Adapting statistical broadcast to linearly oriented networks for VANETs

Broadcast is a critical component in ad-hoc wireless networks. Some vehicular network (VANET) applications in particular use broadcast communications extensively. VANETs exhibit a wide variety of node density and distribution patterns, so broadcast protocols designed to support these applications must be adaptive to those conditions. We show that the distance method of statistical broadcast can be used to design a protocol that performs well in one-dimensional or two-dimensional uniformly distributed networks, but not both. We propose using the quadrat method of spatial analysis to characterize the distribution pattern at each node and use the resulting metric, K, as a factor in computing the statistical threshold function. The result, the Distribution-Adaptive Distance (DAD) method, is shown to exhibit a high level of reachability and efficient bandwidth utilization across a range of distribution patterns from purely linear to purely two-dimensional and sparsely distributed to densely distributed. More generally, the design methodology presented in this work provides a procedure enabling statistical broadcast protocol designers to build protocols that are adaptive to both node density and node distribution. This capability is a key prerequisite for design of practical broadcast protocols to support VANET applications.