Research on Joint Optimization Algorithm for Resource Allocation in Non-orthogonal Multiple Access Visible Light Communication

In order to satisfy the large-scale access of visible light communication (VLC) users as well as the demand of user request rate, the resource allocation problem of VLC with non-orthogonal multiple access (NOMA) technique is investigated, aiming to improve the average user data rate of the system. An effective scheme for joint optimization of user grouping, power allocation and access point (AP) location is proposed. According to the state of user channel information, a packet strategy with channel gain difference for any number of users is designed. The objective function for maximizing the average user data rate with constraints is constructed, and for this non-convex NP-hard problem, the optimization problem with constraints is transformed into an optimization problem without constraints by introducing the idea of penalty function. This is then solved by the Harris Hawk Optimization (HHO) algorithm based on the nonlinear energy convergence factor to finally find the optimal user power allocation factor as well as the location of the AP. Simulation results show that the proposed joint optimization algorithm can better improve the average user data rate compared with other classical algorithms, which verifies that the HHO algorithm based on the nonlinear energy convergence factor has faster convergence speed and higher solution accuracy compared with the classical HHO algorithm.