HIAM : hidden node and interference aware routing metric for multi-radio multi-channel wireless mesh networks

Abstract

In wireless mesh networks, throughput degrades dramatically as the network grows due to two main problems: the hidden node problem and the carrier sense interference. These problems can be solved in multi-channel multi-radio networks by choosing a path consisting of channels that reduce the carrier sense interference and the hidden node problem. In this paper, we propose a new routing metric, Hidden node and Interference Aware routing Metric (HIAM) that considers the hidden node problem and the carrier sense interference for choosing the paths. The hidden node problem for a path is represented by estimating the packet transmission time with respect to the number of collisions happened due to hidden node problem over that path. The carrier sense interference for a path is represented using an extended Weighted Cumulated ETT (WCETT) to obtain the packet transmission time with respect to inter-flow interference, intra-flow interference, and retransmissions caused by carrier sense interference. Hidden node problem has higher effect on throughout degradation than carrier sense interference; Simulation results show that HIAM achieve approximately six times lower number of dropped packets and broken links than Expected Transmission count metric (ETX) or WCETT, and six times higher throughput than ETX or WCETT. Furthermore, HIAM can handle effectively higher number of concurrent flows, more than 15 flows, than ETX or WCETT in highly loaded 20-node network. The control packet overhead ratio of HIAM is much smaller than ETX and WCETT.