to open source pased platforms, I will seriously consider . . .

      --
      Sdelat' Ameriku velikoy Snova!
  19. Why would you by clovis · · Score: 1

    "It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Why would you leave the house in the first place?

    1. Re:Why would you by m1chael · · Score: 0

      Why would you get wireless? Oh I know, actually, no I don't. You can have a wire to the can.

      --
      I know you are psychotic, but please make an effort.
  20. Comcast gives you 3MB/s for $40/month by Anonymous Coward · · Score: 0

    Welcome to 2002.

    1. Re:Comcast gives you 3MB/s for $40/month by Anonymous Coward · · Score: 0

      I pay that $40/mo and am lucky if I can get 300Kbps ...Welcome to Comcast service in the NW

  21. Reality Break by Anonymous Coward · · Score: 0

    "It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Actually, you'll be doing it in your flying car.

  22. Yes it can by Halvard · · Score: 2

    It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Especially in the US it can take quite a while to deplay. Since this likely will end up with service providers, you surely don't expect that they would offer the maximum bandwidth for short change do you? Likely, it would be metered or used for last mile, since interconnecting landline circuits would be a lot slower.

  23. No... by Conspiracy_Of_Doves · · Score: 1

    It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?

    Not those of us living in the US. Surely you don't expect this technology to come to America any time soon. We are always the last to get the really cool stuff.

    1. Re:No... by rooijan · · Score: 1

      Try living in Africa for a while (I'm in South Africa) and then talk about always being the last to get the really cool stuff.

      We only got ISDN a few years ago, and that isn't widely distibuted yet. Broadband, via ASDL and satellite linkage, is a distant dream for most people (heck, for most of our rural population, a telephone and electricity is a distant dream :( ).

      I agree, the US is probably less technologically favoured than Europe, but from our perspective, everyone else, North America, Europe, Australia, half of Asia etc, looks like high-tech demigods :)

      I'm not trying to start anything, nor am I saying you should just sit back and smile about what you have because you have more than us. I'm just pointing out how different parts of the world can have incredibly different perspectives of the same issue :)

      --
      Daar is nie 'n lepel nie
    2. Re:No... by povvell · · Score: 1

      Heh, not true actually, unless Raleigh has suddenly moved location to West Africa?

    3. Re:No... by k2r · · Score: 1

      Well, you can't have it all - at least you still get the coolest cluster bombs, assault guns and chemical weapons.

      k2r

      (some of my best friends are American :-)

  24. ofdm vs. cdma by Anonymous Coward · · Score: 0

    Anyone who knows care to explain the difference between OFDM and CDMA? They sound very similar to me.

    1. Re:ofdm vs. cdma by Wesley+Felter · · Score: 4, Informative

      OFDM is a modulation technique (i.e. it turns 1s and 0s into radio waves) and CMDA is a multiple-access technique (i.e. it lets multiple radios share a channel), so they're really orthogonal.

    2. Re:ofdm vs. cdma by ddent · · Score: 1

      If that pun was intentional, it was awful. In fact, even if it wasn't...

    3. Re:ofdm vs. cdma by femto · · Score: 2, Informative
      Actually, OFDM is a special case of CDMA.

      CDMA is simply a way of superimposing multiple data streams (users) which have been encoded in some way (typically by mutiplying by a code sequence). This is a very general technique. Choose the CDMA codes to be a set of orthogonal sine waves and the result is OFDM.

      Ultimately CDMA and OFDM have the same performance (they are the same thing) but the special case of OFDM is typically easier to implement. The symmetry of the OFDM code set allows an FFT to be used to separate data streams.

      A typical wireless LAN assigns all codes (carriers) to a single user but that doesn't have to be the case.

      As a further example, chose the codes to be a set of orthogoal pulses and CDMA becomes TDMA.

      CDMA is really just another name for 'superposition', that is, construction a linear combination of a set of sequences. The sequences don't even have to be orthogonal.

  25. Cisco did this 6-7 years ago by dangermen · · Score: 4, Informative

    I remember Cisco offering a product six or seven years ago that did vectored orthogonal frequency division multiplexing. It could do 45mbps non-line of sight as point-to-point or as a unidirectional 28 channel T1'looking setup al la Cisco 2600 WIC Cards. I wonder how this is different.

