可见光通信中多通道SiPM的分数延迟与时序对齐方法

Fractional Delay and Timing Alignment Method for Multi-Channel SiPMs in Visible Light Communication

摘要:

硅光电倍增管（SiPM）可提升可见光通信（VLC）系统接收灵敏度，但在高光子通量下受微单元数量与死区时间限制，易引入非线性失真，导致系统误码率上升和动态范围受限。为抑制该失真，本文提出一种用于SiPM接收端的多通道分数延迟与时序对齐方法。将入射光均匀分配至多路并行通道，各通道前端配置有限脉冲响应（FIR）分数延迟器；信号经SiPM光电转换后，在接收端采用与前端相互补的反向分数延迟滤波器完成时序对齐，并以等增益合并实现线性合成。合成后的信号用于后续均衡与解调。仿真结果表明，相较于无延迟的并行架构，所提的方法能有效抑制非线性失真，在SiPM近饱和区显著改善误码率；在目标误码率下，针对6通道系统，动态范围提升约6.6dB。

Abstract:

Silicon photomultipliers (SiPMs) can enhance the reception sensitivity of visible light communication (VLC) systems. However, under high photon flux, the finite number of microcells and their recovery time impose constraints, leading to nonlinear distortion, increased bit error rate (BER), and limited dynamic range. To mitigate this distortion, this paper proposes a multi-channel fractional delay and timing alignment method for SiPM receivers. The incident optical signal is evenly distributed across multiple parallel channels, each equipped with a finite impulse response (FIR) fractional delay filter at the front end. After optical-to-electrical conversion by the SiPM, complementary inverse fractional delay filters are applied at the receiver to achieve temporal alignment, followed by equal-gain combining for linear signal synthesis. The combined signal is then processed for subsequent equalization and demodulation. Simulation results demonstrate that, compared with a parallel architecture without delay, the proposed method effectively suppresses nonlinear distortion and significantly improves BER performance in the near-saturation region of the SiPM. For a six-channel system, the dynamic range is improved by approximately 6.6 dB at the target BER.