Handover Technology Research Based On Radio Environment Map Of High-speed Railway

The wireless communication system of high-speed railway is facing challenges including transmission reliability, efficiency in spectrum, power and energy consumption, device complexity, time delay and so on. So we build the train-ground communication system based on the high-speed railway radio environment map (HSR-REM). This system can store the information involving topographic feature, device configuration, path loss, channel property, electromagnetic interference and communication quality testing results along the railway to predict the results of channel and communication quality and to realize various adaptive and pre-processing technologies so as to ensure the high-efficiency, continuity, safety and stability of communications. The focus of this thesis is to design the handover technology based on the HSR-REM.Firstly, the REM and the train-ground communication system based on HSR-REM are introduced. Then the handoff process in GSM-R network and the handoff effect under the high-speed environment are discussed. Moreover, the handoff module based on the HSR-REM is described simply.Secondly, an improved handoff algorithm in GSM-R is proposed in the thesis which combines the new handoff condition decided by information of train’s location and speed obtained from HSR-REM with the traditional condition handoff initiation to achieve a handoff strategy ahead of time. Meanwhile, the REM can provide the train’s direction that can be used to obtain the target cell so as to avoid the happening of the ping-pong effect. The algorithm can not only improve the success rate, reduce the average handoff frequency between the two cells, but also save the handoff delay.Finally, the implementation of the train-ground communication system based on the HSR-REM is discussed in detail. Discussions on design of function, graphical user interface (GUI), class and database are provided. Further, the framework and handover module of HSR-REM train-ground communication system are implement by VC++6.0.