Studies On Implementation Of IEEE802.16e LDPC Codes

Low Density Parity Check (LDPC) code is a kind of forward error correction codes with excellent performance and low complexity decoding algorithms. It is becoming more popular than Turbo codes and receiving more and more attention in the field of communication. Its excellent performance makes LDPC code an optional channel code of WiMAX. LDPC codes based on IEEE802.16e standard is an architecture-aware LDPC code and is created by circular right shifted identity matrixes, and its implementation friendly encoding and decoding algorithms allow it to have higher parallel degree and decode throughput.Firstly, we review the history of the development of channel code, and then introduce the current research status of LDPC code and the development of IEEE802.16 standards. Secondly, we give normal LDPC codes in the form of Matrixes, Tanner graph and degrees. Then we introduce the detailed structure of IEEE802.16e standard LDPC codes.The author researches IEEE802.16e standards deeply, finds LDPC code's Efficient encoding algorithms that can support multi-code-length LDPC codes based on IEEE802.16e standard by the way of comparing and analyzing the implementation complexity of three encoding algorithms proposed in IEEE802.16e standard. The Matlab simulation helps to promote the new encoding algorithm which suits the IEEE80.16e standard well and reduces complexity further. Based on the promoted Efficient algorithm the author gives the structure of hardware design method and finishes the RTL codes in Verilog. Finally, the co-simulation of Matlab and Modelsim has convinced us of the fact that the design is functionally correct and meets our demand.The paper finishes the analysis of LDPC decoding algorithms based on IEEE802.16e standards and analysis of hardware implementation. With the help of simulation and analysis of belief propagation and the improved BP decoding algorithms, the author finds the best decode algorithm by comparing many decoding algorithms and software simulation using MATLAB and finds optimized parameters using density evolution. The author introduces a new kind of serial decoder architecture of low density parity check code that can support LDPC codes based on IEEE802.16e standard. We complete RTL code and synthesis on QuartusII software.