A specific mobile relay with Doppler diversity in OFDM system for high-speed railway scenario

Relay is considered as an effective method to improve the coverage of high data rates, group mobility, temporary network deployment, and cell-edge throughput and provide the coverage in new areas. Mobile relay station (MRS) is considered as an extension of fixed relay in mobile scenarios such as bus, car and train. Doppler diversity is a diversity technique to improve reliability in highspeed scenario, which has been discussed in recent years. However it is so complicated that may not be suitable and economical for MS. This paper proposes a scheme about the combination of mobile relay station with Doppler diversity in OFDM system communications for high-speed railway scenario. This scheme can provide good quality in relay-MS link in which MS is at low or no velocity. System performance has been evaluated. Several other environments, which include non-relay systems, mobile relay without Doppler diversity system, are considered in this paper to be compared with this scheme. Moreover, fading channel model is analyzed and WINNER II channel model is used as the basic channel model for the simulator.