分层空时码分多址系统的快速联合检测算法

Fast Joint Detection Algorithm for Layered Space-time Code Division Multiple Access System

分层空时码分多址系统(LST-CDMA)的联合检测算法(JD)利用扩频码和信道冲击响应(CIR)卷积形成的空-时二维特征向量来进行多用户和多天线检测,能够获得优良的检测性能。但是该JD算法的复杂度非常高,针对这个问题提出了两种快速算法:近似Cholesky分解和块-Fourier算法。为了进一步减少运算量,又利用重叠保留法(OLA)对块-Fourier算法进行改进。仿真证明,这些算法在几乎不降低检测性能的前提下,可以大幅降低计算复杂度。

Joint detection （JD） algorithm of Layered Space-Time Code Division Multiple Access （LST-CDMA） system can work on multiple-user and multiple-antennas detection efficiently with good error performance by exploiting the space-time specific signatures, which is the convolutional result of spreading code and channel impulse response. However, the complexity of JD is too high to be implemented in real system. Two fast algorithms were proposed for the issue： one is approximated Cholesky decomposition and the other is block-Fourier algorithm. To reduce the computations further more, the over-lap and save （OLA） technique was employed in block-Fourier algorithm. Simulation results prove that the algorithms achieve great reduced complexity with little performance degradation.