Homemade VoIP Network Over Wi-Fi Routers

AnInkle writes "A blogger on The Tech Report details his research and testing of wireless voice communication options for remote mountainous villages in rural undeveloped areas. The home-built project involves open-source software, low-cost wireless routers, solar power, mesh networking, unlicensed radio frequencies and VoIP technology. Although his research began several months ago, he has concluded the first stage of testing and is preparing to move near one of the sites where he hopes to eventually install the final functional network. Anyone with experience or ideas on the subject is invited to offer input and advice."

Re:Why not cellular?

[Timberwolf0122]

I think the main drive according to the article is the 802.11x frequencies tend to be de-regulated and free to use, cell networks have ongoing fees to use that portion of the spectrum. Also wireless routers have very low power requirements and can be run via hippy fuel (aka solar) instead of some poor bugger having to run the mother of all extension cords up a mountain.

Re:Urban Networks...

[Opportunist]

Zero chance. I'd even deem it unlikely that the original project survives for long. Telcos are missing out revenue when you communicate for free, the feds owe them one for the wiretapping thing, so I expect a law soon against this. Because of ... because of ... national security or whatever fits.

Tried something similar... didn't work well

[cciRRus]

I experimented with 5 units of WRT54G wireless routers running Freifunk firmware [freifunk.net] and I tried saturating the link with several G.729 VoIP calls. The system doesn't scale well. Over 3 hops, the number of calls greatly reduces as there is just too much random delay. In order for voice communication to be worthwhile, the latency cannot be more than 200ms although there are good forward error correction schemes and huge buffers.

Latency is a real problem especially when you are doing it over several hops. The "lag" isn't consistent. It will hit you at random interval, and that can be extremely irritating. This may be due to the use of CSMA/CA and RTS/CTS (depending on configuration). I haven't found a way to improve it though...

Re:Urban Networks...

[jamesh]

There are (still?) cell phones with DECT (household grade cordless phone technology) built in. I always thought this would be a much better alternative to a cell phone with wifi built in to accomplish VoIP. DECT is pretty lightweight, so do VoIP to the DECT base station, then DECT to the phone. When you are in range of the DECT base station (eg at your house) you'd make calls via that instead of the more expensive cell network.

Not sure why this never took off... could have something to do with the less money that the cell providers would make.

Re:Urban Networks...

[jimthehorsegod]

BT tried something not a million miles from this in the UK. Went by the name of BT Fusion and the principle was that the compatible handsets used Bluetooth to communicate with a base station (which was also a DSL Router) and thus your mobile/cell phone used that to route calls when in range. AFAIK the base station used normal PSTN lines to route the calls out, but that's just a technicality - it could have been doing whatever at that point, it would be transparent to the end user

overhead

[sgt scrub]

This brings me to a thought I have every time someone wants to know if they have enough bandwidth for voip. How much of h323, voip, etc.. is consumed to keep the whole accounting; pay per call, distance of call, who is calling, etc.. type stuff together? It seems to me a constant open stream where audio could traverse in any direction and any distance would not be that bandwidth intensive. Maybe I just don't understand everything involved.