Research On User Access Algorithm In UAV-Assisted Wireless Networks

Unmanned aerial vehicle(UAV)can be deployed on demand due to its high mobility and flexibility.Moreover,the high line-of-sight probability characteristics of its air-to-ground channel also provide a guarantee for high-quality aerial services.Therefore,UAV can be used as aerial base stations to deploy on-demand in wireless networks and improve network coverage.However,in the UAV-assisted wireless network,the traditional user access strategy still leads to problems and challenges such as unbalanced load among base stations,low network throughput,and high energy consumption of base stations.To this end,this thesis conducts research on user access algorithms,the main contents are as follows:Firstly,in the downlink scenario of UAV-assisted wireless network,in order to solve the problem of imbalanced load among UAV base stations,a load balancing access algorithm based on utility function is proposed.The algorithm maximizes the utility function by jointly optimizing user access and UAV base station placements,thereby achieving load balancing among UAV base stations.Secondly,in the downlink scenario of UAV-assisted wireless network,in order to improve the throughput of the network,a dual-layer iterative access algorithm based on alternating optimization is proposed.User access and UAV base station placements are jointly optimized to maximize the throughput of users served by the UAV base stations.Simulation results show that the proposed algorithm significantly improves the throughput of users.Finally,in the scenario where UAV acts as an aerial base station to assist ground base station(GBS)to provide services,in order to reduce the communication energy consumption of the base stations,The transmission rate contribution weight provided by the base stations to the user and power allocation are jointly optimized to minimize the communication energy consumption of the base stations.The simulation results show that the proposed algorithm significantly reduces the communication energy consumption of the base stations.