A comprehensive study on indoor VLC systems using advanced equalization techniques employing CAP modulation in SISO, SMP, and SM configurations

IF 3.3 Q3 Physics and Astronomy

Results in Optics Pub Date : 2026-03-01 Epub Date: 2026-05-11 DOI:10.1016/j.rio.2026.101033

Saeed Ashouri, Gholamreza Baghersalimi, Hossein Goorani

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引用次数: 0

Abstract

Indoor visible light communication (VLC) using light-emitting diodes (LEDs) faces critical performance challenges due to LED nonlinearity, limited modulation bandwidth, and multipath-induced inter-symbol interference. This study evaluates carrierless amplitude and phase (CAP) modulation across single-input single-output (SISO), spatial multiplexing (SMP), and spatial modulation (SM) configurations, employing linear least mean square (LMS) and nonlinear Legendre functional link artificial neural network (Le-FLANN) and Volterra equalization techniques. Under realistic LED operating conditions and spatial misalignment, Le-FLANN achieves significant signal-to-noise-ratio per bit (E_b/N₀) improvements at bit error rate (BER) = 10⁻⁴: 0.9 dB in SISO, 2.9 dB in SMP, and 1.5 dB in SM, compared to LMS. SMP delivers an aggregate throughput of 24 Mbps by transmitting two independent 12 Mbps CAP streams in parallel over a 4.5 MHz LED bandwidth. These findings demonstrate the practical value of structured nonlinear equalization in bandwidth-constrained VLC links, offering enhanced resilience to LED-induced distortion and spatial channel impairments.

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在SISO、SMP和SM配置中采用CAP调制的先进均衡技术，对室内VLC系统进行了全面研究

使用发光二极管（LED）的室内可见光通信（VLC）由于LED的非线性、有限的调制带宽和多径诱导的符号间干扰而面临着关键的性能挑战。本研究采用线性最小均方（LMS）、非线性勒让德函数链人工神经网络（Le-FLANN）和Volterra均衡技术，评估了单输入单输出（SISO）、空间复用（SMP）和空间调制（SM）配置下的无载波振幅和相位（CAP）调制。在实际LED工作条件和空间失调情况下，与LMS相比，Le-FLANN在误码率(BER) = 10−4时实现了显著的每比特信噪比（Eb/N0）改善：SISO为0.9 dB， SMP为2.9 dB， SM为1.5 dB。SMP通过在4.5 MHz LED带宽上并行传输两个独立的12 Mbps CAP流，提供24 Mbps的总吞吐量。这些发现证明了结构非线性均衡在带宽受限的VLC链路中的实用价值，可以增强对led引起的失真和空间信道损伤的弹性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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