Research On Coordinated Multi-Point Transmission/Reception In High-speed Railway Scenario

In recent years, the construction of the highspeed railway in our country is developing rapidly, not only the mileage, but also the running speed has reached the world’s best level. Although high speed has brought great convenience to the travel of people, it also brings new challenges to the reliability and efficiency to railway wireless communication system. Poor communication quality at cell edge and the lack of frequency resource have been serious problems in railway communication. The single cell transmission system can hardly meet the demands of the business requirements in high-speed railway scenario. In public communication scenario, Coordinated Multi-Point Transmission (CoMP) can develop the communication quality at the cell edge by sharing the data information and the channel information of users in multiple coordination cells, and has been a hotspot in recent years. However, the high-speed railway communication scenario has a lot of differences from the public communication scenario, such as complex radio scenario, frequent handover, large Doppler shift, ect. Therefore, it is necessary to research CoMP in high speed railway scenario, and research the applicability of CoMP in high speed railway scenario.The work and innovations of this thesis are listed as follows:First, the selection of coordination cells, coordination schemes, feedback methods and coordination range in CoMP are researched, and the advantages and disadvantages of coordinated scheduling/beamforming and joint processing are compared;Second, several common radio propagation environment in high speed railway scenario and the handover and Doppler shift problems caused by high speed are discussed, the applicable wireless channel models in high speed railway scenarios are concluded, and the applicability of CoMP in high speed railway scenario is analyzed by simulation;Third, the codebook based opportunistic beamforming (COBF) is researched, and the capacity and bit error rate of COBF in wideband channel is analyzed;Fourth, a multi-cell beamforming method is researched, and the impact of codebook size, feedback delay and antenna number to system performance is analyzed.