Researches In Load Balance Scheme In Wireless Mesh Networks

With the rapid development of wireless communication and information networks, wireless mesh network can be the last mile broadband access solutions, which have broad application prospects in the military, environment, medical, family and many other fields. Because, of its wireless multi-hop relay characteristics, the increasing number of customers will cause the limited of network bandwidth and network capacity resources. How to build a reliable access to Internet on the basis of performances of throughput, latency and packet lost rate is a key factor of real mesh network application. For load balancing schemes can. improve network capacity, balance network resources, make nodes with higher throughput and enhance the bandwidth utilization, research on load balance schemes have great significance.Firstly, current load balance algorithms and their limitations in wireless mesh network were introduced. Then common problem in existing load balance was analyzed, that is the central load and gateway load issues. Based on mesh topology, this thesis uses the concept of network load model, puts forward a virtual Grid based Load Balancing Routing algorithm named as GLBR. GLBR includes three phrases: grid load status broadcasting, routing grid selection and route maintenance. The load of link in a grid will be the standard of the grid load. In routing grid selection, consider the node location information and grid load information, then select the small load grid to route, in this way, packet data can arrive to destination avoiding congestion area in network. GBLR use the way of grid to grid routing. Furthermore, this thesis analyses route loop problem in GBLR. Route loop problem can be avoided through controlling data packet. Simulation results show that GLBR can improve load balance and increase the throughput of the network, and also reduce the packet loss rate.Aim to muti-path routing, the thesis designs a Forwarding Probability based Load Balance Routing algorithm (FPLBR). The algorithm combines with the grid location and the grid load information defining grid forwarding probability, which can avoid the congested grid becoming a forwarding grid in a new path. A route selection strategy is used for FPLBR in order to set up link-disjoint multi-path between source node and destination node. A flow distributed strategy is used to make the date traffic load more evenly on every link-disjoint path. Simultaneously through transmitting the data packet on multiple paths parallely, the load of network is balanced well. Finally, we evaluate the performance of FPLBR. Simulation results show that the proposed algorithm has obvious advantages compared with DSR and SMR in packet loss rate, end-to-end delay and throughput of the network.