Research On Key Technologies Of LDPC Codes In Spatial Communication

The low-density parity-check codes are one of error correction codes the most closest to the Shannon limit,and has excellent performance and is widely concerned by the industry.In the field of mobile communications,including 3Gpp,IEEE and other standardization organizations recommend their own LDPC code as a mobile communication channel coding standard.In the field of space communication,ETSI,CCSDS and other spatial communication standardization organizations also choose the appropriate LDPC code as a spatial communication channel coding standard.According to the characteristics of spatial communication,the key technologies realized by LDPC codes as channel coding schemes include high-speed coding,rate-compatible coding and low-power coding,which are required in near-space communication and deep space communication.In this paper,these key technologies will be analysised and researched,the main research work is as follows:1.In this paper,a low parallelism coding method is proposed and implemented on the basis of CCSDS standard recommendation 7/8 code rate LDPC serial coding architecture.Then,an ultra-high-speed LDPC coding architecture with a coding throughput of 2.5Gbps is proposed by optimizing the low parallelism coding method,and the hardware implementation result and analysis of this ultra-high speed coding architecture are given.2.Based on the low parallelism coding method,a kind of high efficiency low parallelism LDPC coding method with configurable cyclic matrix and implementation architecture are proposed in the low power consumption scenario for space communication.By adding a suitable cyclic shifter controller to the encoder’s cyclic shifter,the cyclic shifter can select the number of shifts based on the characteristics of the input information bit to be encoded,thereby reducing the average number of shifts,reducing the coding power consumption.In this paper,the shift control algorithm and coding architecture are given.3.The ETSI recommends the second generation of digital video broadcasting standards(DVB-S2)in variable-coded modulation scenarios for space communications.The standard recommends the use of BCH code and LDPC code concatenation code as a channel coding scheme.In this paper,a new multi-rate compatible LDPC coding circuit architecture is proposed based on DVB-S2 standard multi-rate coding algorithm,which can realize the coding of all 11 kinds of code rates in DVB-S2 standard,In this paper,the results and analysis of the hardware implementation of this coding architecture.4.The CCSDS in the spring of 2016 released the blue book recommended three ultra-short block LDPC code as the next generation of uplink channel coding scheme.This paper studies the structural characteristics of this ultrashort block code,and gives the appropriate coding and decoding algorithm and architecture design scheme.In the aspect of coding,an efficient coding scheme is proposed,and an efficient coding architecture is proposed.In the aspect of decoding,a highly efficient low coupling decoding algorithm is proposed to accelerate the iterative convergence.The(256,128)LDPC decoder architecture design based on the decoding algorithm is proposed.This kind of ultra-short block LDPC code has the characteristics of less resource cost and simple structure of codec,and has great application prospect in the future space communication uplink.