Joint NOMA Transmission in Indoor Multi-cell VLC Networks

In this paper, we consider downlink multiuser communication in indoor visible light communication (VLC) networks with multiple attocells using non-orthogonal multiple access (NOMA) transmission. We propose a joint NOMA transmission scheme, where the users in multi-cell overlapping regions are jointly served by all the corresponding VLC access points. For the proposed scheme, we consider efficient subcarrier allocation techniques, namely, area based subcarrier allocation and user based subcarrier allocation. Our performance results show that the proposed joint transmission scheme achieves significantly higher sum rates compared to the frequency reuse factor-2 (FR-2) NOMA scheme which uses independent transmission across multiple attocells. In particular, the area based subcarrier allocation scheme performs better than FR-2 NOMA for large number of users and the user based subcarrier allocation scheme performs better than FR-2 NOMA for any number of users.