Maximizing constructive interference based on orthogonality and diversity in MISO-VLC systems using FSTD-MRC algorithms

Abstract Spatial diversity in Visible Light Communication (VLC) systems serves as a robust technique for enhancing system performance by utilizing multiple light sources at the transmitter. Meanwhile, the concept of transmitting data orthogonally is employed to facilitate the separation of overlapping optical signals at the photodetector. Therefore, this paper presents a modification for the Frequency Switching Transmit Diversity (FSTD) technique to achieve a higher diversity order while preserving its orthogonality property. As a result of the increased diversity order, Maximal Ratio Combining (MRC) technology is suggested at the receiver to effectively combine received signals; this technique maximizes constructive interference while minimizing the impact of signals degraded by attenuation and obstructions. Additionally, MRC mitigates the effects of unwanted radiation, such as sunlight and ambient light. On this basis, the results demonstrate that the proposed approach achieved a Bit Error Rate (BER) of 3.4×10 −5 at a transmission distance of 40 m with a Signal to Noise Ratio (SNR) of 5 dB. In comparison, the conventional FSTD technique recorded a BER of 1×10 −3 under the same conditions. These findings highlight the superiority of the proposed approach in enhancing the efficiency and reliability of VLC systems, effectively mitigating the impact of optical channel blockages.