| For the WCDMA downlink channel of mobile communication system,the spectrum analysis and signal analysis have received extensive attention in the wireless communication field.Especially under the premise of improving the national security level,the analysis of the uplink and downlink signals can play a key role in solving the problem of wireless signal detection.The main work of this paper is to complete the analysis and implement the algorithm of downlink signals of WCDMA.The author used the tester SP8010B to send downlink WCDMA signals,and managed to complete the WCDMA downlink signal analysis and algorithm implementation through several processes such as cell search,RAKE reception,channel transmission and multiplexing,and system message parsing.This thesis firstly clarified the research background and significance of the topic,and studied the standard and technical characteristics of 3GPP on WCDMA downlink channel.The cell search process of WCDMA signals was explored through experiments,and detailed analysis was performed on the time slot synchronization,frame synchronization,and primary scrambling code identification in cell search;Multipath searching,channel descrambling and despreading,channel estimation,and maximum ratio combining are analyzed in detail by understanding the key technologies of RAKE receivers.The designing method of WCDMA signal RAKE receiver is studied,and an improved method is proposed for the frequency correction algorithm at the receiver end,and verified by Matlab.It is proved that the proposed algorithm improves the receiving performance.The author also studied the process of WCDMA downlink signal channel transmission and multiplexing and correctly acquired the BCH message block.By analyzing the scheduling mechanism of WCDMA system messages,a set of WCDMA system message parsing and scheduling process was designed.By reducing the number of parsed frames and maintaining the scheduling information table,the parsing efficiency of system messages got improved. |
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