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Energy Consumption Optimization Study Of Relay UAV Assisted By Intelligent Reflecting Surfaces

Posted on:2024-07-14Degree:MasterType:Thesis
Country:ChinaCandidate:Z Q ChenFull Text:PDF
GTID:2542307100980609Subject:Master of Electronic Information (Professional Degree)
Abstract/Summary:PDF Full Text Request
In recent years,natural disasters have occurred frequently around the world,causing large-scale damage to wireless communication networks in affected areas.In order to reduce losses caused by disasters and timely convey the specific situation of affected areas to the outside world,it is necessary to enable affected areas to receive targeted support from the outside world.Therefore,a temporary and easy-to-deploy mobile relay communication method is needed.Additionally,due to the destruction of energy supply in disaster-affected areas,it is important to ensure that the signal source has sufficient energy to transmit information to the mobile relay.To achieve this,we consider using wireless power transmission technology for the mobile relay to charge the signal source.Thanks to the advantages of easy deployment,strong mobility,and cost-effectiveness,unmanned aerial vehicles(UAVs)can meet these requirements well.However,due to the limited onboard energy of UAVs,the operational range of UAVs is restricted,and the mission time is also limited,which further limits the performance of the system.Therefore,the energy consumption of UAVs in mission execution needs to be highly respected.In recent years,Intelligent Reflecting Surfaces(IRS)have been regarded as important components of future 6G wireless communication technology,and have gradually become a research hotspot.Because a large number of passive reflecting elements are integrated on the IRS,it can intelligently reconstruct the infinite propagation environment,and significantly improve the communication quality.Therefore,we combine UAVs with IRS and apply them in the field of wireless communication to explore the potential advantages by combining the advantages of the two.This will provide corresponding application scenarios for future 6G wireless networks.This thesis first studies a simple scenario of a single intelligent reflecting surface-assisted UAV relay satisfying the minimum information throughput requirements of multiple user groups.The aim is to jointly optimize the trajectory of the UAV,the phase shift of the IRS,and other factors to minimize the energy consumption required for the UAV to complete the task.By using the same direction superposition principle,the phase shift matrix of the IRS under the given UAV trajectory is obtained,thereby achieving phase alignment.Finally,the original non-convex problem is transformed into a convex problem through alternating iterative optimization algorithm and successive convex approximation(SCA)technology,and an approximate optimal solution is obtained.Simulation experimental results show that under the same task completion,the proposed scheme significantly reduces the energy consumption of the UAV compared to the traditional scheme without IRS assistance.Based on the single IRS-assisted UAV communication system studied above,we have extended and deepened it to study a communication system of multiple IRSs jointly assisted UAV based on wireless power transmission(WPT).Under the joint assistance of multiple IRSs,the UAV emits energy signals,and the ground transmitting users collect energy and then forward the information to be transmitted to the UAV,and finally,the UAV forwards all collected information to the corresponding ground receiving users.It is worth noting that we assume that the channel state information is perfect.By jointly optimizing the trajectory of the UAV,the phase shift of the IRS,and time allocation ratio,the total energy consumption of the UAV is minimized.Simulation experimental results show that under the same conditions,the proposed scheme significantly reduces the energy consumption of the UAV compared to the traditional UAV communication system without IRS assistance and the single IRS-assisted UAV communication system.
Keywords/Search Tags:UAV, intelligent reflecting surface, energy optimization, trajectory design, relay
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