Resource-Allocation Strategy for VLC/RF Systems

To address the problem of resource-allocation strategies that limit the system transmission rate in visible light communication and radio frequency (VLC/RF) systems, a new resource-allocation method is proposed and orthogonal frequency-division multiple-access (OFDMA) technology is introduced. Thus, the capacity of the communication system is effectively increased. In the VLC/RF system model based on OFDMA, the Lyapunov optimization method is used to transform the time-averaging problem into a series of single-slot online problems. To reduce its computational complexity, the optimization problem is decomposed into three independent subproblems. The Lagrange relaxation method and convex-optimization theory are used to solve the subproblems to maximize the average system transmission rate. The Lyapunov drift is used to ensure the stability of the system. The simulation verified that the Lyapunov optimization algorithm does not require iterations, which greatly improves the optimization speed. In addition, the simulation results show that using OFDMA technology in the indoor VLC/RF system effectively improves the system capacity, while solving the optimization problem. The proposed resource-allocation strategy effectively balances the system queue length and transmission rate, and maximizes the average system transmission rate while ensuring system stability. The Lyapunov optimization algorithm is comparable to other algorithms in terms of system stability and transmission rate, thereby proving its effectiveness.