Research On The Key Technologies And The Implementation Of The PDSCH Channel Of TD-LTE System

This paper studies on the key technologies of Physical Downlink Shared Channel(PDSCH) in TD-LTE system’s physical layer and the implementation of it on TMS320C6670 multi-core DSP platform.The first part of this paper introduces the development of TD-LTE’s standard and it analyzes the background and significance of TD-LTE system. Then the protocol’s framework of TD-LTE system are summarized. At the end of this part, the key technologies of TD-LTE system are systemized.The second part of this paper firstly studies on the key technologies of the PDSCH’s transmitter according to the technical standard of the TD-LTE protocol. Secondly, the structure and function of PDSCH are summarized. Meanwhile, the design process and the algorithm of submodules are analyzed. Then, this paper accomplishes the simulation of PDSCH’link and compares the link’s data with the standard data obtained from the link level simulation platform of LTE provided by the university of Vienna and the Agilent. And it proves that the understanding to the protocol is correct.The third part of this paper mainly studies on some MIMO detecting algorithms of the PDSCH, including Maximum Likelihood Detection(ML), Zero Forcing Detection(ZF), Minimum Mean Square Error Detection(MMSE), ZF-serial interference cancellation(ZF-SIC) and MMSE-serial interference cancellation(MMSE-SIC). The theoretical analysis and the simulation results are given to show that the ZF algorithm is appropriate for the early implementation of the PDSCH’s receiver.The forth part of this paper firstly introduces TMS320C6670 multi-core DSP chip and studies on operating mechanism of the communications port programming interface(CPPI) and bit rate coprocessor(BCP). Secondly, this chapter studies overall design of the PDSCH’s receiver and analyzes the allocation of resources on multi-core DSP platform. Thirdly, this chapter analyzes the process of the PDSCH implementation and accomplishes a functional implementation and test on some key modules of the PDSCH’s receiver, including the CRC, the code block’s segmentation, rate matching, modulation and so on. Meanwhile, this chapter compares these modules’ data with The corresponding modules’ s standard data from the link level simulation platform of LTE provided by the university of Vienna. Then, this chapter accomplishes a functional implementation and test on ZF detecting algorithms and analyzes the data scaling and the method of the optimization on multiplication and division. Meanwhile, this chapter compares the DSP implementation’s fixed-point data with the floating point data from the simulation result on MATLAB. At last, this paper analyzes the conditionthe that different data scaling in fixed-point implementation will affect the performance of the system and compares the performance of different data scaling’s system according to the simulation.In the end of this paper, the conclusions are made. What we should research on in the future is also proposed.