The Research Of LTE Baseband Software Processing Based On X86

In recent twenty years, from early GSM system to the current LTE system,the technology of mobile communications has made remarkable progress,But,that also results in a wide range of mobile communication systems coexist.How can cost-effectively achieve a variety of network standards coexist has becoce the subject of the communication industry. With the reduction in power consumption, and the advantages of high performance and programming flexibility, the use of general-purpose processors based on X86 architecture to achieve a communication system attract more researchers. This paper is to explore the possibility of using the general processor based on X86 architecture to implement LTE systems.The main work of this thesis includes the following three parts.(1) First, LTE system uplink channel is presented briefly and implemented with C programming language. After thousands of tests,the average processing time of the respective processing module is calculated.Finally,we find the two of the most timeconsuming moudules:Transform precoding and Turbo decoder.In order to reduce the running time of the program,we study the optimization method based on X86 architecture:the the SSE parallel computing instruction set and look up table.(2) The mathematical theory of transform precoding is Discrete Fourier Transform. Since direct DFT algorithm requires a large amount of multiply-add operation,we design the Fast Fourier Transoform algorithm based on mixed radix with the radix of 2,3,4 and 5,combining the characteristics of LTE systems transform precoding. With a length of 300 DFT Case, the author present the mixed radix algorithm implementation process and describe the use of SSE instructions to achieve a length of 3 DFT calculations.Finally,we test the performance of the mixed radix FFT algorithm implemented by SSE instructions.(3) The MAP series decoding algorithms of the turbo code are studied,and on this basis,the author research the parallel decoding algorithm of turbo code based on MAXLOG-MAP algorithm.With the simulation to turbo parallel decoding algorithm based on MAX-LOG-MAP by Matlab,we determine the number of iterations and the fixed quanlization scheme.The author presented the implementation framework of turbo parallel decoding algorithm and focused on the use of SSE instructions to parallel implementation of branch metric、forward metric、backward metric and log likehood ratio.Finally,the performance of turbo parallel decoding algorithm is tested.