Research On Physical-Layer Network Coding Resource Allocation Method For Uav Relay Communication

With the application of 5G,Unmanned Aerial Vehicles(UAV)technology has rapidly developed and become a research hotspot in 5G cellular networks.When the deployment and operation of the UAV is appropriate,it can provide reliable and costeffective wireless communication solutions for various practical scenarios.Compared with traditional base stations or relays,UAV can effectively avoid obstacles and provide line-of-sight communication links with ground users,so as to effectively expand the coverage of communications.Because the UAV has the characteristics of flexibility in space and wide access range,its communication efficiency and resource utilization rate need to be used more effectively,so it is considered to introduce physical-layer network coding into UAV relay communication to improve its transmission efficiency.This paper intimately combines the actual application scenarios of UAV relay communication networks,where we constructs two different topological structures of UAV relay communication system models based on physicallayer network coding and then mathematical modeling and analysis it.By modeling the optimization problem and using the convex optimization algorithm to find the optimal solution,an alternating joint optimization algorithm of UAV trajectory and power distribution is proposed to solve the original non-convex problem.Simulation results show that the proposed optimization algorithm can effectively reduce communication The probability of system outage improves system performance.The main research contents of this article are as follows:First,a theoretical analysis of the UAV relay communication system that introduces physical-layer network coding is carried out.The advantages and main problems of the combination of physical-layer network coding and UAV relay communication network are analyzed.The communication model is modified to be more practical for the application of physical-layer network coding.Secondly,the UAV relay communication model under the symmetric topology is established.Mathematical modeling and optimization of the model are established,and an alternate joint optimization algorithm is proposed to complete the joint optimization of the UAV trajectory and power distribution.In the trajectory optimization algorithm,KKT conditions and Lagrangian duality are used,and the method of derivation and verification of extreme points is used for power distribution.Simulation results show that using this algorithm can effectively reduce the probability of system communication interruption and improve the performance of the communication system.Finally,the UAV relay communication model under asymmetric topology is established.Mathematical modeling and optimization problems are established for the model,which is closer to the reality than the symmetric topology,because most communication scenarios are asymmetric.An alternate joint optimization algorithm is proposed to complete the joint optimization of the UAV trajectory and power distribution.The KKT condition and Lagrange duality are used in the trajectory optimization algorithm.The power distribution algorithm uses the interior point method to solve the suboptimal solution.Simulation results show that this algorithm can effectively reduce the probability of system communication interruption and improve the performance of the communication system under an asymmetric structure.