Radio Environment Maps for VANETs?

The unreliable wireless link is perhaps one of the biggest obstacles to implementing cooperative safety functions using V2V communication. At 5.9GHz, the standardized frequency band for ITS applications in many countries, the effects of for example shadowing could be severe. Sure, more advanced radios using better coding techniques could help in a lot of scenarios, a while ago we wrote about such tech from Australian company Cohda Wireless. However good there will most likely still be corner cases where features of the terrain or buildings conspire to create radio "black-spots".

What I am interested in is to let the network learn by observing and recording communications quality as a function of location. This information would then be used to allow app developers to place requirements on communication quality. This idea is not completely new though, in the cognitive radio community adapting to the observed state of the wireless medium is one of the core tasks.

A quick literature search turns up quite a lot of publications on something called "Radio Environment Maps" (REM) by researchers at Virginia Tech. A REM in this context is basically a database of everything of interest to a cognitive radio, such as spectrum regulations, locations of primary users as well as past experience of nodes in the network. Although the authors mention several applications I believe they have the classical cognitive radio application in mind, spectrum scavenging. In the VANET case, the functionality of the existing (fixed spectrum) communications technologies as a function of location would be in focus.

The VANET REM I envision would have to be very detailed, i.e. so that communication quality between relevant pairs of locations could be looked up. My idea is to piggyback the data collection on top of the standard periodic beaconing protocols suggested for VANETs. An aggregation infrastructure could then be used to build the maps themselves.