基于MIMO-OFDM可见光通信系统降低PAPR算法研究
发布时间：2018-11-22 17:34
【摘要】：LED可以在满足照明的同时实现高速通信,具有通信速度快、安全、抗电磁干扰等特点,具有广泛应用前景。但由于照明需要,采用多个LED阵列作为信号发射源,造成多径效应,降低通信质量。为此抗多径能力较强、多信号源同时传输的MIMO-OFDM调制方法得到应用。然而MIMO-OFDM中信号由多个子信道信号组成,随着信号中同向成为的叠加,必然会引起较高的PAPR(峰均值比)。实验表明,较高的峰均功率比会造成信号在通过相关器件时的非线性失真。因此,降低均峰值比成为提高基于MIMO-OFDM的可见光通信系统质量的重要途径。目前降低峰均值比的方法可以分为三大类：概率类、信号预畸变类以及编码类。其中,概率类算法能够在不增加误码率的条件之下降低系统的PAPR,但是这类算法计算量加大并且降低PAPR效果不是很明显；信号预畸变类算法结构简单、效果明显,但是会增加系统的误码率。本文从前两类算法出发,充分均衡了计算复杂度、降低PAPR效果以及引入误差三方面的关系,提出了一种联合使用概率类算法中的部分传输序列(PTS)以及信号预畸变类算法中的压扩(Companding)的算法—-PTS-Companding算法来降低系统的PAPR。通过研究信号自相关性与峰均值比的关系,叠加自相关性较低的训练序列来进一步降低系统的PAPRo理论分析和MATLAB仿真表明,改进算法的计算复杂度以及引入误差与PTS-Companding算法相当,但是PAPR比PTS-Companding算法的PAPR优化了0.7dB左右；引入误差与压扩算法相当,但是PAPR比压扩算法的PAPR优化了1dB左右；计算复杂度与PTS算法相当,但是PAPT比PTS算法PAPR优化了2.2dB左右；比原始信号优化了4.5dB左右。因此本文提出的叠加训练序列的PTS-Companding联合算法可以在不增加计算复杂度的情况下,降低峰均功率比,提高LED通信系统的通信质量。
[Abstract]:LED can realize high speed communication at the same time as lighting. It has the characteristics of high communication speed, safety, anti electromagnetic interference and so on, so it has a wide application prospect. However, because of lighting requirement, multiple LED arrays are used as signal emitters, which result in multipath effect and decrease communication quality. For this reason, the MIMO-OFDM modulation method, which can resist multipath and transmit simultaneously, has been applied. However, the signal in MIMO-OFDM is composed of several sub-channel signals. With the superposition of the same direction in the signal, it will inevitably lead to a higher PAPR (Peak-to-Means ratio). The experimental results show that the higher PAPR results in the nonlinear distortion of the signal passing through the correlator. Therefore, reducing PAPR is an important way to improve the quality of visible light communication system based on MIMO-OFDM. At present, the methods to reduce the peak-to-mean ratio can be divided into three categories: probabilistic class, signal predistortion class and coding class. The probabilistic algorithm can reduce the PAPR, of the system without increasing the bit error rate, but the computational complexity of this algorithm is increased and the effect of reducing PAPR is not obvious. The signal predistortion class algorithm has simple structure and obvious effect, but it will increase the bit error rate of the system. Starting from the first two kinds of algorithms, this paper fully balances the computational complexity, reduces the effect of PAPR and introduces the error. In this paper, we propose a joint use of partial transmission sequence (PTS) of probabilistic class algorithm and compression spread (Companding) algorithm of signal predistortion class algorithm, PTS-Companding algorithm to reduce the PAPR. of the system. By studying the relationship between signal autocorrelation and peak-to-average ratio, we can further reduce the PAPRo theoretical analysis and MATLAB simulation of the system by superposing the training sequence with low autocorrelation. The computational complexity and the introduced error of the improved algorithm are similar to that of the PTS-Companding algorithm, but PAPR optimizes 0.7dB compared with the PAPR of the PTS-Companding algorithm. The introduced error is equivalent to that of the Companding algorithm, but the PAPR of the PAPR algorithm optimizes the 1dB; the computational complexity is similar to that of the PTS algorithm, but the PAPT optimizes the 2.2dB or so compared with the PTS algorithm, and the 4.5dB is optimized than the original signal. Therefore, the proposed PTS-Companding joint algorithm for superposition training sequences can reduce the peak-to-average power ratio and improve the communication quality of LED communication systems without increasing computational complexity.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1
