An exact BER analysis of NOMA-VLC system with imperfect SIC and CSI

Abstract

Visible Light Communication (VLC) has emerged as a promising technology for 5G and beyond networks by offering a wide license free spectrum. In order to develop a high data-rate and error-free network, in this paper, non-orthogonal multiple access (NOMA) technique is combined with VLC technology. In particular, a two user downlink NOMA based VLC system is considered in which the transmitter uses on–off keying (OOK) and L-ary pulse position modulation (L-PPM). The closed form mathematical expressions for bit-error-rate (BER) of OOK and L-PPM modulated NOMA-VLC system is derived in the presence of perfect and imperfect channel state information (CSI). Moreover, imperfect successive interference cancellation (SIC), which is a more practical scenario, is considered for this analysis. The analysis shows that the error performance of L-PPM modulated NOMA-VLC system is superior to OOK modulated NOMA-VLC system for (L > 2). Further, with the far user power allocation coefficient greater than 0.5, the far user completely outperforms the near user. Furthermore, the channel estimation error has an adverse effect on BER performance of the system under consideration. The performance of the considered system is investigated for the parameters of interest, i.e., location of the far user, field of view (FOV) and channel estimation error. The derived analytical BER expressions are verified with the simulation results.