面向能效的低轨卫星联合跳波束调度和功率分配算法

该文针对低轨(LEO)卫星载荷容量受限且功率资源稀缺的问题，面向搭载跳波束(BH)天线的低轨卫星通信系统，提出一种联合跳波束调度和功率分配机制，在满足用户服务质量需求的前提下降低卫星通信载荷功耗，提高卫星通信系统能效。首先建立时延受限下联合考虑波束调度和功率分配的卫星功耗最小化模型。针对网络拓扑的时变特性，基于李雅普诺夫优化方法，将原多时隙优化问题转化为单时隙优化问题，然后采用交替优化的方法获得单时隙问题的次优解。其中，证明波束调度子问题是凸问题，同时通过逐次凸近似和对数变换将功率分配子问题转为凸问题，并提出相应算法获得子问题最优解。仿真结果表明，提出的策略在保证用户平均时延要求的同时，降低了低轨卫星系统平均功耗，并且可通过调整控制参数实现时延和功耗的动态平衡。

Joint Beam Hopping Scheduling and Power Allocation of LEO Satellites Oriented Energy Efficiency

In Low Earth Orbit (LEO) satellite networks, the capacity of satellite payload is limited strictly, and onboard power resource is extremely scarce. Thus, a joint Beam Hopping (BH) scheduling and power allocation scheme is proposed to reduce onboard power resources consumption for the LEO system with BH antennas, while meeting quality of service requirements of users, so that the energy efficiency of the satellite communication system can be improved. Firstly, the joint beam scheduling and power allocation problem with delay constraints is formulated to minimize the power consumption of the satellite system. Considering the time-varying topological characteristics of the system, the original multi-slot optimization problem is transformed into a single-slot optimization problem based on the Lyapunov optimization method, and then the alternate optimization method is employed to obtain the sub-optimal solution of the single-slot problem. Specifically, the beam scheduling subproblem is proved to be convex, the power distribution subproblem is transformed into convex by successive convex approximation and logarithmic transformation, and the corresponding algorithm is proposed to obtain the optimal solution of the subproblems. Simulation results show that the proposed scheme can reduce the onboard power consumption of the satellite while ensuring the average time delay requirement of the users, and the dynamic balance of the delay and the power consumption can be achieved by adjusting the control parameter.