Efficiency and Reliability of One-Hop Broadcasting in Vehicular Ad Hoc Networks

In Dedicated Short Range Communications (DSRC) based vehicular networking, each vehicle periodically broadcasts control updates (that contain location and speed information etc.) to its neighbors, as a key component of traffic management and safety applications. The effectiveness of such a broadcast feature can be measured by two metrics: (1) the efficiency, or the average rate (number of nodes per sec) to which a source can deliver its broadcast packets, and (2) the reliability, or the average number of nodes that receive a specific transmission successfully. We demonstrate theoretical limits to and achievable tradeoffs between efficiency and reliability for a linear network under Rayleigh fading links. We then provide power control and congestion control strategies that maximize broadcast efficiency. A strategy that achieves near-optimal broadcast efficiency when the network nodes have high mobility is also described. Ns-2 simulations are used to validate our analytical results.