Energy-per-bit performance analysis of relay-based visible-light communication systems

Relaying systems, such as amplify-and-forward (AF), decode-and-forward (DF), selective DF (SDF) and incremental DF (IDF) relaying are usually used to ensure high performance and reliability for communication systems. A comprehensive energy efficiency performance study for different half-duplex relaying protocols, namely DF, SDF and IDF over visible light communication (VLC) channels is provided in this paper. Accurate analytical expressions for both outage probability and the minimum energy-per-bit performance of the aforementioned relaying systems are derived. For the sake of comparison and to justify the use of relays in the proposed system, the performance of a single-hop scenario is analyzed and compared to the relay-based links. The accuracy of the analysis is verified by Monte Carlo simulations. The results reveal that the single-hop VLC system offers the poorest performance compared to that offered by VLC relay-based systems particularly for relatively high end-to-end distances. However, the best performance is offered by SDF and IDF schemes as they have a lower outage probability than other systems under consideration. This work also shows that the performance of the systems under consideration is affected by some parameters, such as the vertical distance to user plane and the maximum cell radius of the LED.