Research On Power Allocation Algorithm In UAV Relay Communication System

Due to the good maneuverability and simple deployment of unmanned aerial vehicles(UAV),wireless relay communication using UAV node has received much attentions.As an important resource of UAV relay communication system,the power allocation has great effects on the performance of each link.Optimal power allocation can improve the performance of total system dramatically.Therefore,in this paper,we will study the power allocation of UAV relay communication system by the optimal energy efficiency rule.The main contributions are as follows:(1)A power allocation algorithm of dual UAV relay communication system is studyed.First,a theoretical optimization model for power allocation is established and transforms the power allocation problem into an optimization problem by solving the maximum system energy efficiency.For optimization solution,with the fixed transmitted signal power,an optimized beamforming scheme is obtained first.Then,through the large signal-to-noise ratio interval approximation,the problem of non-convex optimization is transformed into the convex optimization solution.Finally,using the Karush-Kuhn-Tucker(KKT)condition,the closed form expression of the optimal power allocation is obtained.Simulation results show that the proposed algorithm can achieve higher system energy efficiency than the average power allocation algorithm.(2)A power allocation algorithm for UAV multi-hop relay communication system is studyed.Firstly,the energy efficiency expression of multi-hop relay communication system is studied,and a mathematical optimization model for power allocation is established.For optimization solution,the intelligent optimization method is utilized and the optimal power allocation is obtained.Simulation results show that the number of relays has a great impact on the energy efficiency of the system.As the number of relays increases,the energy efficiency of the system decreases.(3)A power allocation algorithm for UAV cooperative communication system is studyed.After the energy efficiency expression of the target node under cooperative communication is studied,an optimization model for power allocation is established by maximum system energy efficiency.Then,the particle swarm algorithm is used to solve the above mathematical model and obtain the optimal power allocation result.Finally,Simulation results show the effectiveness of the proposed algorithm.