TDMA-Like infrared uplink with multi-faces photodiode access points

The Li-Fi paradigm that aims at implementing indoor communications links in indoor scenarios, paid attention to the downlink so as to grant connectivity and illumination to several users in very small cells, also known as attocells. However, few work has been done to face the problem of uplink since the use of visible light that send signals from floor to ceiling can be harmful for human eye. In this work we consider the performance offered by an infrared uplink access essentially based on TDMA. In particular we assume that the access points are characterized by the presence of multiple photodiodes on the ceiling so as to receive the signals coming from different users and directions. In this regard, we explore also the spatial dimension in order to evaluate how many users can access the network with a reasonable level of reliability and without inducing severe interference.