【摘要】 为了满足6G网络通信下用户接入和高效的资源利用的需求，在无载波幅度相位调制（Carrierless Amplitude-Phase,CAP）方式基础上，引入非正交多址接入（NOMA）技术，提出了一种兼顾功率效率和频谱效率的混合调制方案，即NOMA-CAP混合调制，该方案允许多个用户在有限带宽内以更高的功率效率同时传输更多信息，在保证系统功率效率和频谱效率良好折中的同时，为用户接入提供了更为灵活和高效的选择。给出了NOMA-VLC系统结构模型，推导了NOMA-CAP系统误码性能理论解析式，并通过仿真实验验证了理论推导的准确性。仿真结果表明，在合适功率分配因子条件下，NOMA-CAP系统可以通过灵活的资源配置策略满足不同用户的服务质量需求。更多还原

【Abstract】 In view of the increasing demand for spectrum resources and the demand for multi-connection and multi-access,more and more scholars focus their research on The 6th Generation Mobile Communication Network (6G).It is hoped that 6G technology can fully explore the spectrum resources including millimeter wave,terahertz and optical wireless.Compared with traditional radio frequency technology,Visible Light Communication (VLC) is considered to be one of the key technologies of 6G.VLC uses the commonly used LED light source as the transmitting terminal to transmit information through visible light,so it has rich spectrum resources,high security,and high security.Low cost and other advantages,in the actual promotion and application has a natural advantage.In order to meet the needs of user access and spectrum efficiency in 6G network communication scenario,combining CAP with multiple access technology should be a solution worth studying.On the basis of spectrum efficient Carrierless Amplitude-Phase (CAP) modulation,a NOMA-CAP modulation scheme based on power domain is proposed by introducing non-orthogonal multiple access (NOMA) technology for downlink of VLC system.The scheme adopts power multiplexing technology at the transmitting end.According to the channel conditions of different users,different power is allocated to the CAP-modulated signals of different users in the same frequency band for superposition,and then reaches the receiving end through VLC channel.The successive interference cancellation (SIC) technology is used to eliminate the user signal successively according to the power assigned to the user,so as to realize the correct demodulation of the superimposed signal and effectively distinguish different users.In order to ensure the system power efficiency and spectrum efficiency good compromise at the same time,for the user access to provide more flexible and efficient choice.This paper firstly discusses the NOMA-VLC system structure model.Based on the NOMA two-user model,the theoretical analysis of NOMA-CAP system error performance under additive White Gaussian Noise (AWGN) channel is derived,and the accuracy of the theoretical derivation is verified by simulation experiments.The simulation results show that the bit error rate of NOMA-CAP system increases with the increase of modulation order of two users,and the error performance gap between two users decreases with the increase of modulation order.When two users in the NOMA-CAP system use different modulation schemes,if user 1 uses high-order modulation and user 2 uses low-order modulation,the error performance gap between the two users is much lower than that between the two users using the same modulation.This is because user 2 uses low-order modulation,the noise tolerance becomes larger,and the error performance becomes better.Therefore,in the NOMA-CAP system,the two users can choose the configuration of the modulation order more flexibly according to the system performance requirements.In addition,under the conditions of appropriate power allocation factors,NOMA-CAP system can meet the service quality needs of different users through flexible resource allocation strategies,and the system can also transmit more data on limited spectrum resources,providing an efficient and reliable solution for visible light communication systems.The flexibility of the modulation mode also enables the system to better adapt to different transmission environments and needs.更多还原