Energy-Efficient Network Coding Scheme for Two-Way Relay Visible Light Communications

In this paper, we consider a two-way relay (TWR) visible light communication (VLC) system consisting of two users which communicate to each other with the help of a relay. To achieve efficient transmission, we introduce network coding (NC) into VLC system and we develop two energy-efficient NC-based strategies, namely straightforward network coding over finite-alphabet sets (SNCF) scheme and physical-layer network coding over finite-alphabet sets (PNCF) scheme, which need three time slots and two time slots respectively to achieve the communication. Simulation results indicate that our proposed SNCF scheme and PNCF scheme both can achieve great performance gains over the traditional four time-slot transmission scheme.