802.11p

[cryptorsa1001]

Anyone have any info on what will most likely be 802.11p? Did a google search that turned up a few morsels but nothing with any substance. This standard would be for wi-fi in moving vehicles.

[cjp]

Never heard of 802.11p. The notion of WiFi in car doesn't make much sense because if the AP is outside the car, the car will be confined to move within about 10 meters when the 802.11a PHY is used, and perhaps up to 100 meters when the 802.11b/g PHY is used. If the AP is inside the car, I don't see why it is so different to be inside a car than, say, a room. Also I don't know how the AP is going to connect to the outside world.

Are you sure you don't actually mean 802.16e, the mobile WiMAX?

-CJP

[badger11]

Check this out dude:

http://66.102.7.104/search?q=cache:zg5ROALjcBAJ:www.its.dot.gov/ivi/national_ivi/NatlIVIMtg_25Jun03-Fnl.ppt+802.11p&hl=en

The 802.11 WG has internal Study Groups looking at possible future standards for using Wi-Fi in moving vehicles (likely to become TGp, thus 802.11p)

Think about it, every car is a node transmitting and recieving data. The transmitted data could be the speed of your vehicle, wether your air bag has been deployed. You take all of that data and you as a driver will know that the speed of the vehicles 1 mile in front of you are going 5mph and someones air bag has deployed. Your gps map tells you to take the first exit as an alternate route. There are all sorts of benifits for us.

[cjp]

OK. I did a little study. It appears this "802.11p" thing points to the "WAVE" study group under the 802.11. So far, they are still in the stage of forming the task group. Since the "p" designator hasn't been used, it is very possible that the new task group may get it.

This study group apparently was "transplanted" from elsewhere with a goal to define something that is technical/economical feasible for the ASTM-E2213 spec (originated from the US Dept of Transportation for Intelligent Transportation Systems). According to the fact sheet of the spec, it is targeted at "high-speed data transfer at the 5.9GHz ITS-RS band" between vehicles and road-side services. Examples of the "road-side services" include toll collection, traffic management, traveller information, etc. The current 802.11 spec can not meet ASTM-E2213 requirement because the later may require the communication be established and transactions completed within orders of milliseconds.

So, I would guess this is definitely not for web surfing in the car, which I belive belongs to 802.16e. It is also not for the "low data-rate intra-vehicle communication" between, say, tires and dash-board. This, I believe, belongs to 802.15.4 (or Zigbee, depending on how you look at it).

-CJP

BTW, the "WAVE" stands for Wireless Access for Vehicular Environment. The term was created to replace the DSRC.

[badger11]

CJP, check this web site out.

http://www.meshnetworks.com/pages/applications/telematics.htm

Some of the technologies offered are very cool.

Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote! - Benjamin Franklin

[badger11]

is-136hs - provides support for vehicles which is part of 3G networking.

[cjp]

Hi Badger11, thanks for the information. It is certainly quite refreshing to see a company working on proprietary stuffs can still attract funding. Even though their employee-to-P/VP/chief ratio is less than 8:1 (according to their website), it appears their claims are not all hot-air balloons, especially after spending 170 mils of public money through DARPA.

To be frankly, I don't think they stand a chance if they intend to target their technology at the consumer market, where no more a company can single-handedly push its proprietary (and patented) technology into standard. They probably have a better chance if they keep their focus on government-related business, where things can be "regulated" in. This WAVE (or DSRC) certainly smells like something that can be built with public money.

Good luck and may the force be with them.

-CJP

[Anubis91]

802.11p is a new standard being developed in the 5.9 Ghz spectrum assigned for automotive communications. It will most likely be used in ad hoc mode, allowing vehicle to vehicle communication or vehicle to AP. Basically the topology will be mesh, which will also allow for real time vehicle telemetrics. The technology introduces the possibility of a nationwide adhoc/mesh wireless network allowing real time telemetrics including real time traffic reporting, vehicle positioning, and toll booth communications. The limitations previously mentioned concerning transmission distances really aren't an issue in a mesh network where every node serves as a repeater (of course this assumes wide adoption of the technology). There would also be the likelyhood of integration into chipsets already supporting a/b/g, which could allow bridging over different wireless networks (just my speculation).

[cjp]

I strongly doubt that 802.11p can be simply "dropped in" to the current (or even the next generation) chipsets without major tweaking of the designs. The problem is more than just getting a new synthesizer to tune in to the new 5.9GHz band, or a more powerful PA to extend the range. There will be significant changes to the baseband to handle new challenges such as fading that weren't problems before. There will also be changes in MAC to overcome problems caused by many "touch-and-go" type transactions in a short period of time. For example, based on the current IBSS spec, there is no easy way for the MAC to tell if a node has left the network.

-CJP