    1. Re:Cisco did this 6-7 years ago by Willis+Wasabi · · Score: 1

      Um, in that it's 8 times faster? And that Cisco seems to have ditched any wireless cards they had 6-7 years ago after the acquisition that gave them the Aironet cards?

      --
      All true wisdom can be found in sigs.
  26. Heute 360Mbs.... by Anonymous Coward · · Score: 3, Funny

    MORGEN DIE WELT!!!!!!!

    crowd rises in unison, tosses old telco equipment on raging fire...

  27. Not Max enough by Doc+Ruby · · Score: 4, Interesting

    "In the train" sounds good for 360Mbps, because each metal container will hold about 200 people max, which is at least about 1.8Mbps each. For Munich's 1.5M people, that's about 240bps, using a single hotspot. Such a system is better deployed by the city itself, for its mobile services. That doesn't feed bandwidth directly to the citizens, but rather to teams of people, like a fire engine with a WiFi gateway for WLAN.

    --

    --
    make install -not war

  28. Surely can't be long-P2P Hate crimes. by Anonymous Coward · · Score: 0

    "It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?""

    Gee I can't imagine why people see slashdotters as hypocrites? A new technology comes out and the FIRST thing we want to do with it is download movies. Can't you guys think of anything else that doesn't involve the supposed object of your hate?

  29. Re:How much "radio pollution" ...? By analogy ... by ankhank · · Score: 1

    Two authorities:
    1) Heinlein's "Waldo"
    2) What happens when many different frequencies exist in the same medium at the same time? You get localized extreme energy spikes. It took, oh, 200 years for this to be understood as actually happening on the ocean, although the math was clear that it would be expected.

    For ubiquitous wireless signals? Oh, probably no worse than upping the background level of energetic cosmic rays by a few orders of magnitude, and it wouldn't be provable harm so no economic cost involved to the industry should it happen.

    Same as with shipbuilding -- math said the waves would be there; but nobody on a really big ship ever came back reporting a really big wave, for many years, so they kept building them.

    (And losing them steadily ...)

    Worth considering.

    Viz: http://www.ifremer.fr/metocean/conferences/wk.htm

  30. No...We invented the inventor. by Anonymous Coward · · Score: 0

    "We are always the last to get the really cool stuff."

    We got Al Gore before everyone else.

  31. Re:How much "radio pollution" ...? By analogy ... by ankhank · · Score: 1

    And a bit more rigorously worked out here, for two slightly different waves interacting. Imagine more than two... http://www.ams.org/new-in-math/roguewaves.pdf/

  32. I doubt it.... by novalogic · · Score: 2, Insightful

    Doubtful, if the current trends in American markets keep up, it would be a decade easy before we get to this point. If you don't belive me, just look at this link it's more profitable for a company to offer slower service, not upgrade, and charge by the Kilobyte, rather then broadband us.

    --
    --
  33. cable sucks by Anonymous Coward · · Score: 0

    Thats faster then the speed on most American Cable Internet / DSL connections. America has horrible technology when it comes to internet connectivity. I want my European 100Mbps lan connection.

  34. Better colors by Anonymous Coward · · Score: 0
  35. I doubt it....Salad bar. by Anonymous Coward · · Score: 0

    Of course. Even the all-you-can-eat places are counting on their being limits. Whomever told the geek community that there are no limits lied to us.

    If geeks really want what they want? Then they're going to have to show the powers that be that it's in there own interest to give the geeks what they want.

    So far all that has been shown is how the technology can be abused, to the powers that be's detriment.

    "You scratch my back, I'll claw your eyes out."

  36. Re:How much "radio pollution" ...? By analogy ... by femto · · Score: 0, Offtopic

    Completely off the planet, but I wonder if the 'big bang' was just a rogue wave?

  37. Re:When can we can a whiff of this speed in the US by Chuqmystr · · Score: 1
    When you ask? WHEN?!? NEVER! That is unless you want to give your firstborn unto the infinitely evil wireless carier who's name should not be uttered *cough* verizon *cough* and agree to be indentured to them for a few hundred dollars a month for a few years.

