A Tractable Approach to Joint Transmission in Multiuser Visible Light Communication Networks

In this paper, an analytical model for the coverage analysis of multiuser visible light communication (VLC) networks is presented, taking into account the cooperation among access points (APs). Specifically, the cooperation is realized through joint transmission (JT), where the coordinated APs jointly transmit data to users in a noncoherent or coherent manner to reduce the inter-cell interference and enhance the useful signal power. Using a second-order moment matching approach, we find approximate distribution functions of the signal power and interference, and derive tractable results for the network coverage probability based on the signal-to-interference-plus-noise ratio (SINR). For both noncoherent and coherent JT, the derived coverage probabiklity are further simplified into closed forms when the communication link is interference-limited. We validate the derived results through Monte Carlo simulations and apply them to study behaviors and trends of the network under various parameter settings. Results show that JT can improve the coverage performance of the network and coherent JT can provide higher performance gains than its noncoherent counterpart, at the cost of higher implementation complexities.