Algorithm Research On Multipath Search In Uplink Receiver Of Wcdma System

In order to reach higher data rate, several solutions for HSPA Evolution have been introduced into the WCDMA system, which greatly improve the user data rate and system capacity. The latest 3GPP release support the 16-Quadrature Amplitude Modulation (16QAM) and boosting which increase the peak rate to 11.4Mbps. And the introduction of CPC mitigates interference between users in the uplink so that system throughput is increased. What is more, the traditional RAKE receiver is replaced by the Generalized Rake receiver which can reduce inter-symbol interference by using additional noise finger and whitening colored noise.After analysis of the basic wireless propagation environment, this paper presents a detailed description of the RAKE and GRAKE receiver. First, key algorithms of the RAKE receiver such as channel estimation, SIR estimation, MRC, frequency offset estimation and frequency off compensation etc. are investigated and discussed. The parameters for real time processing are given. Secondly, the architecture and algorithms of GRAKE receiver are introduced and analyzed; especially, the algorithm for noise finger selection is given in detail.As searcher is an important module in the GRAKE receiver, the simulation and analysis of the search algorithms are presented in the paper. To ensure the successful implementation of the searcher, the performance and complexity of the algorithms are balanced. According to the characteristics of HSPA signals, some parts of the searcher like threshold calculation and sidelobe suppression are optimized. The EOL interpolation algorithm which is base on conventional interpolation algorithm is proposed since the EOL interpolation algorithm achieves higher accuracy than conventional interpolation algorithm. Simulations of the improved algorithms are carried out, and the results and conclusions are given in the end.