基于盲信号分离的回波抵消技术

Echo cancellation based on blind source separation

针对数字直放站回波抵消技术中自适应滤波法在多径回波信道条件下不能完全消除次径回波的问题,提出了基于盲信号分离的直放站回波抵消方法。首先对施主天线接收的混合信号进行相空间重构,使观测信号的数目大于等于独立信源的数目;然后利用独立分量分析法(ICA)对重构的信号进行盲信号分离;最后根据各分离信号和发送信号的相关情况判断有用信号,实现回波消除。对复杂多径回波信道条件下的多载波全球移动通信系统(GSM)信源进行回波抵消测试,分离得到的有用信号的相关系数可以达到0.9593。表明盲信号分离的方法可以实现复杂多径信道下的直放站回波抵消,有效解决了传统的自适应滤波法存在的问题。

An echo cancellation method on digital repeater of mobile communication system was presented to solve the problem of traditional adaptive filter, which cannot eliminate the sub-path echo in complex muhipath channel. Firstly, based on phase space reconstruction theory, the signal that came from the donor antenna and contained echo was reconstructed; hence, the number of sensors was not fewer than the number of sources in blind source separation. Secondly, Independent Component Analysis （ICA） algorithm was used to separate reconstructed signal. Finally, desired signal was determined by the correlation of sent signal and separated signal. In the experiment on the multi-carrier Global System of Mobile communication （GSM） source with complex multipath echo, correlation coefficient of desired signal was up to 0. 959 3. The echo cancellation method based on blind source separation proves to be an effective way to eliminate the echo in complex muhipath channel.