The Research Of Congestion Control Mechanisms In Wireless Mesh Network

Wireless mesh networks is one kind of wireless network consisting of mesh backbone network formed by mesh routers to support wireless access and transmission of mesh terminal nodes. Wireless mesh network has advantages of flexible architecture, rapid deployment, self-organization and self-healing, and has broad and promising application prospect. However, wireless mesh network's multi-hop transmission, the limiting resources of nodes, the lack of wireless bandwidth and the dynamic topology easily lead to network congestions. Hence, the congestion control is an important issue in Wireless mesh networks.The main work of this paper is following:(1) Investigating the congestion control performance of the data transfer with the existing network protocol. Performing the modeling and simulation in Wireless mesh network by using NS2with the IEEE802.11MAC and AODV routing protocol, and assessing the performance of the data transfer, with the scenes of UDP, TCP, and hybrid scenes in chain topology. The potential approaches to enhance the performance of real-time data service in wireless mesh network are discussed.(2) Proposing the enhanced algorithm on congestion control of wireless mesh network. In order to improve the transmission performance of the Wireless mesh network, a hop-to-hop feedback congestion control algorithm is proposed based on the MAC layer referring to the IEEE802.11s protocol and congestion control mechanism of the TCP. The algorithm differentiates the congestion and non-congestion packet loss, and jointly measures the congestion by MAC layer interface queue occupancy and MAC layer reverse back-pressure. The congestion information is sent to the upstream node hop by hop, and the nodes take the appropriate rate adjustment strategy according to the different level of congestion. The performance is simulated by using NS2for both chain topology and grid topology, and the results demonstrate the effectiveness of the enhanced protocol in dealing with congestion in the wireless mesh network.