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VoIP As a Solution To Rural Broadband
boyko.at.netqos recommends his article up at Network Performance Daily, which notes the recent reports that up to 30% of households do not have a landline telephone, preferring a VoIP or cell-phone based solution. What to do with the miles of last-mile phone line infrastructure already in place in almost all the homes across the country? Maybe there's a solution to rural broadband by using the high-reliability frequencies reserved for voice purely for data — and using VoIP to make phone calls. From the article: "Repurposing the broadband of 0-25kHz would result in... speeds of around 14.4 kBytes/s (or 115.9 kbits/s) upload and 28.8 kBytes/s (231.3 kbits/s) download. That's not much of a speed boost. Still, if you've been plodding along on a '56.6k' modem, at speeds of 7.2kBytes/s, this would be like an oasis in the desert. And what about those phone calls? Well, if you make the same phone calls with VoIP that you were with the standard 0-4kHz landline, it would only take about 20.8kbits/s using the G.723.1 codec — that still leaves you with 80% of your broadband capacity when on the phone — and 100% of your broadband when you're off it." Only the US FCC calls 231K "broadband," but as noted it does beat dialup.
Not to be pedantic (and I understand the general drift of the article), but from wikipedia: "... the US FCC used 200 kbit/s in their definition until march 19th 2008 after which it was scaled up to require a minimum of 768 kbit/s to be defined as broadband and at that time the FCC introduced new tiers in their definition as follows: 1) 200kbit/s to 768kbit/s ("first generation data"); 2) 768kbit/s to 1.5Mbit/s ("basic broadband"); 3) 1.5Mbit/s to 3 Mbit/s; 4) 3Mbit/s to 6 Mbit/s; and 5) 6Mbit/s and above." http://en.wikipedia.org/wiki/Broadband_Internet_access
And better than satellite since it shouldn't degrade when the weather isn't perfect. That was the main complaint of people I know who live in the boonies and have to go with satellite (note that those people don't require low latency).
Absolute power corrupts absolutely. indymedia
That was much like the overall premise and promise of ISDN BRI - "high speed" digital access over voice grade plant, which failed miserably due to a number of technical, political, and corporate reasons.
Granted, the OP's proposal is somewhat different, as I assume he was referring to using DSL-like technology in the full voice band. But, there are also limitations on how much data can be carried in a given amount of spectrum using various modulation and encoding schemes.
Seems silly to spend all that time and money trying to get the FCC to change its regulations when this situation seems tailor made for a good RFC 1149 implementation. Latency is still an issue with such a setup, but bandwidth can be virtually unlimited if you have the resources.
Sounds nice but,try to get the telco's to implement it in areas that they deem unprofitable without an act of congress. The best solution for broadband in the boonies as I see it would be broadband over powerlines.
It actually sounds like a good idea. Sure, it's not as fast as broadband, but it's still a good five times faster than dialup. And ten times faster than a lot of people get in those rural areas where no wired broadband is available.
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911 with VoiP?
And before someone says it - a lot of rural people don't depend on 911 anyway, I know (because of distance), but a lot of people us city folk would consider "rural" DO depend on 911.
And how do you IMPLEMENT this?
get every phone line set up for VoiP and train people, and then flick a switch one day? Do you stagger it so you move a chunk of people over to data, cap their speeds, and then move some more people? There WILL be holdouts - medical equipment, old credit card / check readers should work, but they'll have to be tested.
You won't be able to utilize the full bandwidth of that frequency range until you get everyone switched over. And who pays for it? Do you force this on everyone? A lot of people have no internet, and a lot pay through the nose (and have contracts) for satellite net service.
If we have money to be running around the countryside handing out VoiP phones, informing people, etc, why not just run some fiber all over hell? Let companies buy the last mile.
The major cost in both scenarios is paying for the man hours involved. We don't have the money for either plan (running fiber or getting people VoiP ready).
This is what ISDN is good for. It's not very demanding of loop quality, and you get uncompressed digital voice, plus modest data capability.
ISDN voice handsets are common in Europe. The Swiss PTT likes them. European practice is to power them from the central office, so you don't need power at the subscriber end. US practice is to power ISDN gear from the subscriber end, which makes them unreliable as a primary phone connection. There's no fundamental reason, though, why central office power for ISDN can't be used in the US. The gear is available.
