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通过引入正交空时编码方案,文中给出了基于各种空时编码的多用户CDMA系统,研究了该系统在多天线Rayleigh衰落信道下的性能.针对空时编码CDMA系统,提出了一种低复杂度多用户接收机方案,该方案可利用空时编码的复正交性简化已有方案的高译码复杂度.与已有方案指数性译码复杂度相比,所提方案具有线性复杂度.在此基础上,给出了系统性能分析,并利用相关数学计算,详细推导了系统平均误比特率(BER),得到了比较紧的平均BER闭式表达式.仿真结果表明所获得的平均BER理论值与相应的仿真值是一致的,而且所提的接收机方案可实现与原有方案相近的性能.在相同系统吞吐量和级联码情况下,所给出的满速率空时编码要好于相应的满分集空时编码CDMA系统,有较低的误比特率.
By introducing orthogonal space-time coding scheme, a multi-user CDMA system based on space-time coding is presented in this paper, and the performance of the system under multi-antenna Rayleigh fading channel is studied.For the space-time coding CDMA system, a Low complexity multi-user receiver scheme, this scheme can simplify the high decoding complexity of the existing scheme by using the complex orthogonality of space-time coding. Compared with the exponential decoding complexity of existing scheme, the proposed scheme has linearity On this basis, the system performance analysis is given, and the relative error bit rate (BER) of the system is deduced in detail by using the relevant mathematical calculation, and the comparatively closed average BER closed-form expression is obtained. The simulation results show that the obtained BER The average BER theoretical value is consistent with the corresponding simulation value, and the proposed receiver scheme can achieve similar performance as the original scheme.With the same system throughput and concatenated code, the given full-rate null When encoding is better than the corresponding full-diversity space-time coding CDMA system, with a lower bit error rate.