【摘要】 Rake接收机是CDMA系统抗多径的有效手段,信道估计对其性能有很大的影响。传统方法是利用连续多个时隙的导频段估计出的信道参数,再对估计值进行平均。这种固定平均的方法不适合3G系统信道变化范围大的环境。本文提出了直接利用每个导频段的信道参数的包络来估计最大多普勒频移,再运用指数平滑法来调整各被估计时隙的权值的信道估计方法。仿真结果表明,该方法能准确有效地估计出信道参数,改善系统性能。1更多还原

【Abstract】 The Rake receiver, of which the performance heavily relies on channel estimation precision, is an effective anti-multipath method in CDMA systems. The conventional channel estimation method is to average the channel parameters which are derived during pilot symbol transmission. The method is not appropriate for third generation mobile communication systems where channels have wide variation range. This paper proposes a novel channel estimation method, in which the maximum Doppler frequency shift is firstly estimated from the envelope of the channel parameters during the pilot symbol period. Then an exponential smoothing method is applied to adjust the weighting factors of the slots being averaged. Simulation results show that the channel parameters can be accurately estimated and system performance is consequently improved.更多还原