BER analysis of dynamic FOV based MIMO-NOMA-VLC system

Visible Light Communication (VLC) has evolved as a breakthrough technology for beyond 5G networks by providing a wide license-free spectrum. In this paper, we build a robust NOMA-VLC Network which exploits the MIMO technique. In particular, a two-user 2 x 2 MIMO-NOMA-VLC system is proposed which considers on-off keying (OOK) modulation and L-pulse position modulation (L-PPM). The closed-form bit-error-rate (BER) expressions for the OOK and L-PPM modulated two-user MIMO based NOMA-VLC system are derived with the consideration of perfect and imperfect successive interference cancellation (SIC). The analysis shows that the proposed system marginally outperforms the single-input single-output SISO-NOMA-VLC system. The error performance of L-PPM modulated system is superior to that of OOK modulated system for L > 2. Further, the increment in the number of photo detector (PD's) at the receiver does not improve the error performance of the system significantly. To address this, two dynamic field of view (FOV) strategies are proposed for attaining the additional enhancement in error performance of OOK and L-PPM modulated MIMO-NOMA-VLC system. The 2 x 2 MIMO-NOMA-VLC system based on dynamic FOV strategy-2 completely outperforms the 2 x 2 MIMO-NOMA-VLC systems based on static FOV and strategy-1 in terms of error performance. The effect of power allocation coefficient, alpha, on the error performance of the proposed systems is investigated. The best average error probability of a two-user MIMO-NOMA-VLC system is attained at alpha = 0.3. The simulation results are in close alignment with those of the analytical outcomes.