Joint Channel Access and Power Control Optimization in Large-Scale UAV Networks: A Hierarchical Mean Field Game Approach
Runfeng Chen, Jin Chen, Haichao Wang, Xiaobing Tong, Yifan Xu, Nan Qi, Yuhua Xu
Abstract
With the development of the new generation communications, unmanned aerial vehicle base stations (UAV-BSs) have been widely used to enhance the terrestrial communications. Because of the increasing demand for communication, the scale of the networks is constantly expanding. This paper investigates a joint channel access and power control optimization in large-scale UAV coverage networks, and proposes a hierarchical mean field game approach. Firstly, considering the quality of service (QoS) requirement and energy consumption, the cost function of UAV-BSs is designed. A joint channel access and power control optimization framework is built to improve the efficiency of resource utilization by minimizing the cost function. Then, the joint optimization problem is formulated as a hierarchical game model whose exterior is a channel access game and interior is a multiple mean fields game (MMFG). The channel access game is proved to be a potential game and have at least one Nash Equilibrium (NE). As feedback for channel access optimization, power control policy is obtained by MMFG. A near-optimal algorithm for joint optimizations is designed to achieve the NE. Besides, aiming to the networks with limited computing capability, we also propose a fast optimization approach. The original optimization problem is divided into two independent sub-problems. The channel optimization sub-problem is formulated as a local altruistic game model, then the power policy sub-problem is solved by MMFG. A distributed algorithm based on spatial adaptive play and better response is proposed. Finally, the simulation results verify the validity of the proposed algorithms. The near-optimal optimization method has a better performance while the fast optimization method has a higher speed of the convergence. Compared with the traditional approaches, both of them improve resources utilization efficiency greatly.