Research And Implementation Of A Wireless Mesh Hybrid Routing Protocol Based On Link Detection

Wireless Mesh Networks(WMNs), as an option of the last mile broadband access, has the advantages of Wireless Local Area Networks(WLANs) and Ad Hoc networks. It possesses the property of self-organizing, self-configuring and self-healing, can provide a large-capacity, high-speed and wide-range network coverage with a lower initial investment, and supports users with non-line communications in static and dynamic mode.Routing protocol is a key technology of WMNs, which determines how the datagram is transmitted. A good routing protocol can promote the network capacity, reduce the end to end delay and jitter, and improve the quality of communication. On the basis of synthesizing the advantages of proactive, reactive and hybrid routing protocol, the thesis proposes a hybrid routing protocol which is based on Optimized Link State Routing (OLSR) and Ad-hoc On-demand Distance Vector (AODV) routing. Traditional OLSR and AODV protocols only consider the path hop as routing metric. So they can't solve the problems of link congestion and decrease in communication quality, which are caused by link quality deterioration and node overcrowding. By reading a large number of researching results from home and abroad, we introduce a Link Congestion Factor(LCF) and a Link Break Factor (LBF) to timely detect the node congestion level and link quality. When calculating routing table, the routing metric is composed of LCF, LBF and path hop, thus the routing protocol could support Quality of service(Qos) and realize load balance. The hybrid routing protocol comprises of intra-zone Link Detection OLSR(LD-OLSR) and inter-zone Link Detection AODV(LD-AODV) protocol. Each node running this hybrid routing protocol will calculate real-time and non real-time routing table, that could fully guarantee the Qos by different kinds of service character. In addition, the thesis also introduces a routing error (RERR) message in order to achieve self-repairing route.The key of the thesis is to realize the routing protocol, so from chapter two, we elaborate the realizing procedures of the wireless Mesh hybrid routing protocol based on link detection. First, the thesis introduces an overall design and a sub-module division of the protocol, and gives the designs of timer handling and control message scheduling. Then, we make a detail analysis of system implementation of the LD-OLSR and LD-AODV protocols in aspect of the data structure designing, the frame structure describing, the control message processing, and the routing table calculation, etc. Finally, we provide a system testing and the performance simulation of this protocol. The related test and simulation results show that the design of wireless Mesh hybrid routing protocol based on link detection could provide a better service experience and Qos guarantee, and the software system developed based on this routing protocol works well that can be applied in the actual devices.