Research On Power Allocation Scheme For Indoor VLC System Based On NOMA

With the development of new mobile service,the demand of various applications of wireless network is explosive,so it is necessary to upgrade the existing commercial network.Compared with the traditional RF communication,visible light has rich spectrum resource.So visible light communication(VLC)emerges as the times require.As a new communication technology,it is easy to obtain the optical signal in a VLC system,which also has a fundamental function of illumination.VLC has the advantages of simple signal source acquisition,lighting function,low cost,no spectrum authentication,no electromagnetic interference and high transmission rate.In order to further improve the spectrum utilization and the total system rate,many researchers propose to introduce non orthogonal multiple access(NOMA)technology into the indoor VLC system to improve the total throughput of the system.For the indoor VLC system based on NOMA,the power allocation scheme greatly affects the system’s total data rate,user fairness and other performance indicators.So the power allocation scheme has become a research hotspot of NOMA-VLC,this paper studies the power allocation scheme in indoor NOMA-VLC.Firstly,this paper introduces the background,significance and present situation of NOMAVLC,then mainly expounds the theoretical basis of NOMA,deeply analyzes the basic principles and key technologies of various NOMA technologies,and focuses on the basic principles and key technologies of power domain non-orthogonal multiple access technology.Indoor NOMA-VLC system is often affected by the actual environment.At the same time,the successive interference cancellation(SIC)algorithm is complex,which leads to two problems in the system: one is that the transmitter can’t obtain the perfect channel state information(CSI),the other is that the SIC can’t decode the user’s useful information perfectly.In response to the above problems,this paper establishes an Imp(Imperfect)NOMA-VLC system model.,then studies the power allocation scheme based on IMP NOMA-VLC.Finally analyzes the feasibility and superiority of this model through simulation.Last but not least,an IMP NOMA-VLC system power allocation scheme based on improved particle swarm algorithm is proposed.Due to the defects of standard particle swarm optimization,such as easy to fall into local optimum and premature convergence,this paper improves the selection of inertia weight,individual learning factor and social learning factor of standard particle swarm optimization.Aiming at the IMP NOMA-VLC system,the improved particle swarm algorithm is adopted to solve the power distribution scheme.The simulation results show that compared with the power allocation scheme based on standard particle swarm optimization,the power allocation scheme based on the improved particle swarm optimization has obvious improvement in convergence speed,iteration times and total data rate.