OFDM系统中基于迭代和门限理论降低PAPR的改进PTS方法  

Improved PTS Methods of Peak to Average Power Ratio Reduction Based on Flipping and Threshold Theory for OFDM Systems

作　　者：巩朋成[1] 黎锁平[2] 侯尚林[2] 王克融[1] 

机构地区：[1]兰州理工大学计算机与通信学院,甘肃兰州730050 [2]兰州理工大学理学院,甘肃兰州730050

出　　处：《信号处理》2010年第8期1263-1268,共6页Journal of Signal Processing

基　　金：教育部"春晖计划"基金(Z2006-1-62006);甘肃省自然科学基金(0809RJZA019);甘肃省高校研究生导师科研基金(0603B-03;0703-10)资助

摘　　要：传统的部分传输序列法(PTS)中,如果要得到最佳的相位旋转因子,需要遍历所有的可选相位,这样的计算量随分割的子序列数按指数增长。本文提出两种减少计算复杂度的改进PTS方法(经迭代的IPTS和经门限的IPTS)。这两种方法都利用快速傅立叶变换(FFT)的时域循环移位特性增加备选信号,改善PAPR降低的性能。首先提出了一种利用反复迭代移位的IPTS方法(经迭代的IPTS),该方法的计算量随子序列数按线性增长。接着提出了一种利用预先设定的门限值以降低计算复杂度的IPTS方法(经门限的IPTS)。最后理论分析、比较了PTS、PTS/CSS方法与本文方法的计算复杂度。Matlab软件仿真显示,当使用相同的分割子序列数和相位旋转因子时,两种IPTS方法能够以较小的运算量达到了PTS/CSS方法性能;两种IPTS方法降低PAPR的性能要优于PTS方法,但计算复杂度并没有增加。In order to get optimum phase weighting factors, Partial transmit sequence method （PTS） requires the exhaustive search over all combinations of the allowed phase factors, and the search complexity increases exponentially with the number of sub- blocks. To solve this problem, two improved partial transmit sequence methods （Flipping IPTS and Threshold IPTS ） are presented. In our methods, a cyclic shift of the Fast Fourier Transform （FFT） in the time domain is employed to improve the PAPR reduction per- formance. Furthermore, the paper makes use of iterative flipping algorithm to reduce computational complexity. The search complexity of the iterative flipping IPTS increases linearly with the number of sub-blocks. In order to reduce the computational complexity dramatic- ally, a threshold is introduced to reduce the complexity. The theory shows the computational costs of PTS, PTS/CSS and proposed methods. The Matlab simulation results show that when the same number of sub-blocks and phase weighting factors, the proposed two IPTS methods have similar performance as PTS/CSS method with lower computational complexity, and achieve better performance than PTS method with comparable computational complexity.

关 键 词：峰均比 部分传输序列方法 FFT 反复迭代 门限 

分 类 号：TN929.5[电子电信—通信与信息系统] TN914.3[电子电信—信息与通信工程]