计算机应用 ›› 2018, Vol. 38 ›› Issue (10): 2950-2954.DOI: 10.11772/j.issn.1001-9081.2018030721

• 网络与通信 • 上一篇    下一篇

空间调制系统下改进的QRD-M检测算法

周围1, 郭梦雨1,2, 向丹蕾1,2   

  1. 1. 移动通信技术重庆市重点实验室(重庆邮电大学), 重庆 400065;
    2. 重庆邮电大学 通信与信息工程学院, 重庆 400065
  • 收稿日期:2018-04-10 修回日期:2018-05-11 出版日期:2018-10-10 发布日期:2018-10-13
  • 通讯作者: 郭梦雨
  • 作者简介:周围(1971-),男,重庆人,教授,博士,主要研究方向:无线移动通信、通信系统及信号处理、多输入多输出天线技术;郭梦雨(1993-),女,河南平顶山人,硕士研究生,主要研究方向:无线移动通信、信号检测;向丹蕾(1994-),女,重庆人,硕士研究生,主要研究方向:无线移动通信、信号检测。
  • 基金资助:
    重庆市基础与前沿研究计划项目(cstc2015jcyjA40040)。

Improved QRD-M detection algorithm for spatial modulation system

ZHOU Wei1, GUO Mengyu1,2, XIANG Danlei1,2   

  1. 1. Chongqing Key Laboratory of Mobile Communications Technology(Chongqing University of Posts and Telecommunications), Chongqing 400065, China;
    2. School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
  • Received:2018-04-10 Revised:2018-05-11 Online:2018-10-10 Published:2018-10-13
  • Supported by:
    This work is partially supported by Foundation and Frontier Research Project of Chongqing (cstc2015jcyjA40040).

摘要: 空间调制(SM)系统中性能最优的最大似然(ML)检测算法复杂度很高,用基于信道矩阵QR分解的M算法(QRD-M)可以降低复杂度,但传统QRD-M算法检测时,每层都保留固定的M个节点,仍会造成额外的计算量。针对传统QRD-M算法中存在的问题,提出一种低复杂度的动态M值QRD-M检测算法——LC-QRD-dM。LC-QRD-dM算法利用设计的阈值与累积分支度量值进行比较,每层自适应地选择不超过M的保留节点数,相对于传统QRD-M算法以牺牲少量性能为代价大大降低了复杂度。接着又针对该改进算法在信道衰落较深时会产生较大误码率的问题,进一步提出一种基于信道状态的动态M值QRD-M检测算法——CS-QRD-dM。CS-QRD-dM利用LC-QRD-dM的原理,在低信噪比(SNR)时,每层根据阈值选择不小于M的保留节点数;在高信噪比时,每层则选择不超过M的保留节点数。理论分析和仿真结果表明:相比传统QRD-M,CS-QRD-dM在低信噪比时有约1.3 dB的信噪比增益(误码率为10-2),以增加少量复杂度为代价,显著地改善了检测性能;在高信噪比时,其检测性能及复杂度与LC-QRD-dM相同。

关键词: 空间调制, 最大似然, 基于QR分解的M算法, 计算复杂度, 信道状态

Abstract: In Spatial Modulation (SM) system, the Maximum Likelihood (ML) detection algorithm with the best performance has high complexity, while the complexity can be reduced by M-algorithm based on QR decomposition (QRD-M) of channel matrix. However, when the traditional QRD-M algorithm is used, fixed M nodes were chosen at each layer, which leads to additional computation. Therefore, for the problem of the traditional QRD-M algorithm, a Low-Complexity QR-Decomposition M-algorithm with dynamic value of M (LC-QRD-dM) was proposed. In LC-QRD-dM, by comparing the designed threshold with the cumulative branch metrics, the number of reserved nodes that does not exceed M was adaptively selected at each layer, thus reducing the computational complexity with the cost of a small amount of performance. Then, concerning the high bit error rate of LC-QRD-dM with deep channel fading, QR-Decomposition M-algorithm with dynamic value of M based on Channel State (CS-QRD-dM) was further proposed. Based on the principle of LC-QRD-dM, the number of reserved nodes that do not less than M was selected by the threshold value at each layer when the Signal-to-Noise Ratio (SNR) is not high; and the number of reserved nodes that do not exceed M was selected by the threshold value at each layer when the SNR is high. Theoretic analysis and simulation results show that, compared with the traditional QRD-M algorithm, CS-QRD-dM achieves about 1.3 dB SNR advantage (when the bit error rate is 10-2) at low SNR, which can significantly improve the detection performance at the cost of small complexity increase; and its detection performance and complexity are the same as LC-QRD-dM at high SNR.

Key words: spatial modulation, maximum likelihood, M-algorithm based on QR decomposition (QRD-M), computational complexity, channel state

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