Analysis of the Uplink Capacity in the High-Speed Train Wireless Communication with Full-Duplex Mobile Relay

One primary challenge in the high-speed train (HST) communication is that the wireless signal suffers from severe attenuation while it penetrates the sealed carriage of the train. In this letter, we show that such a nuisance can provide an opportunity of improving the uplink capacity when a full-duplex (FD) mobile relay (MR) is furnished on the train. To this end, by introducing the self-interference cancellation (SIC) level, we present an uplink channel model for the HST communication with FD MR. Then the uplink capacity is analyzed under either user equipment power constraint or total power constraint. By comparing with time division scheme, we can derive the required SIC level for the FD scheme to bring capacity improvement, which is confirmed by numerical results. Furthermore, theoretical analysis shows that, for a given SIC level, the uplink channel with severer carriage attenuation has higher capacity, which is also validated by numerical results.