Interference across Multi-hop Wireless Chains

Chains or multi-hop paths are the fundamental communication structure in multi-hop wireless networks. Understanding chain behavior is critical in order to build effective higher layer protocols. This paper examines the problem of how MAC level interactions influence chain behavior in a general multi-hop wireless network where multiple chains coexist. We first classify chains based on the MAC interactions observed between its hops when there is no external traffic. Then we identify the interactions across two interfering chains for the most common categories of chains. We study the probability of occurrence, and estimate the effect of MAC interactions on the performance of the chains. We also show that different chains exhibit different transmission patterns; this is an effect that is necessary for accurately estimating chain performance. We observe that destructive interactions arise more frequently among two interfering chains than they do within a single chain. Moreover, chains that have hidden terminals due to self-interference are more prone to have cross-chain hidden terminals. Thus, both intra-chain as well as cross-chain interactions, ultimately provide significant insight into how chains interact.