QoS-distinguished achievable rate region for high speed railway wireless communications

In high speed railways (HSRs) communication system, the wireless channel between the train and base station varies strenuously due to high mobility, which makes it very essential to implement appropriate adaptive algorithms to guarantee the quality-of-service (QoS). What´s more, how to evaluate the performance limits in this new scenario must also be considered. To this end, this paper investigates the performance limits of wireless communication in HSRs scenario. Since the information transmitted between train and base station usually has diverse QoS requirements, a QoS-distinguished achievable rate region is utilized to characterize the transmission performance in this paper, which can be regarded as a generalized case of traditional ergodic capacity and outage capacity with unique QoS requirement. The specific adaptive algorithm that can achieve the maximal boundary of achievable rate region is also derived. Compared with conventional strategies, the advantages of the proposed strategy are validated in terms of green communication, namely minimizing average transmit power.