Td-scdma System, Joint Detection And Smart Antenna Technology Applied Research

TD-SCDMA, which combines the advantage of the time division duplex (TDD) with CDMA, makes use of many advanced techniques, such as smart antenna, Joint Detection, uplink synchronization and so on. TD-SCDMA is the most efficient in using the spectrum in the three main standards. There is the most important significance for researching TD-SCDMA system now.Aiming at the key technology-Joint Detection and smart antenna-of TD-SCDMA standard, this dissertation does a deeply and systemic theoretical analysis and research. And this dissertation accomplishes the arithmetic's DSP realization of base station.This dissertation briefly introduces the standard and the main characters of TD-SCDMA in foreword, and analyses the development and research status of Joint Detection and smart antenna. Subsequently this dissertation analyses the characters and simulation method of mobile communication's wireless channel. A tapped delay line channel model is built based on power delay profile and is used in space-time channel model widely adopted in smart antenna's simulation platform of the TD-SCDMA system. The coefficients of the TDL model are configured according to the suggestion of 3GPP's Multi-In-Multi-Out channel model. The newly built tapped delay line model includes the basic characters and main parameters of space-time channel, so the correctness and consistency of the TD-SCDMA model is ensured.The dissertation builds up an uplink's continuous-time propagation model of the TD-SCDMA system and gives out the matrix denotation of discrete-time propagation model. Focus analysis is made on the construction of system matrix which is the kernel of Joint Detection. Detailed introductions are made on the Joint Detection's algorithm based on Cholesky factorization operation and Fast Fourier Transforms operation of block-circulant matrix. Simulation results under different test environment, number of user equipments and antenna configure for Joint Detection algorithms are presented. The simulation explains the various factors on the performance of the Joint Detection.Finally, a hardware implementation flow of Joint Detection algorithm is given and fix-point simulation is done on Freescale's DSP. Compare results shows the feasibility of the algorithm. The heart part of Joint Detection algorithm-Cholesky factorization is analyzed and commentated in detail. A briefly conclusion is made to the dissertation and figure some directions and ideas for this research.