信号空间分集中向量高斯近似算法的改进.pdf

第26卷第4期
数据采集与处理
2011年7月
Journal of Data Acquisition Processing
Jul.2011
文章编号:1004-9037(2011)04-0385-05
信号空间分集中向量高斯近似算法的改进
冯文江王茹茹陈栋才刘震
(重庆大学通信工程学院,重庆,400044)
摘要:针对采用了信号空间分集的通信接收机检測算法的性能提升,以向量高斯近似检测算法为基础,通过改进
原算法中每个符号的概率期望和方差的计算方法,给定符号的軟干扰消除计算的信息依赖关系以及概率密度函
数的计算,以降低算法的复杂度,提升系统的抗衰落能力。对改进算法进行了仿真比较和性能分析。结果表明,在
瑞利衰落信道中,当旋转矩阵维数N=16,选代次数为6时的误比特率曲线与理想边界接近,在误比特率BER=
10-5时,仅相差0.2dB;在时廷要求较高的通信系统应用中,选代4次即可满足要求,且继续增加代次数已没
有误比特率下降裕曼。
关犍词:信号空间分集;格栅;向量高斯近似
中图分类号:TN92
文献标识码:A
Improvement and Anal ysis of Vector Gaussian
Approximation in Signal Space Diversity
Feng Wenjiang, Wang Ruru, Chen Dongcai, Liu Zheng
( College of Communication Engineering, Chongqing University, Chongqing, 400044, China)
Abstract: Focused on the performance improvement of receiver detection algorithm using signal
space diversity, three aspects in the original algorithm are modified based on vector Gaussian
approximation algorithm, including the calculation methods of probability expectation and vari
ance with regarding to each symbol, the information dependence relationship in soft interfer
ence cancellation of the given symbol, and calculation of the probability density function
Therefore, the complexity of the algorithm is reduced and the system performance to resist d
lay is improved. According to simulation results and performance analysis by the new modified
algorithm, under the condition of Rayleigh channels while lattice dimension N=16 and itera
tion number Iter=6, the BER curve is close to the ideal boundary. When bit error rate BER=
105, the performance gap between the Rayleigh fading channel and the Gaussian channel is
only 0. 2 db. In high delay requirement system, there is no degrading space for BER when the
iteration number is four
Key words: signal space diversity; lattice; vector Gaussian approximation
式。采用SSD的通信系统,在衰落信道中的接收
引言
性能有极大提升。信号空间分集的基本思想是将
N个发送符号联合乘以旋转矩阵后发射到空中,
信号空间分集( Signal space diversity,SSD)接收机需要联合检测N个接收符号,解调出每
是J. Boutros和E. Viterbo在1998年提出的。相个信息比特。SSD在众多通信系统中已得到广泛
比于传统的时间、频率和空间分集,SSD是一种不应用和性能验证,文献[2]将LDPC编码与SSD结
额外消耗信道资源、充分利用系统自由度的分集方合,用于在衰落信道下对抗噪声、缓解衰落;文献
基金项目:国家自然科学基金(60872038)资助项目;重庆市自然科学基金重点(CSTC2009BA2064)资助项目;国家
211工程”三期建设(S-09102)资助项目。
收稿日期:2010-05-24;修订日期:2010-09-19