    EVDO won't be the last big speed-hop from them for awhile. I'm pretty certain that within the next ~5 years they'll muscle LG and Moto into making handsets and NICs based on some new tech and declare CDMA 1X/EVDO dead. Then the 1 - 2 years of "conveinient customer upgrades" mayhem will ensue and even newer service plans with more loopholes and pratfalls that the U.S. taxcodes will also ensue. I work for them and have seen it all before.

    One thing is for certain. "Cellular" as we know it will go away soon and both voice and all other datas will become one, at least from the technical overview. Actually, that's already happened from the network standpoint in some cases. Look at the VOIP techs used for PTT (annoying walkie-talkie like services like Nextel) by Sprint, VZW and soon Cingular/Tmo. However, as long as a distinction between voice usage and other data services can be made in the Joe Common Customer mind then there will be endless, confusing and overpriced plans to give these things to the customer. Nevermind the little man behind the curtain, just worship and obey the great wizard!

    Something else to mention on that note, as sysadminery becomes more advanced (well, when they start to get a clue...) these wireless cariers will be better suited to restricting unpaid services. Gone will be the days of unlimited 1x (and soon EVDO data) on Sprint's network by signing up for a particular plan and purchasing a $20 data cable.

    My apology for getting a bit off-topic there but that is my forecast of high-speed wireless data in the U.S. based on current business practices. The wireless cariers have found their new cash cow and it involves we customers chasing a carrot on a stick. It's far too late to vote with our feet IMHO. That is unless Tmobile keeps up their great service. But that's just how I see things.

  38. OFDM is old technology by Bored+Huge+Krill · · Score: 3, Informative

    This article seems to imply that OFDM (used in 802.11a and 802.11g) is somehow a "new" technology. It isn't. It turns out to be quite hard to find the oldest use of OFDM, because it appears to have been used in military systems which were classified long before it became publicly known. However, the oldest published document I know of is a patent for orthogonal frequency multiplexing, filed in 1966 (granted in 1970) by Robert W. Chang of Bell Labs. I don't remember the patent number off the top of my head. :-) The real change to get enormous data rate with increased spectral efficiency (which you'll really need...) over a useful range is MIMO (multiple input multiple output) which uses spatial diversity to effectively create many spatially diverse (mostly) independent communication channels simultaneously on the same frequency channel. Methods combining OFDM and MIMO make up all of the front running proposals for the future 802.11n standard currently in the works.

    1. Re:OFDM is old technology by pe1chl · · Score: 1

      OFDM may not be new as a technology, but what is "new" is the possibility of implementing it in consumer-grade devices, made possible by the more and more powerful and ever cheaper DSP devices.
      Of course not "new" in the sense that it should appear in a news article today, but practical use of OFDM at megabit rates has only been possible for a couple of years.

  39. radio pollution and the shannon limit by j1m+5n0w · · Score: 4, Informative

    Well, Claude Shannon showed that, with a perfect modulation and error correction scheme, you could only push so much data over a given communications media, with a given amount of bandwidth and SNR. If you want more, you have to either

    • use more spectrum (aka bandwidth)
    • increase signal strength
    • decrease noise

    Since background noise is not controllable, they would have to be doing one of the first two (effectively increasing radio pollution), or overcoming inefficiencies in a previous modulation scheme.

    Anyone know how close the various 802.11 standards are to the shannon limit?

    -jim

    1. Re:radio pollution and the shannon limit by div_2n · · Score: 4, Insightful

      Increasing signal cannot and would not provide you with more bandwidth. It might help you overcome noise thus maximizing your current maximum capacity. But increasing signal also increases the possiblity of reflections which in turn increases noise.

      The best possibility is to use the maximum signal strength required to be "heard" over the noise which, given the possibility of reflections, it is sometimes actually less and not more.

      All things being equal, the only real way to increase bandwidth is to increase the amount of spectrum you use. But not all modulation is created equal as is shown in 802.11g (ODFM) vs. 802.11b (DSSS). Same spectrum, different results. Wimax is one attempt to not only increase the amount of spectrum used, but increase the effeciency of the modulation technique to make the most of the bandwidth in that spectrum.

      That and it also happens to be a theoretical competitor to telcos (cellular included) because of the possibilities it might offer.

