Research On WMPLS Technique Application In Railway Emergency Network Routing Algorthm

Nowadays, the railway industry of our county is in fast development period, Various techniques are applied in railway construction. As the development of railway industry, RRCS(Railroad Communication System) also has a great leap. Today communication signal integration is popular in RRCS, GSM-R(GSM for Railways) RRCS platform which based on cellular mobile telecommunication is being widely promotion and used. Focus on the railway transportation status of our country, the techniques of GSM-R are improved and completed incessant. GSM-R communication platform rely on BS to relay datas, when BS destroyed by driving accidents or natural disasters, the BS can not provide normal mode services for GSM-R HTs to communicate with each other, the GSM-R HTs change their communication mode to Ad hoc networking mode, using Ad hoc networking technology characteristics to achieve GSM-R HTs arranging more quickly and covering wilder, giving more powerful guarantee to railway emergency communication.Firstly, Analyzing the GSM-R HTs working mode. Focusing on the characteristic of DMO(Direct Mode Operation), combining with personnel organization structure and movement rules in the emergency site, using the clustering structure of Ad hoc networking, to avoide the poor expansion of the flat network structure which may cause network congestion. To achieve the aim of isolating communication between inter-cluster and intra-cluster, clustering-based networking can decrease the flooding of routing discovery control packets in the whole network effectively.Secondly, Based on clustering idea choosing a mature Clustering-Based Routing Protocol as the Ad hoc emergency communication networking protocol. According to the characteristic of WMPLS technique, using a fixed length label as forwarding symbol, combining the label with CBRP clustering routing algorithm can improve the data forwarding efficiency. In order to achieve the label switching of data packets, researching on CBRP routing algorithm and choosing labels carrying type to distribute, adding labels to the RREQ and RREP packets, as setting up forward route and backward route complete the label distribution, and build the label switching path. Wireless MPLS combine with CBRP, improve the CBRP routing algorithm, propose an concept LSCRA, using label switching of 2nd layer instand of IP switching of 3rd layer.Once more, researching on the railway emergency site, using NS2 simulator to experiment, choosing different network scales and different network loads as the simulation parameters, to test the improved algorithm, according to the movement of person whom work in the emergency site to choose simulation mobility modle, the results of simulation show that LSCRA has better performance than CBRP in Network Delay, Packet Loss and thoughput. Finally, comparing with QoS index of GSM-R, to check the applicability of the LSCRA routing algorithm, summing up the whole thesis and discussed its development direction..