基于非正交多址接入的星间可见光通信最优功率分配研究  

Optimal Power Allocation for Intersatellite Visible Light Communication Based on Nonorthogonal Multiple Access

作　　者：郝少伟 李勇军[1] 赵尚弘[1] 宋鑫康 Hao Shaowei;Li Yongjun;Zhao Shanghong;Song Xinkang(Institute of Information and Navigation,Air Force Engineering University,Xi'an,Shaanxi 710077,China)

机构地区：[1]空军工程大学信息与导航学院,陕西西安710077

出　　处：《中国激光》2021年第7期119-128,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(91638101);陕西省自然科学基金(2018JM6069)。

摘　　要：星间可见光通信(VLC)凭借其优势逐渐成为小卫星领域的研究热点。通过功率复用,非正交多址接入(NOMA)技术可有效解决因LED调制带宽较窄而导致的VLC系统容量和通信速率受限的问题。结合星间VLC和NOMA技术,构建了星间NOMA-VLC系统,并对信道模型和噪声模型进行了分析。针对系统通信速率优化问题,建立了基于和速率(Sum-Rate)最大化的优化模型,在将非凸的目标函数转换成凸函数的基础上,通过凸分析给出了目标问题的显式最优解。仿真结果表明,和已有功率分配算法相比,所提功率分配策略在保证最低数据速率的约束下,可显著提升系统的和速率。Objective With the continuous development of small satellite technology,a large number of small satellite groups flying in formation have gradually replaced single large satellites and become a research hotspot in the field of aerospace.However,due to the constraints of size,mass,and power consumption of small satellite platforms,traditional RF and laser communication technologies can no longer meet the demand of large-capacity,small-delay,and high-reliability intersatellite communication links.As one of the most promising key technologies for the fifth wireless communication and beyond,visible light communication(VLC)has great potential in improving the spectrum efficiency and reducing the cost of spacecraft with many license-free spectrum resources.In practical applications,the narrow modulation bandwidth of LED seriously limits the system capacity and VLC communication rate.Thus,many high spectral efficiency technologies are used to improve the VLC system's data rate,including adaptive modulation,equalization technology,multiple input multiple output(MIMO),and multiple access technology.Among them,power domain NOMA(PD-NOMA)is suitable for downlink VLC systems to enhance the capacity and communication rate through power multiplexing.Methods In this study,by combining the intersatellite VLC and NOMA technology,an intersatellite NOMA-VLC system consisting of a three-star formation configuration is constructed.Then,based on the analysis of the line of sight(LOS)link model of intersatellite and noise model at the receiver side,the model of signal transmission with power multiplexing is developed.Aiming at the problem of system communication rate optimization,an optimization model based on sum-rate maximization for the system is established.By transforming the nonconvex objective function into the convex function,an optimal power allocation strategy with low complexity is proposed to exploit the explicit optimal solution to the target problem using convex analysis.Results and Discussions The performance of the NOMA

关 键 词：光通信 可见光通信 星间通信 非正交多址接入 功率分配 

分 类 号：TN929.12[电子电信—通信与信息系统]