    2. Re:radio pollution and the shannon limit by Anonymous Coward · · Score: 1, Informative

      Well, the shannon limit only aplies to single input single output (SISO) channels. Future high data rate wireless systems will use multiple input multiple output (MIMO) which exploits multipath channels. Using multiple transmit and receive antennas you can increase data rates without using any more spectrum. I think you can effectively get *N speed up where N is the number of transmit or receive antennas. It works because the channels created by separating the antennas in space by a certain multiple of wavelengths are uncorrelated. Through special coding techniques you can use these like they are separate channels but still use the same frequency bandwidth.

      Here's a cool link: http://www.linuxjournal.com/article.php?sid=7386

      which talks about how a research group at a company in New Zealand is using Linux to help in development of space-time systems. I think the future 802.11n standard will use MIMO to get the high data rates people desire, without increase spectrum usage.

    3. Re:radio pollution and the shannon limit by Cprossu · · Score: 1


      thanks for the extra info-it is very much appreciated...

      it would also be interesting to get this into the sub atomic field and seeing how certain close bandwidths of photons (as radio waves arn't really waves for se) actually will interact with eachother.

      one wonders how it would screw with theese types of multiple transmissions to have very precise surfaces in which one spectrum of photon would go through, yet one with a spectrum just above it would----
      ok im going off into theoretical (and probably absolutly wrong territory, sorry)

      ok getting back to the subject of wireless tech..
      how much bandwidth do you think we could possibly have in wireless if we A) figured out how to actually accuratly detect neutrinos B) built miniture accelerators (and detectors) which would send neutrinos in some sort of pattern(and recieve respectivly) from some controlled element reaction
      ok mabye all i needed to ask is how much data is it possible to send if we utilize neutrinos which are less likely to interact with anything know today instead of photons(radio)

      i better end this now-im sorry lol

    4. Re:radio pollution and the shannon limit by femto · · Score: 2, Informative
      You've missed out an option:
      • Increase spatial diversity

      This is the spatial equivalent to the time/frequency option of 'use more spectrum'. Achieving spatial diversity is typically done by adding more antennas (and RF gear) to the receiver and transmitter.

      As an example, a special (simple) case of spatial diversity is using an array of antennas to do beamforming. Making the antenna occupy more space increases the antenna gain (directivity) allowing multiple data streams to reuse the same frequency.

      In its most general form, spatial diversity allows multiple streams of data to be transmitted and received on the same antenna array, thus allowing capacity to be boosted over what you would expect from the wikipedia version of Shannon's equation.

      In actual fact, the 'W' in wikipedia's equation should be a matrix involving spatial terms. This fact was discovered a decade or two ago and forms the basis of the hot topic of MIMO or space-time coding. An update to the 802.X standard, based on these techniques, is in the pipeline.

      It's an ongoing topic of research to discover what the 'real' Shannon limit is when spatial diversity is taken into account. It looks (by my understanding) to be a function of the available frequency bandwidth and the available volume of space measured in wavelengths.

    5. Re:radio pollution and the shannon limit by Anonymous Coward · · Score: 1, Informative

      Increasing signal cannot and would not provide you with more bandwidth. It might help you overcome noise thus maximizing your current maximum capacity. But increasing signal also increases the possiblity of reflections which in turn increases noise.

      Wrong. The most effective modulation you can use depends on the SNR. With a given noise level, increasing the signal power allows using a more efficient modulation scheme (packing more bits per baud). The more bits per baud, the highest the SNR required.
      This is of course a simplification. As other said increasing power is not a magic solution. But is usually helps.

    6. Re:radio pollution and the shannon limit by jsebrech · · Score: 1

      If you want more, you have to either

      * use more spectrum (aka bandwidth)
      * increase signal strength
      * decrease noise


      But you can use more spectrum while still using the same range of frequencies, by finding a way around interference of signals at frequencies close to eachother. From the blurb about OFDM it seems that's what they're doing. Combining different signals at frequencies very close to eachother in such a way that they interfere in the air, but can be picked apart again at the receiver due to the specific waveform and timing they use.

    7. Re:radio pollution and the shannon limit by Jott42 · · Score: 1

      This is not correct. Increasing the power increases the SNR, and increases the maximimum possible bandwidth.

