Abstract-In this paper, we propose a new metric that is applicable both to routing and rate adaptation in multirate wireless mesh networks. Unlike many previous efforts, our metric is comprehensive; it considers several factors that affect end-to-end performance such as the effect of the relative positions of the links on a path when choosing the rates of operation and the importance of avoiding congested areas. We call our metric ETM (for Expected Transmission cost in Multi-rate wireless networks). We analytically derive the ETM metric. We show that the ETM metric can be used (a) to determine the best end-to-end path with a greedy routing approach and (b) it can be used to dynamically select the best transmission rate for each link on the path via a dynamic programming approach. Based on ETM, we design and implement the ETM-framework on an indoor wireless mesh network and compare its performance with that of the popular ETT and the recently proposed ETOP metrics. Our experiments show that the ETM-framework yields throughput improvements of up to 253% and 368% as compared with the ETT and ETOP frameworks. The goal of this work is to maximize the end-to-end throughput of flows in a multi-rate wireless mesh network. The throughput depends on a number of factors that should be considered jointly during the selection and management of a route. To our best knowledge, no previous work addresses together the issues of: (a) the selection of a path, (b) link rate adaptation on a per path-basis (and not per link in isolation), and (c) the effect of competing flows in the network. We discuss each of these issues below. a. Path selection: The routing metric should capture the influence of all of the following interdependent factors that affect the end-to-end throughput: (a) the number of links on the path, (b) the achievable rates on these links and, (c) the relative positions of the links on the path. The last factor is a direct consequence of (i) the typical use of a finite number of retransmission attempts at the link layer (as with 802.11) and (ii) as many transmissions as needed to deliver the packet with a reliable transport layer protocol (such as TCP) [1] ; packet drops closer to the destination induce end-to-end (e2e) retransmissions on links that were successfully traversed in previous e2e attempts and this increases the load and thereby congestion. Previously proposed routing metrics (such as [2] , [1], [3]) account for a sub-set of the above factors; to the best of our knowledge,
ETM REF routing metric captures number of links, link rates, success probability and link position along routing path.
A Unified Metric for Routing and Rate Adaptation in Multi-Rate Wireless Mesh Networks
2011 IEEE Eighth International Conference on Mobile Ad-Hoc and Sensor Systems
2011 IEEE Eighth International Conference on Mobile Ad-Hoc and Sensor Systems
Computer Science