异步CDMA通信系统中的小波多用户检测器

针对多用户检测的特点,将小波变换引入异步码分多址(CDMA)系统中上行链路的多用户检测.在发送端对数据进行一维小波重构,在接收端对接收到的信号总和进行一维小波分解,然后对分解得到的两组信号分别进行多用户检测.该小波多用户检测器的相关矩阵的维数只与用户数有关,与数据帧的长度无关,从而极大地简化了相关矩阵的求逆,并可实现逐比特检测.仿真结果表明,小波多用户检测器具有较低的误比特率和较好的抗远近干扰能力.

Wavelet based multiuser detector for asynchronous CDMA channels

Ccording to the characteristics of multiuser detection, wavelet transform was incorporated into the multiuser detection in uplink asynchronous code division multiple access (CDMA) channels. To realize the wavelet multiuser detector, single-level wavelet reconstruction was performed on data at the transmitter, and single-level wavelet decomposition was performed on the sum of all received signals at the receiver. Then, multiuser detection was applied to each of the two signal groups obtained by wavelet decomposition. The dimension of the correlation matrix of the wavelet multiuser detector depends only on the number of users,and has no relation with the frame length. This property reduces significantly the computation complexity of inverting the correlation matrix; and ensures the implementation of bit-by-bit detection. Simulation results show that the wavelet multiuser detector can achieve relatively lower bit-error rate (BER) and better near-far resistance ability.