| WCDMA is one of the candidate projects for the 3rd generation wireless communication system. Its key technologies are widely studied in the wireless communication area in recent years. In this paper, we have studied several key technologies such as WCDMA's three step cell search, frequency acquisition, RAKE receiver, channel estimation and path search. For the reason that wireless communication works in the complex radio environment, radio channel simulation is also studied and realized in this paper.We choose Matlab/Simulink as our simulation software and pipe-line searching schedule as the searching schedule of WCDMA's three step cell search. The realization methods for the first step and the second step cell search are proposed in this paper. The inner characters of the codes of P-SCH and S-SCH together with the frequency errors are fully considered. The method proposed in this paper can get higher searching efficiency and needs less hardware resource at the same time. Frequency acquisition should be carried out following the initial cell search, a method based on FFT and quadratic interpolation is proposed in this paper, which can result in higher estimation precision and shorter acquisition time.RAKE receiver is an efficient diversity receiver. We introduce an improved realization structure of the RAKE receiver named chip matched filter (CMF) receiver in this paper. Comparing with the conventional Rake receiver, the CMF receiver needs fewer correlaters and has lower BER. Performance of channel estimation and path search is closely connected with that of the receiver. We introduced two kinds of pilot aided channel estimation methods in this paper, one is correlation method, and the other is based on adaptive signal processing. Realization algorithms and correspond performance curves for both channel estimation methods are given in this paper. The aim of the path search is to identify the signal from the noise; we introduced an efficient noise identification algorithm in this paper. |
PDF Full Text Request