LED可见光通信系统多址干扰消除方法的研究

发布时间：2018-06-16 22:10

本文选题：可见光通信；多址干扰；多用户检测；盲自适应多用户检测 + 　；参考：《西安理工大学》2017年硕士论文

【摘要】：可见光通信(Visible Light Communication,VLC)是利用LED光源进行信息传输的新兴无线通信方式。其具有速率高、无电磁辐射、成本低、频谱丰富、保密性好等特点。多用户VLC系统通常使用单极性码作为地址码,存在严重的多址干扰,限制了系统容量。本文针对这一问题,结合国内外发展现状,对室内多用户LED VLC的多址干扰消除方法进行了深入研究。本文具体完成的主要工作有:1.分析了多址干扰的成因以及不同地址码对LED室内VLC多址干扰的影响。分析了LED光源布局对多址干扰的影响及VLC系统误码率的室内分布情况。提出了光源布局的优化方法,并对优化后光源布局的光照度、接收光功率及误码率进行了仿真分析,验证了优化方法的有效性。2.建立了 OFDM-OCDMA系统模型,分析了静态信道环境下,解相关检测和最小均方误差检测对多址干扰的抑制效果,验证了线性检测器抑制室内VLC系统多址干扰的可行性。3.提出了一种新型变遗忘因子的RLS盲多用户检测算法,推导了自适应遗忘因子的表达形式,仿真分析了该算法对室内VLC系统抑制多址干扰的效果。结果表明,优化光源布局能有效地改善多址干扰及误码率的不均匀分布,提高通信质量;线性多用户检测可有效抑制一般室内多用户VLC系统中的多址干扰和多径干扰;改进型的变遗忘因子的RLS盲多用户检测算法具有收敛速度快的特性。
[Abstract]:Visible Light Communication (VLC) is a new wireless communication mode which uses LED light source to transmit information. It has the characteristics of high speed, no electromagnetic radiation, low cost, rich frequency spectrum and good confidentiality. In multiuser VLC systems, unipolar codes are usually used as address codes, which limit the system capacity due to serious multiple access interference (mai). In order to solve this problem, combined with the development situation at home and abroad, the method of multi-access interference cancellation for indoor multi-user LED VLC is deeply studied in this paper. The main work accomplished in this paper is 1: 1. The causes of multiple access interference and the influence of different address codes on LED indoor VLC multiple access interference are analyzed. The influence of LED light source layout on multiple access interference (mai) and the indoor distribution of bit error rate (BER) of VLC system are analyzed. The optimization method of the light source layout is put forward, and the simulation analysis of the illuminance, the received optical power and the bit error rate of the optimized light source layout is carried out, which verifies the effectiveness of the optimized method. 2. The model of OFDM-OCDMA system is established, and the effectiveness of decorrelation detection and minimum mean square error detection to suppress multiple access interference in static channel environment is analyzed, and the feasibility of linear detector to suppress multiple access interference of indoor VLC system is verified. A new RLS blind multiuser detection algorithm with variable forgetting factor is proposed. The expression of adaptive forgetting factor is derived and the effect of the algorithm on the suppression of multiple access interference in indoor VLC system is simulated and analyzed. The results show that optimizing the light source layout can effectively improve the multiple access interference (mai) and the uneven distribution of the bit error rate (BER) and improve the communication quality, and the linear multiuser detection can effectively suppress the multiple access interference (mai) and the multipath interference (MII) in the general indoor multiuser VLC system. The improved RLS blind multiuser detection algorithm with variable forgetting factor has the characteristics of fast convergence.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.1

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