Error performance of an L-PPM modulated ADR-based MIMO-VLC system with and without channel estimation error.

In recent years, visible light communication (VLC) has emerged as a potential technique for beyond 5G communication networks. In this study, an angular diversity receiver (ADR) is used to propose a multiple-input multiple-output (MIMO) VLC system employing L-pulse position modulation (L-PPM). Repetition coding (RC) is used at the transmitter, while receiver diversity techniques such as maximum-ratio combining (MRC), selection best combining (SBC), and equal gain combining (EGC) are used at the receiver to improve performance. This study presents the exact probability of error expressions for the proposed system with and without channel estimation error (CEE). The analysis shows that the probability of error of the proposed system increases as the estimation error increases. Further, the study shows that the increase in signal-to-noise ratio is not enough to counter the impact of CEE, especially when the estimation error is large. The distribution of error probability of the proposed system using EGC, SBC, and MRC throughout the area of the room is presented. The simulation findings are compared to the analytical results.

NOMA cooperative VLC systems: design and performance analysis with OOK and L-PPM modulation.

Visible light communication (VLC) allows white LEDs to communicate while lighting, which improves resource consumption. Multiple relay approaches can be employed in conjunction with cooperative communications to achieve large gains in spatial diversity, expand the coverage, and possibly boost system capacity. In this paper, the nonorthogonal multiple access (NOMA) cooperative techniques for VLC systems using on-off keying (OOK) and L-pulse-position modulation (L-PPM) are proposed. The maximum ratio combining (MRC) schemes is adopted at the receiving node to combine the signals received from cooperative transmissions. Further, the decode-and-forward relaying protocol is considered for cooperation. The proposed system is analyzed for a multiuser scenario that is followed by a two- and three-user scenario for detailed analysis. This study calculates the bit error probability (BEP) of an OOK/L-PPM modulated NOMA cooperative VLC system under perfect and imperfect successive interference cancellation. Simulation results are presented to validate the produced analytical BEP results.

Error analysis of L-PPM modulated MIMO based multi-user NOMA-VLC system with perfect and imperfect SIC.

By offering a wide license-free spectrum, visible light communication (VLC) has emerged as a game-changing technology for networks beyond 5G. In this study, the multiple-input multiple-output (MIMO) technology is combined with a non-orthogonal multiple access VLC (NOMA-VLC) system to provide a reliable error-free high data rate network for multi-user scenarios. A generalized L-PPM modulated MIMO based multi-user NOMA-VLC system with M×N line-of-sight connections for each user is presented. Considering a practical scenario of imperfect successive interference cancellation, a novel closed form formulation of error probability for the proposed system is obtained. This study also includes a comprehensive analysis of two-user and three-user L-PPM modulated 2×2 MIMO-NOMA-VLC systems, and exact error probability expressions are derived. With the identical set of parameters, the L-PPM modulated MIMO-NOMA-VLC system totally outperforms the on-off keying modulated MIMO-NOMA-VLC system. As the number of photodetectors per user increases, the error probability of the considered system decreases. An L-PPM modulated 2×2 MIMO based three-user NOMA-VLC system offers the best performance at a power allocation co-efficient of 0.3. The simulation results validate the derived error probability expressions.