分布式空时码协同通信系统简化均衡方法

摘要： 由于协同通信系统各中继节点分布位置的不同，产生了不同于传统多天线通信系统的多时偏问题. 该文考虑基于分布式线性卷积空时码的异步协同通信系统，将对应每个中继节点的时延偏移量等效到对应生成多项式中的零矢量，进而构造等效的异步协同通信系统模型. 对等效信道矩阵的带状Toeplitz 性质进行研究，提出一种基于Trench 算法求解带状Toeplitz 线性系统的块最小均方误差均衡方法，从而将求解高阶带状Toeplitz 线性系统的运算简化为求解低阶Toeplitz 线性系统的运算，避免了传统最小均方误差均衡算法中的高阶矩阵求逆运算，极大地降低了计算复杂度. 仿真结果表明，该均衡方法能在适当的数据帧长以及较大的时延量情况下取得满意的系统性能.

Simplified Equalization for Cooperative Communication Systems Based on Distributed Space-Time Codes

Different from traditional multi-antenna systems,cooperative communication systems are inherently time-asynchronous due to the nature of relay distribution.In this paper,we investigate cooperative communication systems based on distributed linear convolutional space-time codes.An equivalent asynchronous system model is obtained by converting the relays’ transmission delays to a zero vector of the corresponding generator polynomials.With the banded Toeplitz property of the equivalent channel matrix,we propose a block minimum mean square error equalization method using the Trench algorithm to solve the Toeplitz linear systems.In the proposed equalization method,computation of the high order banded Toeplitz linear system is simplified to that of a low order system.The method avoids high order matrix inversion operations of the traditional minimum mean square error equalization method,leading to substantial reduction of computational complexity.Simulation results show that satisfactory system performance can be achieved with non-minimumorder non-trace-orthogonal generator polynomials,proper data frame length and large delay.