Cross-Layer Routing Protocols In Wireless Mesh Networks

Wireless mesh network is a new network structure with high rate and high capacity, which is based on multi-hop routing and peer-to-peer network technology. Wireless mesh network belongs to Ad hoc networks in nature. The biggest difference between them is user terminal mobility. Generally, wireless mesh network cannot act as an independent network, but as the last mile access network of internet. At present, the routing protocols used in wireless mesh network mainly come from the revision of classic routing protocol of the Ad hoc networks. The study of routing protocols of multi-radio multi-channel wireless mesh networks is still in the experimental research.This paper first introduces the characteristics of topology for wireless mesh network, and combined with the mobility performance of the node, chooses the OLSR routing protocol as research object. Secondly, we introduce the OLSR routing protocols and the design method of cross-layer routing in detail. And then, we propose a scheme in which radio interface switching, channel allocation and routing function of network layer is integrated in order to optimize routing protocol of cross layer. Finally, we describe the specific details and process of implementation of cross layer design with OLSR protocol, and propose an improved routing protocol called FC-OLSR.In the FC-OLSR protocol, wireless nodes compare the IDs of source node with the destination node, and choose Dijkstra algorithm to calculate the multiple paths which reach a certain node, in order to ensure that paths established by the node and destination node to each others are same. It chooses two paths with optimal performance by a revised routing metric called CSI-HOP. The selected path of the node is disjoint with the destination node through the scheme for the outward and return paths of the node, which can reduce the delay of switch time in intermediate nodes when the node is communicating with the destination. Finally, simulations based on the OPNET network simulation platform are used to evaluate the multi-radio multi-channel cross-layer routing protocol. The simulation results show that the performance of FC-OLSR is better than M-OLSR.