Interference Suppression for VLC System Based on Optimized Channel Detection Algorithm

In Visible Light Communication (VLC) systems, multipath effects significantly challenge achieving high-quality communication and optimal system performance. The paper introduces the Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) technique within an indoor VLC system and presents an optimized channel detection method. The optimized algorithm, based on the Tomlinson-Harashima Precoding (THP) method, utilizes multi-user channel information to decompose the relevant channel matrix. The Bit Error Rate (BER) of the optimized algorithm is systematically evaluated under different interference environments, the number of users and transceiver configurations. In addition, the BER performance, Weighted Sum Rate (WSR) performance, and diversity gain of the improved algorithm and other commonly used algorithms are investigated. The simulation results show that the system using this scheme has the advantages of a large capacity, high transmission rate, and good anti-interference ability. The optimization algorithm achieves a BER of less than 10⁻⁴ at a signal-to-noise ratio (SNR) of 20 dB. Compared to conventional detection algorithms such as Minimum Mean Square Error (MMSE), Block Diagonalization (BD), and standard THP, the proposed method improves BER performance by up to one order of magnitude and enhances the WSR by 15%–25% in multi-user scenarios. These results demonstrate the superior interference suppression capability and scalability of the proposed scheme in VLC systems.