Performance-enhanced NOMA-VLC using subcarrier pairwise coding

Abstract

To alleviate the error propagation issue of non-orthogonal multiple access (NOMA) based visible light communication (VLC) systems, we propose and experimentally demonstrate the subcarrier pairwise coding (PWC) based NOMA-VLC. Without extra coding overhead, the computation-efficient subcarrier PWC can significantly improve the overall system performance by pairing the subcarriers of high signal-to-noise ratios (SNRs) with those of low SNRs. Under different transmitted baud rate from 150 MSa/s to 225 MSa/s, the bit error rate (BER) performance with and without PWC is investigated in a NOMA-VLC system. Experimental results show that with the optimized power ratio between the NOMA users, up to 3.3-dB Q 2-factor improvement can be achieved by the proposed scheme.

Performance analysis of a low-complexity nonorthogonal multiple access scheme in visible light communication downlinks using pulse modulations

“…The above investigations show that most EP mitigation approaches in NOMA-VLC systems are designed for QAM [36,37] or OFDM [38] . Given that VLC prefers Intensity Modulation and Direct Detection (IM/DD), pulse modulation schemes, such as OOK, pulse position modulation, and pulse width modulation, attract considerable attention and are widely implemented in VLC systems because of its low cost and simplicity [40,41] .…”

“…In Ref. [38], Shi et al proposed the subcarrier pairwise coding scheme in NOMA-VLC systems with OFDM adopted. This scheme was experimentally demonstrated, and the corresponding results showed that the system performance can be remarkably improved.…”

Demonstration of Non-Hermitian Symmetry (NHS) IFFT/FFT Size Efficient OFDM Non-Orthogonal Multiple Access (NOMA) for Visible Light Communication

“…In 2019, C. Chen et al reported a SIC-free NOMA-VLC using constellation partitioning coding with transmission distance of 100 cm and UE offset of 10 cm [16]. J. Shi et al demonstrated a NOMA-VLC using subcarrier pair-wise coding with transmission distance of 40 cm [17]. In the same year, H. Li et al illustrated a NOMA-VLC using pre-distorted layered asymmetrically clipped OFDM with transmission distances of 40 cm and 70 cm for UE 1 and UE 2 respectively [18].…”