      Exhibit 1: Shannons law Exhibit 2: Various coding schemes actually make use of the reflections, which therefore is not a problem anymore. One extreme version of this is MIMO systems.

    8. Re:radio pollution and the shannon limit by Czernobog · · Score: 1

      There is no "real" or "fake" Shannon limit.
      The Shannon limit is the same regardless if you use multiplexed data at the source, or a complex propagation model.
      In short, no form of source or channel coding (such as MIMO) alters the limit of the capacity of the channel.

      As far as MIMO matrices go, the elements of the matrix represent the configuration of Tx antennas (coefficients representing the source signal) in relation to the the number of channels (coefficients that represent the radio channel envelope) are used to propagate the information.

      --
      /. Where the truth
    9. Re:radio pollution and the shannon limit by sploxx · · Score: 2, Informative

      OMG. +5 Insightful. I have to do something about it.

      Increasing signal cannot and would not provide you with more bandwidth. It might help you overcome noise thus maximizing your current maximum capacity. But increasing signal also increases the possiblity of reflections which in turn increases noise.

      No. And yes for the last part. But this is not the whole truth.

      Did you know that Maxwell's equations were *linear*? I.e. if you increase the output power by a certain factor, you increase the received power by the same factor if all else parameters (location etc.) are constant. Interference patterns (your described noise) don't change their form. The signal increases and also the amount of noise *caused by scattering*. All else noise powers stay the same (noise in the receiver electronics, noise from electric switches/lightnings etc). So the overall SNR gets better -> the datarate gets better.
      Of course, there are limiting factors. I.e. too strong sources may overshine weaker ones in a WLAN setting our you may just see all the nodes of every WLAN in a city (thereby decreasing bandwidth). There's an optimum. Directional antennas help in this case.

      Or do you want to say that you have to take non-linearity in vacuum or materials (i.e. air/concrete) into the equation? Hello?! We're not talking about 511keV photons creating electrons/positrons or polarising frequency multiplier crystals with lasers or similar stuff.

    10. Re:radio pollution and the shannon limit by Anonymous Coward · · Score: 0
      Doesn't it depend on how one defines channel?

      If the channel is defined to be between two NxN antenna arrays, the capacity is ideally N times the single antenna case.

      If the channel is defined per antenna, it can be said that the channel capacity is constant but the number of channels is increasing, so in the NxN case we have N parallel channels.

      Either way the the maths is the same.

    11. Re:radio pollution and the shannon limit by Czernobog · · Score: 1

      Capacity is defined per channel. So when you have a SIMO, MISO, MIMO, SISO configuration, you have M, M, MxM and 1 respectively channels.
      The bonus schemes like these give, is that while individual channels are not very good (in comparison to the theoretical of Shannon's maximum) when multiplexed in configurations like that, the total capacity of the system and not of the channel is a lot closer to Shannon's curve for a channel with the equivalent total capacity.

      --
      /. Where the truth
    12. Re:radio pollution and the shannon limit by femto · · Score: 1
      Hmmm. I don't agree with you here.

      What you say is true in the absence of mutipath propagation (without independent fading). It is not true for an independently fading channel. Using MIMO on an independently fading channel (ie. multiplicative noise) does allow capacity to exceed what is possible in a SISO system operating at the Shannon limit.

      I refer to to Foschini's seminal paper on the subject.

      This web page sums it up:

      MIMO systems retain all the properties of SIMO/MISO systems, since in some sense the optimization of the transmitting and receiving antenna elements is carried out in a superset of that of SIMO/MISO. In reality, MIMO systems offers advantages which go far beyond that of conventional smart antennas, as was first hinted in a breakthrough paper by J. Foschnini at Lucent Tech. in 1996 [Foschini96]. In this paper, Foschini shows that if the NxM channel matrix describing the wireless link in a M-transmit N-receive system has ideal independently fading elements, then the capacity of such a system grows linearly with the smallest number of antennas min(N,M) and no longer with the log function. An incredible improvement over the more traditional SIMO/MISO case. A similar result was also reported in [Telatar95]. In parallel, Foschini also developed a practical transmitter/receiver algorithm to beused in the MIMO context: the now famous "BLAST" algorithm [Foschini96]. Later another breakthrough scheme was proposed by ATT-Labs based on the idea of space-time coding [Tarokh98] to extract diversity gains in MISOthen MIMO.

