Zhang Lu, Wang Han, Zhao Xu, Lu Fang, Zhao Xiaoming, Shao Xiaopeng
Opt Express. 2019 Mar 4;27(5):6672-6688. doi: 10.1364/OE.27.006672.
In this paper, a two-path parallel scheme for m-QAM-OFDM transmission in optical wireless communications was proposed, and its principle was theoretically derived. This scheme transmitted two-path parallel OFDM signals, which carried m-QAM mapped data symbols and their conjugated data symbols respectively. Simple superimposition at the receiver was performed to mitigate the inter-carrier interference (ICI). The feasibility of the scheme was experimentally demonstrated over a turbulent-air-water channel. The results show that the proposed scheme was not sensitive to time delay between the two paths, and it brought significant improvement of bit error rates (BER) performance compared to conventional single-path m-QAM-OFDM transmission scheme even in the turbulent-air-water channel. The proposed scheme has great potential in free space optical (FSO) communications, visible light communications (VLC) and underwater optical wireless communications (UOWC).
本文提出了一种用于光无线通信中m-QAM-OFDM传输的双路径并行方案，并从理论上推导了其原理。该方案传输双路径并行OFDM信号，它们分别携带m-QAM映射数据符号及其共轭数据符号。在接收机处进行简单叠加以减轻载波间干扰（ICI）。该方案的可行性在湍流空气-水信道上通过实验得到了验证。结果表明，所提出的方案对两条路径之间的时间延迟不敏感，并且即使在湍流空气-水信道中，与传统的单路径m-QAM-OFDM传输方案相比，它在误码率（BER）性能方面也有显著提高。所提出的方案在自由空间光（FSO）通信、可见光通信（VLC）和水下光无线通信（UOWC）中具有巨大潜力。
