Energy Efficiency Optimization of Ultra-Reliable Low-Latency Communication for High-speed Rail

With the rapid development of new communication technology, notably ultra reliable low latency communication (URLLC) in the 5th generation cellular network, and the wide deployment of high-speed rail (HSR), it becomes critically important to enhance the energy efficiency of the HSR communication system by optimally allocating the bandwidth and transmit power for users, while ensuring the quality of service (QoS) requirements of URLLC. In this paper, we tackle this challenging resource allocation problem of the URLLC system for HSR. Specifically, we establish the train-ground URLLC model for the HSR communication system with mobile relays (MRs), based on which we formulate the optimization problem with the QoS requirements of URLLC as constraints for maximizing the system's energy efficiency. By decomposing this challenging optimization problem into two subproblems, a heuristic algorithm is adopted to optimally allocate the transmit power and bandwidth of users with the block coordinate descent (BCD) approach. The simulation results show that compared with the existing algorithms, the proposed algorithm achieves better performance in resource allocation optimization of user bandwidth and transmit power.