      I'm interested in any objections you still have, just in case there is a shortcoming in my knowledge.

    13. Re:radio pollution and the shannon limit by Czernobog · · Score: 1

      Fair enough. Foschini's paper had slipped past me.

      --
      /. Where the truth
  40. Give me liberty, or give me static. by Anonymous Coward · · Score: 0

    "Since background noise is not controllable"

    Controllable no. Maybe biology has the answer though. Especially when you consider communications that use ultralow everything.

    Chaos theory could help in using noise instead of fighting it.

  41. Perhaps a bit off-topic... by chrisbro · · Score: 0, Redundant

    ...but how is power consumption looking for long-range wireless transmissions on the user end? Is it going to drain laptop batteries in a heartbeat? I know there'a a large power difference between Bluetooth and Wifi, how big is the jump to the new long-range wireless plans?

  42. Re:Nice troll by B2382F29 · · Score: 2, Informative

    You had neither the first satellite in orbit nor the first man in space, nor did you create the first modern rocket.

    You did not discover Fission neither did you understand the theory behind it.

    Oh, and you didn't invent computers.

    Now, you sure are proud of being the first nation creating the Nuclear Bomb and USING it.

    --
    Move Sig. For great justice.
  43. Ortho what? by ryanjensen · · Score: 1

    Did anyone else read that as "ornithological frequency division multiplexing (OFDM)" at first, or is it just me?

  44. OFDM is already used for high bandwidth streaming! by Goth+Biker+Babe · · Score: 2, Informative

    Last night, as I sat in bed, I channel hopped and ended up watching BBC 3 on my bedroom TV which receives it's signal through a small set top antenna. In fact that TV can pick up over seventy TV and Radio channels through that antenna.

    Why? Because DVB-T, the terrestrial form of the DVB digital television standard uses OFDM to ensure signal reliability. There are roughly eight TV channels per multiplex at PAL resolution which is quite a bandwidth. So how is this new?

  45. But not in a german train by Down_in_the_Park · · Score: 1

    "It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?" If you have ever used a german train you wouldn't have made this comment. Although there are relieable and fast, a mobile connection is the last thing you can hope for. It feels a bit like no longer being in germany once you entered a train. So no matter what connection speed, expect gaps from 5 sec to 15 min in your movie... wait than a David Hasselhoff movie can even be fun...

    --
    "People who are willing to sacrifice essential freedoms for security deserve neither freedom nor security."

    B F
    1. Re:But not in a german train by BarryNorton · · Score: 1

      Yeah, but at least you get somewhere to plug in your laptop! (Credit to Virgin for finally bringing this much-needed feature to the British rail network... by buying German trains!)

    2. Re:But not in a german train by Down_in_the_Park · · Score: 1

      Oh well, at least you have some plugs (4 per waggon), which helps at least. But if you consider that Siemens is also building the trains, you wonder why they can't manage to estabish a repeater or a amplifier in the trains, particular the new ICE are really bad if it come to a mobile connections.

      --
      "People who are willing to sacrifice essential freedoms for security deserve neither freedom nor security."

      B F
    3. Re:But not in a german train by BarryNorton · · Score: 1

      It's true, they should. (But this will never happen on the British rail network... on the London Underground, yes it's planned, but otherwise...)

      As it goes Virgin (in the UK) are doing something for data (given that they operate long connections between hi-tech destinations, connecting, for instance, Yorkshire with Newcastle, Edinburgh and Southampton) with wireless on board... sadly only in first class - academics aren't allowed to travel first class :(

    4. Re:But not in a german train by ahillen · · Score: 1

      Oh well, at least you have some plugs (4 per waggon), which helps at least. But if you consider that Siemens is also building the trains, you wonder why they can't manage to estabish a repeater or a amplifier in the trains, particular the new ICE are really bad if it come to a mobile connections.

      Actually they do manage. The new (=since 2000) ICE3 trains actually have repeaters in some sections of the trains (and sockets at every seat pair). That they don't have repeaters everywhere is more due to what Deutsche Bahn wants and less due to what Siemens could do.

