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传统的多用户处理是在上行进行的 ,本文提出了应用于TDD CDMA系统中下行方向的一种多用户处理方案 .在TDD CDMA系统中 ,可以利用上行信道参数对下行信道参数做出估计 .本文提出了一种实时利用信道参数来降低CDMA中的多用户干扰的方法 .在该方案中 ,其多用户处理的基本思路是通过优化系统的多用户扩频码字和解扩码字来降低多用户干扰 .为了达到最大的信干比 ,本文提出了系统扩频码选择的优化准则 ,它能够充分利用信道的特性 .本文根据一定的迭代算法给出优化问题的解 .数值分析结果表明 ,采用上述方案的CDMA系统相对于采用Gold码的系统能够极大地降低多用户干扰 ,提高信干比 .
Traditional multi-user processing is performed in the uplink, and a multi-user processing scheme applied in the downlink direction in the TDD CDMA system is proposed in this paper.In the TDD CDMA system, uplink channel parameters can be used to estimate the downlink channel parameters. A method to reduce the multi-user interference in CDMA by using channel parameters in real time is proposed.In this scheme, the basic idea of multi-user processing is to reduce multi-user by optimizing multi-user spreading code and despreading code of the system In order to achieve the maximum signal-to-interference ratio, this paper proposes an optimization criterion for system spreading code selection, which can make full use of the channel characteristics.In this paper, we give the solution to the optimization problem based on a certain iterative algorithm.The numerical analysis shows that using the above Compared with the system using Gold code, the CDMA system of the scheme can greatly reduce the multi-user interference and improve the signal-to-interference ratio.