Research On Optical Power Coverage Optimization For UAV-enabled Visible Light Communication

Visible light communication(VLC)based on unmanned aerial vehicles(UAVs)can simultaneously transmit data and lighting.Therefore,UAV-enabled VLC has been considered as a promising technology and has wide applicability in various communication scenarios.This paper studies the received optical power coverage problem of UAV-enabled VLC communication.According to the channel model of UAV-enabled VLC communication system,two different optimization problems are established and different algorithms are proposed to solve them.First,in the UAV-enabled VLC network system,the positions of the UAVs affect the communication angle and distance between the signal source and the receiving point,thereby affecting the channel gain.In addition,the transmission power of the UAVs directly has direct effects on the strength of the received optical signal.Therefore,this paper solves different optical power coverage optimization problems by jointly considering the positions and the transmission power adjustment factors of UAVs.Secondly,the first optimization problem is to ensure the uniformity of optical power coverage on the receiving surface.It is suitable for the scenario where the distribution density of users is high and they can move freely.Uneven optical power coverage will lead to high optical signals in some corners,while the optical signal strength in some corners may be insufficient,which seriously affects communication quality and user experience.In order to ensure that all corners can communicate normally,it is necessary to provide consistent and uniform optical power distribution.Therefore,this paper formulates the uniform optical power distribution problem.In addition,an improved cuckoo search algorithm(ICSCM)is proposed to solve the problem of uniform optical power distribution.ICSCM introduces the chaotic solution initialization operation,mutation operator of differential evolution(DE)algorithm and Gaussian perturbation to make it further jump out of the local optimal solution.Simulations are conducted to analyze the optical power distribution under different numbers of UAVs and to prove that ICSCM can effectively solve this problem.Finally,the second optimization problem is to concentrate on the optical power to cover the safe area in the area.Using the method of combining beamforming with visible light communication,the optical signal emitted is concentrated in the safe area,and the received signal strength in the unsafe area is far lower than that in the safe area.At the same time,it provides uniform optical power to the safe area to ensure that legal receivers can smoothly access the network.Therefore,this paper formulates the security optical power distribution problem,and this problem is a multi-objective optimization problem.On the other hand,this paper proposes an improved non-dominated sorting genetic algorithm Ⅲ(INSGA-Ⅲ)to solve this multi-objective problem.INSGA-Ⅲ uses mutation operator of grey wolf optimizer(GWO)and adaptive mutation operator to improve the search efficiency of the algorithm,under that the algorithm can generate better solutions.Simulations are conducted to prove that INSGA-Ⅲ can get the safe optical power distribution.In conclusion,this paper constructs two received optical power coverage optimization problems for the optical power distribution requirements in the two scenarios,and uses different algorithms to optimize the position of the UAV and the transmit power adjustment factor to solve the problem,and finally analyze the effect according to the simulation experiment.