The Simulation And Development Of WCDMA Uplink RAKE Receiver

WCDMA is one of the main technologies in the third generation mobile communication technology, which has been researched extensively and deeply all over the world. In the mobile communication system, the randomicity of users'mobility, the spread of multi-path and other factors due to the geographical environment of complex and diversity, make the transmission channel complex. Using RAKE diversity reception technology, WCDMA system receiver decomposes the frequency selective path into a number of non-selective transmission paths of independent fading characteristics, and then makes max-ratio combination of the separated multi-path signal, which will improve the quality of received signal.RAKE receiver is one of the core technologies in the WCDMA system,so the selection of its algorithm is key for the performance of the system.This paper provides an implementation design of uplink RAKE receiver for WCDMA system,which has good performance and is easy to be realized.The receiver is mainly made up of three parts:Multi-path Searching and Tracking,Channel Estimation and Signal Merging.Dynamic control is used in the Multi-path Searching module,which ensures that the performance can be good in large SNR range.The algorithm of the Channel Estimation module is WMSA,which uses the coherence between the channel changes to improve the precision.And MRC is selected in the Signal Merging module.In the paper, firstly we give the characteristics and mathematical model of the land mobile radio channel. Then, we studied the diversity receiver technology and the principle of RAKE receiver so that the reader will have a rough understanding of CDMA system receiver. After that, the model of RAKE receiver and the algorithm designs of all the modules are given in Chapter 3. In Chapter 4, we provide the simulated results which prove that this design has good performance. In Chapter 5, the structure of DSP and some points of how to design programme are introduced. At last the architecture of fixed point platform is briefly illustrated. Finally, we analyse the realization complexity of the major modules in RAKE receiver.