本文编号：2350069
[Abstract]:LED can realize high speed communication at the same time as lighting. It has the characteristics of high communication speed, safety, anti electromagnetic interference and so on, so it has a wide application prospect. However, because of lighting requirement, multiple LED arrays are used as signal emitters, which result in multipath effect and decrease communication quality. For this reason, the MIMO-OFDM modulation method, which can resist multipath and transmit simultaneously, has been applied. However, the signal in MIMO-OFDM is composed of several sub-channel signals. With the superposition of the same direction in the signal, it will inevitably lead to a higher PAPR (Peak-to-Means ratio). The experimental results show that the higher PAPR results in the nonlinear distortion of the signal passing through the correlator. Therefore, reducing PAPR is an important way to improve the quality of visible light communication system based on MIMO-OFDM. At present, the methods to reduce the peak-to-mean ratio can be divided into three categories: probabilistic class, signal predistortion class and coding class. The probabilistic algorithm can reduce the PAPR, of the system without increasing the bit error rate, but the computational complexity of this algorithm is increased and the effect of reducing PAPR is not obvious. The signal predistortion class algorithm has simple structure and obvious effect, but it will increase the bit error rate of the system. Starting from the first two kinds of algorithms, this paper fully balances the computational complexity, reduces the effect of PAPR and introduces the error. In this paper, we propose a joint use of partial transmission sequence (PTS) of probabilistic class algorithm and compression spread (Companding) algorithm of signal predistortion class algorithm, PTS-Companding algorithm to reduce the PAPR. of the system. By studying the relationship between signal autocorrelation and peak-to-average ratio, we can further reduce the PAPRo theoretical analysis and MATLAB simulation of the system by superposing the training sequence with low autocorrelation. The computational complexity and the introduced error of the improved algorithm are similar to that of the PTS-Companding algorithm, but PAPR optimizes 0.7dB compared with the PAPR of the PTS-Companding algorithm. The introduced error is equivalent to that of the Companding algorithm, but the PAPR of the PAPR algorithm optimizes the 1dB; the computational complexity is similar to that of the PTS algorithm, but the PAPT optimizes the 2.2dB or so compared with the PTS algorithm, and the 4.5dB is optimized than the original signal. Therefore, the proposed PTS-Companding joint algorithm for superposition training sequences can reduce the peak-to-average power ratio and improve the communication quality of LED communication systems without increasing computational complexity.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1
【参考文献】
相关期刊论文 前10条
1 王辰越;;LiFi来了:灯泡变身路由器[J];中国品牌;2013年12期
2 李恩玉;邹本杰;廖海黔;;基于最优PTS技术的低复杂度算法研究[J];计算机应用研究;2012年01期
3 郁聪;康艳兵;;“中国绿色照明工程”实施——“十一五”回顾与“十二五”规划建议[J];建设科技;2010年14期
4 张立;朱娜;张宁;;室内LED光无线通信多径效应抑制[J];通信技术;2010年07期
5 傅倩;陈长缨;洪岳;邓椺;;改善室内可见光通信系统性能的关键技术[J];自动化与信息工程;2010年02期
6 马杨军;胡耀明;;一种基于训练序列的改进的OFDM同步算法[J];光通信研究;2009年06期
7 王灵垠;曹叶文;;降低OFDM系统峰均功率比的低计算复杂度PTS方法[J];通信学报;2009年10期
8 吴淑梅;霍彦明;;LED光源的应用及前景[J];灯与照明;2008年03期
9 黄润林;周克;;利用伪随机序列降低OFDM系统PAPR方法[J];电子科技大学学报;2007年S3期
10 周洋;刘耀进;赵玉虎;;LED可见光无线通信的现状和发展方向[J];淮阴工学院学报;2006年03期
相关硕士学位论文 前1条
1 江晓明;室内LED可见光无线通信系统物理层研究[D];江苏大学;2008年
，本文编号：2350069
本文链接：https://www.wllwen.com/kejilunwen/wltx/2350069.html
