Robust Optimal Power Control and Subcarrier Allocation in Uplink OFDMA Network with Assistance of Mobile Relay

Compared with the traditional fixed relay assisted communication network, the mobile relay assisted wireless communication network has greater communication coverage and better flexibility. It enables to extend the lifetime of a communication system and improve the throughput of uses. Due to the time-varying nature of the actual communication environment and the existence of various interferences, there are uncertain factors in the communication channel that affect the quality of service of users. In this paper, we study the energy efficiency maximization problem based on power control, mobile relay selection, and subcarrier allocation under uncertain channel. The proposed mobile relay selection and subcarrier allocation algorithm improves the energy efficiency of the system while ensuring the normal communication of mobile users. Probabilistic constraints are introduced into the optimization problem to describe the uncertain channel, and after the mathematical transformation, it becomes a solvable form. The subcarrier allocation algorithm and distributed robust power control algorithm are also presented. Simulation results show that the improved system energy efficiency has been achieved and the proposed algorithm behaves better scalability and robustness under dynamic communication environment.