Design And Implementation Of The PDSCH In Simulated And Analytical System Of LTE Physical Layer

With the development and application of mobile telecommunication technology,LTE(Long Term Evolution)has been widely using in communnication device.Physical,as the bottom layer of this protocol,holds an important status.And so,it is very significant for software engineer who manufactures the mobile communication based on LTE and tests it to design and implement a simulated and analytical platform about LTE physical layer.PDSCH(Physical Downlink Shared Channel)is at the core of the whole physical channel,which bears all the data processing.Therefore,this thesis designs and implements the PDSCH in a simulated and analytical platform about LTE physical layer.Firstly,this thesis brought a brief idea of the key technologies for LTE protocol,such as OFDM technology,MIMO(Multi-Input&Multi-Output),frame structure and physical resource information.What's more,the central techniques in PDSCH including CRC,Turbo-encoding and FFT and so on were also researched in this thesis.The thesis analyzed the background of the simulated and analytical platform about LTE physical layer and provided a specific outline design.Meanwhile,the detailed demand of PDSCH was concerned,and split in two parts:Bit-Level and Symbol-Level.The main research work include:Achieve the 3 kinds of CRC algorithm including look-up table,Galois's method and parallel processing by the C language.Galois field multiplication instructions of TI company was designed to function to achieve CRC algorithm.And,the parallel processing adopted the logical relationship between the input bits and the CRC results,which derived from the math formula.By contrasting the performance of look-up table,Galois's method and parallel processing,the Galois's method was used to achieve CRC process in the end.Turbo-encoding and rate matching were achieved in this thesis.Such as,the code processing and forced zero processing of subencoder,the internal interweaving device implementation of Turbo encoding and sub-block interlace in rate matching.According to the LTE protocol,this thesis completed the interference processing,and then,provided a simple and effective method to achieve modulation process.This thesis provided highly effective approach to modulate bit information and accomplish the processing of FFT/IFFT.Finally,the thesis demonstrated the result of key function in PDSCH and proved the correctness of procedure with the help of Matlab.