多速率DS-CDMA信号信道参数的估计

Channel estimation of multi-rate DS-CDMA signals

在CDMA通信系统中 ,信道参数的估计 ,特别是信号传输时延的估计是一个重要问题 ,但是在异步CDMA通信系统中 ,传输时延和幅度的估计会受到远近效应的影响 .文中使用最大似然 (ML)估计 ,实现了多速率DS CDMA信号的信道参数估计 .仿真结果表明 ,该算法可有效估计多速率DS CDMA信号的幅度和其相对时延 ,对远近效应稳健 ,其性能接近Cramer Rao界 (CRB) 。

Channel estimation is very important in CDMA communication systems. However, in asynchronous CDMA communication systems the channel estimation of the multipath signals will be degraded by the near far effect. An efficient near far robust estimator is proposed in this paper, which is an extension of the Maximum Likelihood estimator to deal with the channel estimation of the multirate DS CDMA signals. The estimator is shown to be robust against the near far problem and can offer noticeable performance improvement over the conventional sliding correlator.