Study On The Implementation Scheme Of Joint Receiver

TD-SCDMA system is the third generation of mobile communication system in china withindependent intellectual property rights, which is one of the three main standards for thethird-generation mobile communication systems. TD-SCDMA employs many advanced techniques,such as Time Division Duplexing (TDD), Joint Detection (JD), Smart Antenna (SA), and so on. So,it is a very effective way to improve the spectral efficiency.Joint Detection, a necessary core technology of TD-SCDMA, can reduce the multiple accessinterference (MAI), multiple path interference (MPI), and Near-Far effects. Based on the techniquesof beam-forming and the Direction of Access (DOA) estimation, SA can improve the systemperformance. So it is necessary to combine SA technique with JD realization.First, this thesis introduces the principle of multiple user detection. After this, the thesisanalyses the simulation performances of three kinds of linear Joint Detection algorithms inTD-SCDMA. Then a result has been proved that Joint Detection can eliminate MPI and MAIabsolutely, but the ability of eliminating the additive noise in the system is limited, and it has a greatdependence on channel estimation. Then, three kinds of improved algorithms of the system matrix,which are Cholesky Decomposition algorithm, Approximate Cholesky Decomposition algorithmand Fourier algorithm for cyclic block matrix, are given in this thesis. In the end, a scheme ofeliminating MPI by using the local de-spreading code and Mid-amble code is given in the thesis. Atthe same time an improved scheme of the receiver with JD based on the DOA estimation of SA isgiven in the thesis. Some problems about multi-cell interference when using multi-cell JD arediscussed in the thesis, and a solution has been given.