Research On The Backbone Link's Transmission Performance Of Railway Wireless Mesh Network

The Railway Wireless Mesh Network ( RWMN ) based on banyan-tree topology combine the advantages of bus topology with the advantages of star topology, and give a more reasonable solution to dispose the Internet along the railway. However, the performance of Wireless Mesh Network (WMN) is decreasing rapidly as the wireless hops increasing. The RWMN is based on the development of WMN and its wireless hops of backbone link are always up to tens, Although the multi-radio Mesh technology highly improves the transmission performance of RWMN , the research shows that the multi-hop transmission bandwidth is decreasing obviously as wireless hops increasing. So it is necessary to give in-depth research and find out the pivotal factors which affect the backbone link's transmission performance, then improve the application performance of RWMN.For this reason, this thesis sets up a network traffic model and a analysis model of transmission performance for the backbone link of RWMN, which based on the banyan-tree topology, then analyses the main factors which affect the transmission performance and find the main research directions to improve the multi-hop transmission bandwidth. A simulation test bed of backbone link is constructed which based on the betterment to NS2, and series of simulation experiments are performed with the test bed to analyse many influencing factors, such as wireless interference, wireless signal strength and packet processing capacity. Finally, two wireless routers M-Router which based on embedded platform and x86 platform are manufactured with the Linux open source coding. Based on the M-Router, A test bed of backbone link is constructed, and in-depth experiments are performed with the test bed. The results of theoretical analysis, simulations and experiments prove that packet processing capacity and wireless interference are the key factors which affect the backbone link's transmission performance of RWMN, so it is possible to optimize the performance by enhance CPU processing capacity, adopt ahdemo mode and orthogonal channel multiplexing scheme.This thesis take an analysis and research on the factors which affect the multi-hop transmission performance of RWMN, then it come up with some ideas and solutions to enhance the transmission performance and lay the foundation for next study simultaneously.