Path Selection for Relay-Assisted Underwater Visible Light Communication Systems

In this paper, we consider underwater visible light communication (UVLC) system with M parallel relaying paths where each path has N decode-and-forward (DF) relays. One path (not necessarily the best one) out of M paths is selected for transmission. Such a multi-hop system is especially useful since some relay nodes might break down or malfunction and hence single path might not be sufficient. Furthermore, selection of the best path is not always possible due to several reasons such as the effect of noise on the estimation of the best path and feedback error. Under the assumption of lognormal (LN) turbulence channels, we derive a closed-form expression for the outage probability of UVLC system where the $m^{\mathrm{th}}$ best path is selected for transmission. We then use our derived closed-form outage probability for investigating the so-called incremental diversity order (IDO).