The Research On Handover Technology Under High-Speed Mobile Communication System Based On LTE-R

With the development of high-speed railway and the sharp increase of train running speed, the mobile communication system is required to ensure the communication quality of service in rapid mobile environment. The traditional GSM-R network has some limitations such as:the bandwidth limitation, low transmission rate with modulation technology. As the evolution of GSM-R, LTE-R has been a current research focus with advantages of large capacity, high transmission rate, smooth network structure and so on. As a key technique of LTE-R mobile communication system, the handover technique can ensure the seamless connection of communication systems, and the continuous communication. In this paper, we will study the handover decision algorithm and handover scheme, to improve the success ratio of connection and reduce the outage probability.Firstly, an adaptive union decision handover algorithm based on high-speed characteristic is proposed to improve the handover trigger probability and success probability, and decrease the BER. Based on high-speed mobile environment for railway, the RF model is established and parameters are determined. By analyzing the influence of decision standards on handover performance with high speed, An improved idea is proposed by analyzing the traditional decision algorithm and the performance of the union decision algorithm:RSRP handover margin dynamic adjustment method, RSRQ handover margin dynamic adjustment method and satisfied communication probability adjustment method, based which a union handover decision algorithm is proposed and analyzed.Secondly, a handover scheme based on smart antenna and resource reservation is proposed to improve the ratio of success and the communication quality. Considering the cellular coverage area where only one train is moving, we use the smart antenna which forms beamforming in the overlap, to improve the receive signal strength, and to ensure the communication connection and promote the trigger of handover. Furthermore, the pre-handover scheme is implemented to shorten the handover time by simplifying handover process when the train will obtained channel assignment from target cell before it arrives into the overlap.Lastly, the proposed handover decision algorithm and the handover scheme is valuated by simulations in Matlab to demonstrate the effectiveness of the scheme.