In this paper, we propose a novel method to generate real signal for Visible Light Communication (VLC) systems without using traditional hermitian symmetry on the data symbols obtained using M-ary Pulse Amplitude Modulation (PAM) which is named as Auxiliary PAM (Ax-PAM). We mathematically analyse this method to generate a real signal with tunable energy using auxiliary symbols at the transmitter and the corresponding receiver. Simulation results for Bit Error Rate (BER) show better performance over conventional PAM Discrete Multi-Tone (PAM-DMT) and Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACO-OFDM) even under clipping distortion and also demonstrate the tunable energy for the proposed scheme. Furthermore, the proposed scheme is implemented on a VLC test bed designed using Universal Software defined Radio Peripheral (USRP). The experimental results for estimated Signal to Noise Ratio (SNR) and achieved BER for Ax-PAM outperforms PAM-DMT and ACO-OFDM.

中文翻译：

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用于强度调制和直接检测系统的可调能量信号：理论、模拟和实验

在本文中，我们提出了一种为可见光通信 (VLC) 系统生成真实信号的新方法，而无需对使用多进制脉冲幅度调制 (PAM) 获得的数据符号使用传统的厄密对称性，该数据符号称为辅助 PAM (Ax- PAM）。我们对这种方法进行数学分析，以使用发射器和相应接收器处的辅助符号生成具有可调能量的真实信号。误码率 (BER) 的仿真结果显示出优于传统 PAM 离散多音 (PAM-DMT) 和非对称限幅光正交频分复用 (ACO-OFDM) 的性能，即使在限幅失真情况下，也证明了所提出的可调谐能量方案。此外，提议的方案在使用通用软件定义无线电外设 (USRP) 设计的 VLC 测试台上实施。Ax-PAM 的估计信噪比 (SNR) 和实现的 BER 的实验结果优于 PAM-DMT 和 ACO-OFDM。