The problem is that many rural lines have analog repeaters out on poles somewhere, and those are't compatible with DSL, ISDN, or much of anything else. See Rural Telephony Workshop Report..
This sounds pretty much like IDSL. The problem has never been technological - the problem is getting your telephone company to implement it at a price that's reasonable. Instead of breaking up the low frequencies into two 64 Kbit/sec ISDN BRI channels and one 16 Kbits/sec D channel for signaling, IDSL just uses all 144 Kbits/sec (symmetric) for data. The suggestion is asymmetric ISDN based broadband, but that's a minor difference. ISDN goes much longer distances than ADSL or SDSL due to the lower frequencies. In the early 1990s I had ISDN and it worked fine, except the phone company charged $ 250 a month for unlimited 128 Kbits/sec. Great technology (at the time), but insane pricing.
It's going to be Voice over IP over Voice? VoIPoV?
I'm not sure about the math, but when I was working on my Master's degree, an old tech from Bell labs told us that the reason DSL can't go very far is that load coils are placed in the copper lines to prevent capacitance over long distances. These coils also had the effect of wiping out everything but ~300 - ~3300 Hz. DSL's range is limited because the frequencies it uses can't reach past these load coils. Once that distance is reached, the only thing left is the 3-4 kHz that is required for a single voice call.
Hell is other people's code.
It gets 144kbps - ISDN has two 64kbps B channels and a 16kbps D channel, and is typically used for a 128kbps bonded circuit.
The big advantage of IDSL is distance - it typically gets about 30,000 feet, compared to about 18000 for most DSL flavors.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
There isn't too much information in the article, particularly what problems may be encountered. The amount of data that can be delivered will vary greatly due to certain technical considerations. Politically, giving everyone in rural areas the 'same lousy service' is a minefield.
The outside cable plant and distance to the central office is everything:
* "Wires on poles" can degrade bandwidth 10x or more, particularly if there is industrial or broadcast interference. Modern underground cable plant can provide several Mbit/s up to 30km or so.
* Loading coils, commonly used in the past to maintain 600 or 900 ohm line impedance, limit the bandwidth of the lines to not mush more than 4kHz. They must be removed which is allot of tedious labour. Once removed, POTS may not work properly. Since some lines will need them and others definitely not, this gives a great excuse to 'take forever' to install the service.
* COTS DSL-modem/routers, common in many areas, may not work on large runs. Slightly modified units can put out greater signal and have better echo cancellation. This looks like a lock-in and higher prices. Higher transmission levels, lower received levels and longer runs invite crosstalk in a big way. It may be that many systems start out really good, but quickly degrade as more subscribers are added.
* Some rural cable-plant is "hollow-sounding" with voice and will simply not work with DSL. I'm no expert on US rural phone systems, but its fair to say most will get the pitiful 256kbit/s rate. This is what can be achieved with above-ground cable-plant at 30km in a city environment. The actual case I use example is Buenos Aries.
Any cable-plant that doesn't support 25kHz should be recycled! Otherwise, most will probably do much better, so limiting service to below 256kbit/s is deceptive. All told, there are a number of technical hurdles, which can be overcome, but the politics will go on forever.
This isn't a nice comparison to make, but in England there is more 'broadband' (there is a somewhat higher standard to the definition there) in the country than the city. Of course, like most of Europe, all wires are underground.
Until recently moving off to college, I have lived in a rural area. For the four years of living in this area, I used ISDN for data only, while also having two separate landlines for voice-only use. Let me tell you, for the price of the line installation, monthly line fees, monthly per-dial fees, and shoddy service with a very low cap, ISDN is not worth it. It exceeded $100 per month. I've just recently switched to Sprint EVDO for data service, and the quality is amazing. In spite of having virtually nil DSL penetration and absolutely no cable, this area has full cellular coverage, and I get fairly decent speeds around 1mbit, which is a godsend compared to 112kbps. I think cellular networks should be the platform on which to deploy more rural services, while deep penetrating but expensive, antiquated services such as ISDN and T1 should be put to rest.
Power goes out. Landlines still work. Weather gets crappy. Landlines still work. Not much that can fail on the user's end. Start tossing VoIP in the picture and you're adding a whole bunch of equipment that has lot of ways to fail.