Resource Allocation Algorithms For Cooperative Communication In Multi-hop Wireless Mesh Networks

With the improving performance of wireless mobile terminal equipment, to provide users with high-bandwidth, high-quality Internet access service has become an urgent demand. Wireless Mesh Networks use multi-hop technology to achieve low-cost, large coverage, and automatic wireless access, which is expected to become the standard of the next-generation wireless access network. However, there still exist many issues to be resolved for wireless mesh network, such as the transmission signal fading of the node produced by the environment and distance, the reduced path effective bandwidth with the increasing of the number of hops and the network performance degraded by competition between links.Cooperative communication technology utilizes the broadcast nature of the radio channel to cope with the channel fading effectively, thereby enhancing wireless transmission rate, reliability, effective bandwidth and communication expansion. The applications of cooperative communication technology in wireless mesh network can further optimize the structure of wireless mesh network and enhance network performance. However, it also brings new challenges, especially in multi-interface wireless mesh network with more complicated interference relationship and resources allocation involved, such as relay selection and interface allocation. This paper focuses on the research of cooperative node selection and interface distribution for data streams in cooperative Wireless Mesh Networks, the main work and innovation are stated as follows:To maximize the network reliability, a contention based relay selection algorithm is proposed for multi-stream multi-hop wireless networks based on cooperative communication. In the algorithm, firstly, a cooperative node with the highest reliability is assigned to a link in a stream, then the nodes in the competition state are assigned to the bottleneck link with the maximum gain of the reliability and it have no another available relay node, finally, for the other links which compete this relay node will reselect a idle node for cooperation. It is an effective way to assign an optimal cooperative node for each link of streams, as a result, it can deal with the competition issue of the cooperative nodes between and in the data stream appropriately. Simulation results show that the algorithm can significantly improve the reliability of network transmission in wireless network with multiple data streams.The issue of maximizing the reliability of network transmission is modeled as an integral nonlinear programming problem for multiple-data streams in multi-interface wireless Mesh network. And proposes an algorithm which joint cooperative relay selection and a Branch-and-Bound based cooperative interface assignment(JRSIA) in this paper. JRSIA algorithm firstly determines the transmission mode for each link in flows and chooses relay node for cooperative links, and then allocate interfaces for each link according to its transmission mode to maximize the system’s reliability of all flows. This algorithm can fairly allocate interfaces to direct transmission and cooperative transmission, which can increase the transmission reliability by using the cooperative transmission gain.Simulation results show that the algorithm proposed in this paper can improve the network throughput, reduce the network latency and the packet loss rate. It can improve the network performance effectively.