Research On LDPC Coding And Spaceborne Multichannel Storage System

The spaceborne storage system is the core of satellite data storage.It has the characteristics of high data throughput,high bandwidth,large capacity,multi type payload data input,and multi task parallel processing and storage.This thesis studies the spaceborne storage system of a certain type of satellite from the Chinese Academy of Sciences.Currently,spaceborne storage systems have problems such as low data reliability,poor versatility of system architecture design schemes,fewer data channels,and low data throughput.This thesis focuses on the high reliability,standardization,versatility,multi-channel,and high throughput of spaceborne storage systems,and mainly studies the following issues.A 2D interleaved LDPC error correction algorithm has been proposed to solve the problem of reduced data reliability caused by single particle effects and storage media.This is a 2D data encoding and decoding architecture that includes two parts:the LDPC-NMSA algorithm and the LDPC LLR-BP algorithm.The thesis completed the AWGN channel simulation analysis,and set the number of iterations to 10,with a bit error rate（BER）of 10^-5.The improved 2D-NMSA and 2D-LLR-BP algorithms have decoding gains of 0.38dB and 0.55dB,compared to the recommended RS（255,223）-LDPC（8176,7154）algorithm in the CCSDS standard.A universal hardware architecture for spaceborne storage systems has been proposed to solve the problem of poor universality and low configurability.The function of this architecture is the storage,playback,and downlink of satellite data.It integrates internal and external communication interfaces such as OC,LVDS,BLK2711,SPI,Space Wire,etc.This architecture is compatible with multiple external payload data protocols and internal communication protocols.It is a multi chip hierarchical storage array architecture that can be configured with 256Gb-4Tb capacity.This architecture improves the universality and standardization process of the system.A multi-channel storage controller for spaceborne storage systems has been proposed to solve the problem of fewer data channels and lower data throughput.This controller has the following functions:data combination,data storage,data multiplexing,and data downlink.This controller is designed to support 7 external load data inputs,using DDR2 SDRAM cache layered multiplexing,and speed priority arbitration based combined packaging technology.It is designed to support a maximum single channel 1.6Gbps transmission rate,and it can be configured as an8-128bit data bus and supports 256Mbps-4Gbps data throughput.Through investigations on data reliability,standardization and generality,and the number and the throughput rate of data channels,the performance of the spaceborne storage system described here is significantly boosted,satisfying the needs of data storage,data playback and data downlinking,etc.in the course of carrying out aerospace missions of this project.