    5. Re:But not in a german train by BarryNorton · · Score: 1

      Yeah, I thought the newer ICE trains I've used in Bavaria (including last week) were like the ones Virgin bought with a socket at every seat...

  46. the story by nilbog · · Score: 1

    the story never changes, only the numbers. Actually, the number don't even change, just the units of measurement.

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    or else!
  47. Re:When can we can a whiff of this speed in the US by Anonymous Coward · · Score: 0

    Okay, you're still off with 300kbps?
    Here, where you can dl a DVD within ~3mins while filling up your car and pay or waiting for the bus, the standart is abouts 768kbps and will soon be upgraded - by most companies think - to a full 1024kbps...

  48. Give me my cheap mobile net damnit! by t_allardyce · · Score: 1

    Mobile net is all very good, but will this actually be affordable by the average person? Most households are fine with paying a monthly fee in the region of around 10 - 25 quid for either unlimited adsl or old dial-up but mobile phone companies seem to think that they have to rip us off or else they don't get to eat! GPRS is still charged in cave-man prices, If anyone is prepaired to offer a proper mobile internet service, flat-rate at the same monthly fee as adsl then i reckon most people would drop their home connections and switch to this - even if it was only 256k/s!

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    This comment does not represent the views or opinions of the user.
    1. Re:Give me my cheap mobile net damnit! by Anonymous Coward · · Score: 0

      The reason providers charge so much is because the bandwidth available for GPRS is very limited. They couldn't offer flat rate 256K/s services, the service would get hammered into oblivion and it would be mercilessly slow for everyone.

  49. Fastest DSL? by Anonymous Coward · · Score: 0

    Erm. The press release claims that 360 Mbps is "around one hundred times faster than the fastest DSL connection available today." In Sweden you can get 8 Mbps ADSL connections, and 26 Mbps VDSL. Or is there some sort of special maths going on here that I'm missing?

  50. Don't make a joke with him!!! by c0p0n · · Score: 1

    I still feel scared by Kat and its two-way movement front leds...

    --

    Your head a splode
    1. Re:Don't make a joke with him!!! by Anonymous Coward · · Score: 0

      That would be KITT (Knight Industries Two Thousand), you ninny.

    2. Re:Don't make a joke with him!!! by c0p0n · · Score: 1

      Nope, KITT was Michael Knight's car. KAT (not sure of how it should be written, but the "a" sounds like "u" in "cup", at least the translation to spanish) was an EVIL KITT, made by some villain else.

      --

      Your head a splode
  51. Re:Why do I stil pay $30/mo by Anonymous Coward · · Score: 0

    Maybe because you live in the US where the telecommunications companies maintain an imposing presence in Washington DC.

  52. Re:MIMO Systems by 183771 · · Score: 1

    MIMO Systems == Multiple Input Multiple Output Systems

    http://www.signal.uu.se/Research/rdiversity.html

  53. Yeah, but what's the range??? by darkonc · · Score: 1
    "I've got 500Megabit wireless on my laptop!"
    "So then why are you carrying around that long ethernet cable?"
    "It doesn't go to the laptop, it goes to the transmitter -- It's only got a 6 inch range.

    (something like that actually happened at one computer lab where I worked.. They tried getting a cordless phone to use in the lab, but all of the computers generated so much interference that it only had a 3 foot range, so we ended upsing a regular phone with a 40 foot extension cord)

    In this case, I realize it's probably better than that, but it twigged a memory.

    --
    Sometimes boldness is in fashion. Sometimes only the brave will be bold.
  54. been there done that by Anonymous Coward · · Score: 0

    Orange in the UK did this ages ago. Admittedly it took 36,000 phones connected in parallel, but hey our GPRS system is up there with the rest of the world guys.

  55. Tesla? WTF?! by Anonymous Coward · · Score: 0

    I thought these guys were all out of work. I guess like everyone else, they turned to IT for an alternate career.
    http://www.teslatheband.com/home.aspx

  56. Re:OFDM is already used for high bandwidth streami by Binestar · · Score: 1

    There are roughly eight TV channels per multiplex at PAL resolution which is quite a bandwidth. So how is this new?

    Does your TV Stream 8 TV channels back to the stations?

    --
    Do you Gentoo!?