码分多址系统中基于小波变换的多用户检测

针对多用户检测的特点，利用小波变换，在降维的同时对接收到的信号按用户进行了分组，然后对每一组信号进行多用户检测。用户分组使得多用户检测处理的用户数减少。这样，既使得多用户检测的性能得以提高，补偿了由于降维带来的性能损失，又使得有些检测算法的运算量得以降低。仿真结果表明，同满维的多用户检测器相比，在高信噪比下，降维算法的性能有所下降，在低信噪比或用户数较多的情况下，两者的性能基本相同。

Multiuser Detection Based on Wavelet Transform in Direct Sequence CDMA Systems

A reduced dimension multiuser detection based on wavelet transformation is proposed. With wavelet transformation, at the receiver, the user signal dimension is reduced and at the same time the signals of different users are separated into several groups. And then multiuser detection is applied to each group. Multiuser detector has the character that its performance increases with the decrease of the number of users. The separation of users implies that the number of input users of multiuser detection decreases. That makes up the performance decrease caused by the dimensional reduction and reduces the computation load of some multiuser detectors. Simulation results confirm that compared with full dimension multiuser detection, the performance decreases under the condition of high input SNR, but not decreases under the condition of low input SNR and large number of users.