jfalcon

Voice/Data over 802.11

13 posts in this topic

So you have wifi cards and AP's. Has anyone tried to do voice/data with them? Like using it like a 2-way radio, broadcaster/CB or TNC?

[ed: clarification]

For instance, you have a AP at your house that you and your neighbors share/tie into/network. You want to talk to your neighbor like a radio without going through the muck of Instant Messengers.

Or, you have an AP in your car, you want to talk to another car or share info with them. Let's say you have a full blown Car PC while they have a Pocket PC. You want to use it like a radio and talk to them, simulcast/broadcast music to them, etc...

Is there an application like this? It wouldn't need TCP/IP but just a simple transport/data layer over the wireless Ethernet would suffice.

Basically it means turning the Access Points/Wifi cards into nothing more than data radios and get rid of alot of the crap that is heaped on. Probably can go with a common public SSID or some hardware MAC filtering for security purposes. But I haven't seen anything written that does this. I envision it with some sort of simple identifying/addressing (like mac addressing/ax.25 ID) but without the need for DHCP which would be unnecessary or subnet routing (think THENET/NETROM based routing) where nodes are sharing their "heard" stations and routing tables with better quality/less latency are dynamically created all the time and transmitted in the blind to others.

A real world application of this? Let's say you're in traffic. You see a hot babe in a car next to you (provided this network/equipment is well established in cars). You dial her license plate and "call her" via text/voice/video. She of course would have some kind of filtering. But let's say you show her your stored picture of your johnson. She: a.) smiles because it will be identified with your license plate or b.) flips you off in disgust and takes the next exit.

Another more "realistic" application would be again being stuck in traffic, you dial into a "public channel" (Braker, Braker, Braker 19) and listen to the chatter of what the hold up is. Most traffic slowdowns aren't because of the "accident" itself... it's because of the rubberneckers who want to see the carnage. Having something like this where people are sharing the "oh, it's just a fender bender... some glass... no body bags, etc.." info and having it where anyone can pipe in and give their two cents worth would be tight... not to mention maybe help flow go faster through this.

Or caravans with your friends sharing maps, music, chat, video, etc.. between cars. A framework for a APRS like network when your car is yanked (i'd probably still have backup transmitters and stuff too). Being able to rig an entire neighborhood with cameras that anyone living there can watch without issue for security (and scandal... isn't that the milk man? and why is she in her robe at 1pm? Not to mention people not unlike us trying to steal car stereos, tires, etc..) You know the rest. All without relying on a ISP connection (per-se).

In a way I guess it would be like bluejacking, but intentional over wifi which is alot more common place, faster and has better range.

Edited by jfalcon
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i got this cool thing that i use to talk to people......wait for it.......................................... cell phone.

Leave the helmet on, kid. We wouldn't want you to hurt yourself thinking being all special(-ed).

Did you think of this answer all by yourself?

Edited by jfalcon
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I don't know if the scenario you propose would be possible. I suppose you could set up an AD-HOC mesh network and then you some sort of LAN messaging application to communicate with people on the network. But, one of the problems would be the limited distance that Wifi can travel; since it it running at 2.4GHZ while CB radio is typically around 26.965 MHz-27.405 MHz you won be able to transmit nearly as far as a CB radio could.

All things consider I do think that your idea is very interesting.

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I don't know if the scenario you propose would be possible. I suppose you could set up an AD-HOC mesh network and then you some sort of LAN messaging application to communicate with people on the network. But, one of the problems would be the limited distance that Wifi can travel; since it it running at 2.4GHZ while CB radio is typically around 26.965 MHz-27.405 MHz you won be able to transmit nearly as far as a CB radio could.

All things consider I do think that your idea is very interesting.

Just use this (WL-2400 50 50 Watt Wireless LAN Amplifier) if distance is an issue.

Edit: I guess the easiest way to do it would be to set up your laptop/car PC as an AP and have people redirected to a splash screen that tells them how to connect to Asterisk running on the same laptop/ car PC with a softphone.

Edited by m3747r0n
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I don't know if the scenario you propose would be possible. I suppose you could set up an AD-HOC mesh network and then you some sort of LAN messaging application to communicate with people on the network. But, one of the problems would be the limited distance that Wifi can travel; since it it running at 2.4GHZ while CB radio is typically around 26.965 MHz-27.405 MHz you won be able to transmit nearly as far as a CB radio could.

All things consider I do think that your idea is very interesting.

I did come across one site that does it commercially but it didn't really spark much because of the lack of detail on how their system works. [edit: www.packethop.com for anyone interested]

I thought of trying to get away from TCP/IP because of the addressing thing but then apps that normally use it would break then it came to me.. IPv6! (because a IPv4 Class A would be too small for something like this) Make the "ad-hoc" network IPv6, put the AP's in bridging mode (or if you got a WRT54g just compile it this way) and use something like Zebra http://www.zebra.org/ to function as the router in a OSPF configuration so it can refresh in near-realtime for every system on the network. Next hurtle would be some sort of DNS system that can work without centralized servers and can handle conflicting names (I figure IP's will be hardwired to prevent the lower level issue from happening).

