提出了一种适用于空时比特交织编码调制系统的低复杂度迭代检测算法,利用交织器的随机特性和中心极限定理,将各天线发送信号在接收端的叠加近似为高斯分布的随机变量,避免了矩阵求逆运算,从而可适用于任意根接收天线的情况.在此基础上,利用序列译码原理搜索所有可能的信号向量,计算各天线发送信号的估计值,并利用该估计值计算每个比特的外信息,完成迭代译码.与现有算法相比,新算法可在不损失性能的前提下降低计算复杂度.
A new low complexity iterative detection algorithm is proposed for the space-time bit interleaving coded modulation system. By utilizing the characteristics of the interleaving and the central limited theorem, the superstition of the transmitted signals at the receiver is first assumed as a Gaussian random variable. Therefore, the matrix inverse calculation can be avoided, which enables the proposed method to be used in a system with more transmitter antennas than receiver antennas. Under the previous assumption, P most significant symbol combinations are identified via the sequential principle to calculate the log likelihood ratio of each bit, which will be used by the iterative decoding. Compared with the available sequential algorithm, the proposed method reduces the complexity without sacrificing any performance.