低信噪比WCDMA信号扩频码的盲估计方法

An approach to blind estimation of PN sequence in low SNR WCDMA signals

针对低SNR(信噪比)下WCDMA(宽带码分多址)上行链路信号OVSF(正交可变扩频因子)码难检测的问题,提出了一种利用WCDMA信号的相关矩阵累加平均与其奇异值分解相结合的方法。该方法是在WCDMA信号的OVSF码周期、码速率等参数已知的前提下,将接收到的信号以一随机固定值为起点进行周期分段,形成多个连续观察向量,求相关矩阵并累加平均,并对相关矩阵进行奇异值分解,由相关矩阵的主特征向量估计出WCDMA信号的OVSF码序列,从而对接收的信号实行盲解扩处理。仿真结果表明,该方法在较低SNR条件下也能取得良好的效果。

In view of the difficulties in the blind estimation of the Pseudo-random Noise （PN） sequence OVSF code for WCDMA uplink signals in low Signal to Noise Ratio （SNR）, an approach is proposed by using the correlation matrix and cumulative av- erage of the signals combined with its singular value decomposition. When such parameters of the WCDMA signals as the OVSF code period and rate are known, the received signals are periodically divided into multiple continuous observation vectors based on the OVSF sequence period with a random fixed value as the starting point for the correlation matrix and cumulative av- erage. Then the OVSF sequence of the WCDMA signals is blindly estimated from the main component eigenvector and the sig- nals are despreaded. Simulation results show this method works well in a lower SNR scenariors.