| Low-Density Parity-Check(LDPC)code,referred to as LDPC code,is a kind of Forward Error Correction(FEC)code.Due to its excellent error correction performance,it has been widely used in fiber optic communication,space communication,high-speed storage and other fields in recent years.Quasi-Cyclic Low-density Parity-Check(QC-LDPC)code is a code type with special structure in LDPC code,which has similar error correction performance with LDPC code.QC-LDPC codes have a broader application prospect than LDPC codes,and are widely used in broadband satellite communication,IEEE 802.11 n standard,CCSDS standard,5G NR and many other fields.Broadband satellite communication network relies on synchronous orbiting satellites as antenna base stations to support wide-area communication network access,and is the network with the widest space range among wireless communication networks at present.Broadband satellite communication has excellent features such as flexible networking,portable equipment,cross-territory communication and high scalability,and has wide applications in ocean exploration,polar research,military combat and other fields.With the development of broadband satellite communication,QC-LDPC codes are also gradually applied to broadband satellite communication systems,and the design of high-throughput decoders compatible with multiple code rates for various customized code lengths and code rates of QC-LDPC codes has become an urgent need in this field.The paper is centered on the above problem,and the main research contents include.Firstly,LDPC codes used in broadband satellite communication are studied,the background knowledge of broadband satellite communication is introduced,and the advantages and characteristics of using LDPC codes as channel coding in broadband satellite networks are analyzed.The basic concepts of LDPC codes and the two basic coding algorithms of LDPC codes are discussed,as well as the relevant parameters affecting the error correction performance of LDPC codes.Based on LDPC codes,QC-LDPC codes are introduced,their structural features and construction methods are discussed,and the excellent performance is analyzed in terms of hardware implementation.Next,the Belief Propagation(BP)algorithm of LDPC codes is studied.The calculation steps of decoding algorithms including BP,LLR-BP,MS and MS related improved algorithms,OMS and NMS,etc.are deduced.The performance and hardware complexity of each decoding algorithm are compared,and it is determined that the NMS algorithm is used in this paper.Decoding algorithm and hardware implementation.Finally,an improved QC-LDPC decoder design is proposed,and the synthesis and simulation of the hierarchical parallel decoder are completed on the Vivado platform of Xilinx.The results show that the decoder is compatible with five types of custom QC-LDPC codes in broadband satellite communication with low resource occupation and high maximum decoding throughput rate.After the synthesis and simulation,a back-link signal reception and processing terminal was designed for the wideband satellite communication system,and the decoder was downloaded based on XILINX’s XC7K410T-2FFG900 I platform.The test results show that the decoder meets the expected design requirements and can realize the broadband satellite signal decoding function. |
