Performance of multihop wireless networks

Abstract

Existing wireless ad hoc routing protocols typically find routes with the minimum hop-count. This paper presents experimental evidence from two wireless test-beds which shows that there are usually multiple minimum hop-count paths, many of which have poor throughput. As a result, minimum-hop-count routing often chooses routes that have significantly less capacity than the best paths that exist in the network. Much of the reason for this is that many of the radio links between nodes have loss rates low enough that the routing protocol is willing to use them, but high enough that much of the capacity is consumed by retransmissions. These observations suggest that more attention be paid to link quality when choosing ad hoc routes; the paper presents measured link characteristics likely to be useful in devising a better path quality metric.

Generic Routing Metric and Policies for WSNs

“…Let us discuss three representative examples. The Shortest Path First metric (SPF) discussed in [3,6] selects the route based only on path length information. It has been shown to be not suitable for sensor networks, since it selects the neighbor further away with the lowest link quality to route packets.…”

“…An optimized version of it, called SPF(t), applies a blacklisting procedure to filter the links with quality less than t before using the SPF algorithm on the resulting topology. Clearly, SPF(t) shows better behavior than SPF, but it might lead to a disconnected routing tree, as shown in [6]. The Success Rate (SR) metric tries to find the paths with the highest end-to-end success rate as a product of link qualities p ij along the path P ath:…”

A QoS-Aware Ad Hoc Wireless Network for Isolated Rural Environments

“…It has been established that proactive protocols are not well suited for ad hoc networks where the throughput is considered a critical resource because routing table broadcasts may starve all available resources. But even reactive protocols whose metrics is the number of hops have some important limitations in wireless networks [4]. A wireless link in a 802.11b network may have a speed as of 1,2,5.5 and 11 Mbps, but the real throughput is much lower because it depends on the quality of the signal, which may vary with the distance and the presence of interferences.…”

E²R: Energy efficient routing for multi-hop green wireless networks

“…In order to overcome link instability and utilize broadcast benefit in wireless networks, some opportunistic routing protocols ( [5], [3], [2], [26]) have been proposed. However these opportunistic routing protocols pre-select forwarding candidates beforehand and the selection of an appropriate forwarder list is not trivial especially for multiple sourcedestination pairs in a large scale multi-hop wireless network.…”