As for distance... it would be entirely a case of density. In the city where people have wifi nodes setup, PDA's with wireless capabilities and other devices, the network would be alot like Wimax (which this could be applied to as well). The idea to me is a network that's not the internet. Plus, ham radio people can "boost" their radiation levels to get over the 300ft barrier. 802.11n will boost it another 150 feet at least with more bandwidth (but not at the same time).

Edited by jfalcon
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Neat idea, except for Part 15 limitations. Run under Part 97 and a whole world of possibilities open up, especially with D-STAR.

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When doing a certain urban explanation "mission" that required entering something in plain sight, we used the school's wireless to connect a Pocket PC to a streaming audio server, and got communications/alerts that way.

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Neat idea, except for Part 15 limitations. Run under Part 97 and a whole world of possibilities open up, especially with D-STAR.

Actually, that's what made me start thinking of it. I've been reading up lately on D-Star and HF Digital Voice and it reminded me of this thought I had way back when access points started catching on.

Last night I started thinking, "Wouldn't it be tight if like Amsat-Oscar Phase 3d (or something like it) had this going for it?" Even if it were on 3.4 ghz and people used transverters, it would create whole new worlds for ham radio in this era of "No-codeness" ;) It would have to be geosynchronous tho so not to have a doppler problem... or a frequency agile AP would need to be marketed.

But yeah, I don't think nearly enough experimentation has been done with hams and 802.11. Can the WRT54g/n be programmed to change frequency? If it could, then LEO birds could be used. Tho if it's hard locked to stay within the part 15 spectrum, some people might get pissy since it's outside the "AMSAT" portion. Band plans and people who mandate them upon the community are idiots needing to be first against the wall when the revolution breaks out.

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yea a car to car video link is very easy to setup, all you need to do is setup an ad-hoc network between the laptops in the cars that you wanna video conference with, or have one of the cars equipped with a wireless AP and have each computer connect to it, then use something like net meeting to video chat with each other. i would scrap the whole wifi thing all together because you would have to stay within range on the other cars in order to maintain a connection.when im on a long road trip and i wanna video chat with someone i just use my sprint pc card or tether my cell phone to my laptop for a steady internet connection, this way i can video chat with anyone anywhere, this just seems like a better solution IMHO. also i would disagree with the whole car accident thing, most traffic slowdowns are due to one or more lanes being shutdown as a result of the accident. and i dont think this really resembles bluejacking in any way.

While I'd admit that the sprint card is major convenient and there are/will be many commercial services now and in the future offering this sort of service, I brought it up more as a idea for "mesh-networking" movements. We're a long way from having utopian network coverage.

But I do find it odd that no one has gone to a low-level network layer and created a protocol/application that would allow people that share an access point to use them as communicators like CB or FRS/Walkie-Talkies that's independent of having a separate server. They are just data radios after all.

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I'm supprised no one has mentioned Car Whisperer:

http://trifinite.org/trifinite_stuff_carwhisperer.html

Basically the idea is that the 'hand-free' mikes built into cars are insure Bluetooth devices and can often just be connected to with a default pin.

The caller can then monitor the sounds from within the car or insert their own....

I was thinking that this would be a fun retail hack too. Set up in your local food court, and advertise 'Hummm, Donuts' to people walking past with Bluetooth earpeices. Wonder if you could cause a (food) fight? :-)

Mungewell.

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An ongoing idea we have around here is transverting 2.4 GHz Aerocomm FHSS wireless data modules down to around 430-440 MHz to overcome non line-of-sight and interference issues.

By changing the Aerocomm's country code, you can tweak the modules to just hop between something like 13 channels. On the 440 MHz side, it might be possible to adapt the RF power amplifier and receive pre-amplifier from old FRS radios for the front-end to the transverter. It'll need a good, clean 2 GHz LO, but that shouldn't be to hard.

They'll look like serial PPP or SLIP devices on the computer end.

http://www.aerocomm.com/

http://www.aerocomm.com/rf_transceiver_mod...transceiver.htm

http://www.aerocomm.com/rf_transceiver_mod...transceiver.htm

GBPPR Frequency Transverters for Wireless LAN Devices:

http://www.qsl.net/n9zia/trans/

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I've used Asterisk over WiFi. I've also used IRLP over WiFi. (By the way there is a Desktop mode that can take IRLP off the network and lets you use the native SpeakFreely to talk to it in a private network peer to peer type of way). You could use a WiFi phone or configure a DingoTel tway radio adaptor to talk over a WiFi connection.

I never thought about use a WiFi phone in stuck traffic like a CB... interesting thought, even more-so with the hot babe situation :-)

Asterisk over Wifi has a lot of possibilities. You can configure extensions to play podcasts on the fly, or your own virtual digital radio station, like XM.... Granted the audio isn't perfect for that, but you could mess with the codecs.

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