Experimental analysis of broadcast reliability in dense vehicular networks

Dedicated short range communications (DSRC) enable novel automotive safety applications such as an extended electronic brake light (EEBL) or intersection collision avoidance (ICA). These applications require reliable wireless communications even in scenarios with very high vehicle density, where these networks are primarily interference-limited. Given the uncertainties associated with current simulation models, particularly their interference models, it is critical to experimentally validate network performance for such scenarios. Towards this goal, we present a systematic, largescale experimental study of packet delivery rates (PDRs) in a dense environment of 802.11 transmitters. We show that even with 100 transmitters in communication range with a frame size of 128 B and a bit-rate of 6 Mb/s, 1) most receivers can decode over 1500 packets per second (pps) in a saturated network, which corresponds to a PDR of 45% and 2) the mean PDR, for 10 pps per node workload that emulates vehicular safety applications, is about 95%. These results demonstrate that a COTS 802.11 implementation can correctly decode many packets under collision due to physical layer capture (PLC) and can serve as a reference scenario for validation of network simulators.