Research Of MAC Scheduling Mechanism And Routing Algorithm For Wireless Mesh Networks Based On Cross Design

Recently, as the developing of wireless communication technology, researching on Wireless Mesh Network has attracted more and more people’s attention and became a key technology of the next generation wireless network. As the key technologies of wireless Mesh network, channel access technology and routing technology play a decisive role of the overall performance of the network. In this paper, cross-layer designing of flat Wireless Mesh Networks is studied. MAC layer uses TDMA as channel access method which uses the network layer routing information to improve the channel utilization and reduce the lower-end delay. Besides, the network layer uses the information of the MAC layer to improve routing efficiency and reduce the routing overhead. Details are as follows:Currently, the existing mechanisms of channel access based on TDMA generally been designed alone, not associated with the routing layer. As having not consider the node load in the slot allocation process, the node allocated the same number slots no matter the node of heavy load or not which leads to reducing the channel utilization. In addition to, the order of slots and node position in a data flow path is not inconsistent lead the end to end delay increasing. In order to solve the problems, this paper improved the traditional classic P-TDMA algorithm. The improved algorithm(LLD-TDMA) joins the load information of nodes in the slot application process, which makes the node of weight load allocated more time slots. Also the improved algorithm uses the dynamic priority list in the slot allocation process, so each node competes slot becomes more equitable. In order to reduce the end to end delay, the improved algorithm uses the slot selection algorithm to adjust the order of slot in the slot selection process and makes it consistent with the order of node position in data flow path. Compared with the P-TDMA algorithm, the simulation results show the improved algorithm enhances 22.18% of the network throughput, improves 12.86% of the average node slot utilization, and decreases 23.9% of the end to end delay of data flow.Next, On the basis of analysis the broadcast storm, frequent routing problem of the traditional on-demand routing algorithm and the feasibility of cross-layer designing for the traditional on-demand routing algorithm’s performance improvement, this paper improved the traditional AODV algorithm based on the idea of cross-layer designing. The improved algorithm(CLC-AODV) makes use of the periodic interaction of RTS and RSP Packet in LLD-TDMA algorithm to establish local proactive routing, efficient reactive routing and rapid repair mechanisms. Compared to the combination of AODV and LLDTDMA algorithm, simulation results show that at mesh topology and node stationary scene the CLC-AODV and LLD-TDMA algorithm combination enhance 13.23% of network throughput and decrease 19.46% of routing overhead, at random topology and nodes are randomly moving scenes enhance 17.91% of network throughput and decrease 23.21% of routing overhead.