Performance Comparison Between Joint Receiver And RAKE Receiver In TD-SCDMA

TD-SCDMA is one of the three main standards of 3rd generation mobile communication, which is researched and developed by China independently. In TD-SCDMA, joint detection is a key technology of receiver, which can make full use of multiple access interference(MAI) and to separate all the received signals. While RAKE receiver can achieve diversity reception of multi-path signals, and merge the separated multi-path signals. Thus, RAKE receiver can strengthen the received signal and increase the ratio of signal to noise.Firstly, the basic theory of joint receiver, the related principle diagram and the output formula are derived in this thesis. Then, based on the construction of simulation platform of TD-SCDMA system, three linear joint detection algorithms used commonly are simulated. Comparing the performance curves obtained by simulation, anti interference performance of WMF algorithm is the weakest, while MMSE-BLE’s is the best. But, the complexity for the computation of MMSE-BLE is too high, so ZF-BLE is selected by TD-SCDMA system, which is more eclectic. Finally, the performance comparisons for ZF-BLE algorithm in different situations were carried out by the simulation results obtained.For RAKE receiver, the comparison between the classical RAKE receiver and the coherent RAKE receiver used in 3G systems has be done in this thesis. Then, based on the coherent RAKE receiver, the possibility of the application of RAKE in 4G is discussed, and the diagram of RAKE receiver that could be used for OFDM signal perhaps is tried to be put forward here.