Rake接收机中信道最大多普勒频移估计的一种新方法及其在信道估计中的应用

Ｒａｋｅ接收机是ＣＤＭＡ系统中实现多径分集接收的核心部件，而信道估计对其接收性能有很大影响。传统连续导频符号的信道估计是采用对固定区间的信道参数估计值进行平均的方法以抑制接收噪声。

A Novel Estimation Method of Maximum Doppler Frequency in Rake Receiver and its Application in Channel Estimation

In this paper, the estimation of maximum Doppler frequency of fading channels will be investigated. In Rake receiver of direct-sequence code division multiple access (DS-CDMA) systems, channel estimation is carried out via a pilot channel (symbols), which is transmitted simultaneously to the data channel (symbols). In the channel estimation, an averaging process is involved, which for long averaging period suppresses the noise influence efficiently. On the other hand, long averaging intervals lead to systematic errors in the estimated channel coefficients due to the time-variant behavior of the channel and this error is closely related to the maximum Doppler frequency f_d. Taking into account these effects, a novel estimation method of f_d is presented which uses the instantaneous channel coefficients of the pilot symbols of the strongest finger in Rake receiver. This helps to adaptively optimize the averaging period and as a result the BER performance of the receiver could be improved.