The fundamental role of hop distance in IEEE 802.11 multi-hop ad hoc networks

Abstract

In wireless networks, it is well understood what throughput can be achieved by nodes who can hear each other (i.e. nodes within a single cell). The effects of nodes beyond the sensing range (known as hidden nodes) on a sender are complicated and difficult to analyze. Consequently, how to analytically model multi-hop ad-hoc networks, specially networks based on the popular IEEE 802.11 standards remains largely open. In a recent paper, the throughput of a particular wireless network topology (linear network with a given number of hidden nodes) has been derived analytically. In this paper, we unify previous results on single-cell models, and results characterizing different types of hidden node interference and the analysis of C. Ng et al., (2004), to derive a general solution for throughput given a linear network of arbitrary density and transmission distance between source and destination nodes. An important insight from our model is that there is a certain transmission distance, which is less than the maximum transmission distance, that optimizes throughput in such networks. This result is verified using ns-2 simulation with both single as well as multiple flows.