Contention Control for High End-to-End Throughput Performance of Multihop Wireless Networks
Hyuk Lim, Daewon Jung, Jaeseon Hwang, Kyung‐Joon Park, Jennifer C. Hou · 2007
In multihop wireless networks, packets of a flow originated from a source node are relayed by intermediate nodes (relay nodes) and travel towards the destination along a multihop wireless path. Since the traffic forwarding capability of each node varies according to its level of contention, a node should not transmit excessive packets to its relay node if the corresponding relay node cannot forward them. Instead, the node should yield its channel access opportunity to its neighbor nodes so that all the nodes can evenly share the channel and have similar forwarding capabilities. In this manner, nodes can utilize the wireless channel effectively, and further increase the end-to-end throughput of a multihop path. We propose a fully distributed contention window adaptation mechanism, which adjusts the channel access probability depending on the difference between the incoming traffic and the outgoing traffic at each node, in order to equate the traffic forwarding capabilities among all the nodes in the path. If the incoming rate of a node is larger/smaller than its outgoing rate, the forwarding capability of that node should be increased/decreased so as to match the outgoing rate with the incoming rate. In the proposed mechanism, a node is granted to increase/decrease its channel access probability if its traffic forwarding capability is worse/better than those of competing neighbor nodes. We give a convergence analysis of the proposed scheme as well as its steady-state performance. Through simulation, we show that the end-to-end throughput of multihop wireless path can be improved by 20–40 % under variety of network topologies and traffic patterns.