Performance optimization of hybrid VLC-PLC systems using OFDM-QAM modulation for High-Speed indoor communications

This paper proposes a novel hybrid Visible Light Communication (VLC) and Power Line Communication (PLC) framework, optimized through Orthogonal Frequency Division Multiplexing with Quadrature Amplitude Modulation (OFDM-QAM), aiming to enhance spectral efficiency, reliability, and power efficiency in high-speed indoor networks. The proposed architecture exploits the complementary strengths of VLC’s high-capacity optical wireless access and PLC’s cost-efficient wired backbone, providing seamless broadband connectivity in indoor environments. A comprehensive MATLAB-based simulation framework was developed to analyze Bit Error Rate (BER), Error Vector Magnitude (EVM), and Peak-to-Average Power Ratio (PAPR) under varying modulation orders, subcarrier allocations, and channel conditions. Numerical results demonstrate that for a 128-subcarrier OFDM system with 4-QAM, the proposed design achieves a BER of 1.2 × 10 -5 at 20 dB E b / N 0 , compared to 4.7 × 10 -4 for 16-QAM under the same conditions—representing an almost 39 × improvement. Simulation results confirm that the proposed hybrid configuration achieves an EVM of 3.8 %, corresponding to a 52 % relative reduction versus the standalone PLC case with 8.0 %. Additionally, the proposed hybrid scheme yields a 22 % relative EVM improvement (from 4.1 % to 3.2 %) compared to a state-of-the-art predistortion method. A concurrent 18 % PAPR reduction over standalone OFDM is also demonstrated. In comparison to state-of-the-art VLC-RF and PLC-VLC hybrids, the proposed design achieves nearly an order-of-magnitude enhancement in reliability, while maintaining spectral efficiency. These findings establish the hybrid VLC-PLC architecture as a promising candidate for next-generation indoor broadband networks.