An Adaptive QoS Path Selection Algorithm based on Environment-Aware for Wireless Mesh Networks

With the rapid development of the wireless Multi-hop Mesh networks, more and more wireless multimedia services have high demands on bandwidth, delay and jitter to improve overall system performance. In this paper, an adaptive adjustment strategy of the MAC (Media Access Control) layer maximum retransmission count is developed by means of statistical information of wireless channel state and link quality, to reduce wireless link collision probability and improve the packet successful delivery rate of wireless Mesh networks. The adaptive adjustment strategy takes into consideration packet loss property of the MAC layer and PHY (Physical) layer over wireless networks, and distinguishes the causes of packet loss for wireless link (wireless link random error or network congestion/conflict) based on environment information by use of stratified analysis method to predict the best retransmission count of the MAC layer for each packet that should be retransmitted. In the network layer, based on adaptive retransmission strategy of the MAC layer and statistics of path state, a heuristic environment-aware QoS (Quality of Service) dynamic routing optimization algorithm HEAOR (Heuristic Environment-Aware Optimal Routing) for IEEE 802.11 wireless Mesh networks is proposed. The proposed heuristic scheme can adaptively select optimal path based on dynamic aware of bottom layers link information by means of gray correlation analysis method to improve routing efficiency and reduce the probability of packet loss without increasing the routing computational complexity. NS2 simulation results show that the proposed optimal routing selection scheme can reduce rerouting frequency and link failure probability, and is effective in improving throughput and reducing end-to-end delay. The proposed scheme enables us to find optimal the MAC layer retransmissions and select an optimal path over error-prone wireless links.