Dynamic Frequency Reuse Based on Improved Tabu Search in Multi-User Visible Light Communication Networks

The visible light communication (VLC) system using light-emitting diodes (LEDs) is able to achieve a higher transmission rate compared with the traditional radio frequency network. However, the throughput and average spectral efficiency (ASE) of the system may decrease due to the inter-cell interference and the inter-user interference, particularly for the indoor environment, where the LEDs are densely deployed in the case of multiple users. To suppress such interference, we introduce innovatively the improved tabu search (TS) algorithm into the frequency reuse in the multi-user VLC networks. We propose a bidirectional double tabu list strategy to avoid getting trapped in the situation of the local optimum. In addition, we design the evaluation function and aspiration criterion of the algorithm. We employ the improved TS algorithm to find the optical dynamic frequency reuse scheme by combining the interference graph. The interference graph is used to determine the interference relationships and to construct the solutions to the algorithm. The simulation results show that our proposed scheme effectively improves the throughput and the ASE of the system without lowering the fairness performance, especially in the scenario of numerous users.