在室内可见光通信中，码间干扰和背景噪声极大地限制了系统的传输速率，降低了系统的性能。CDMA多址接入能力强抗干扰性好，OFDM在抗多径效应引起的码间干扰有固有优势。因此，课题拟引入多载波CDMA技术在室内环境下的LED多用户可见光通信中开展研究。首先针对光OFDM调制方法的多样性，对光OFDM调制方法及性能对比研究，结合扩频序列特性，提出一种光O-OFDM-CDMA系统。在此系统下，对因为要得到正实数序列和非理想LED所引起的非线性削波噪声的统计特性和对系统性能影响进行研究；其次，研究降低峰均比来减小削波噪声和LED非线性失真的方法。在此基础上，基于正交互补序列集与准正交序列构造准正交互补序列集，提高系统接入能力和降低多用户干扰。通过理论分析与仿真对提出方案的可行性和优越性进行论证。

In the indoor visible light communication system, the time dispersion of the optical wireless channel setup a major throughput limiting factor for tht systems because of the severe inter-symbol interference at high data rates, and the additive background noise degrades the performance of the system. Code division multiple access (CDMA) is a strong candidate to support multi-users service. A well known modulation technique with an inherent robustness to multipath dispersion is the Orthogonal frequency-division multiplexing (OFDM) transmission scheme. Therefore this work proposes for indoor visible light communication system combines OFDM signals with CDMA multi-user capabilities. Firstly, because of the diversity of optical OFDM, we will research the performance comparison between different methods. So, we will propose the excellent combines the CDMA with optical OFDM. Secondly, in the optical MC-CDMA system the time domain signal envelop is utilized to modulate the LED. For this purpose, the signal needs to be real and non-negative. Thus clipping the signal at zero induces the non-linear noise, and we will study the statistic characteristics and analyses the influencing factor of the system. Then the PAPR reduction techniques are used to degrade the clipping nonlinear noise in optical MC-CDMA. Then the quasi-orthogonal complementary sequences are designed based on the orthogonal complementary sequences and quasi-orthogonal sequences. Finally, we will conduct theoretical analyses and simulation experiments to further support our points.