Design And Optimization Of Decoder Of LDPC Code Based On WiMax 802.16e Standard

Low Density Parity Check (LDPC) code has excellent performance and the complexity of the decoding algorithm is linear with the length of the code. It becomes more popular than Turbo code in communication. IEEE WiMax 802.16e standard is the next step toward very high throughput wireless backbone architectures. LDPC code is an optional channel code in IEEE WiMax 802.16e standard.Firstly, we review the history of the development of channel code, and then introduce the current reseach status of LDPC code. Secondly, we introduce LDPC code and its encoding algorithm briefly and analyze the decoding algorithm deeply. Offset min-sum algorithm is chosen to be hardware implementation algorithm finally. We focus on the design of the architecture of the decoder based on IEEE WiMax 802.16e standard. And choose layered decoding to optimize the algorithm implementation. We modified and optimize the minimum model to suit to different variable degree and also analyze the difference between RAM and DFF and choose an appropriate mode to storage the data. The pipeline is designed to suit to the layered decoding algorithm. We discuss the consistency of the data and design the sequence of the signal. The decoder is completed with Verilog HDL and successfully verified on MATLAB-Modelsim mixed platform and synthesised on XILINX Virtex-II pro FPGA platform. Finally, we compare the used resource with other decoders.The decoder of LDPC code designed by the author works at 110MHz and throughput is about 71 to 268Mbps and latency is about 5.7μs to 26.8μs.