Micro-satellite Communication System Channel Coding And Its Hardware Realization

During satellite telemetry process, data transmission is affected by various space noises. That leads to aborted telecommunication mission. There are two ways to solve the problem. One is to improve the Signal Noise Ratio, and the other is to encode data with Error Control Codes (ECC) before transmitting. In case of the former method, more power for transmission, or larger antenna is needed, so the method is used less and less in practical application. With the appropriate choice of VLSI and ECC, the latter method is proved to have more outstanding characteristic. Using channel encoding can improve the veracity of space information transmission. Among many ECCs, Reed - Solomon Codes (RS Codes) and Convolutional Codes have more excellent performance.There exit channel codes that make it possible to achieve reliable communication, with as small error probability as desired. Inside the environment of space channel, the Consultative Committee for Space Date System recommends using concatenated codes to encode space data. The concatenated codes are composed of outer codes - RS Codes (255,223), interleave, and inner codes -Convolutional Codes (2,1,7). The codes can help to resist the signal loss by noises, interference or degradation, and adjust the balance between error control and constrained bandwidth, between power and bandwidth.The paper mainly focuses on the FPGA-oriented implementation of space channel coding according to the need of Micro-satellite telemetry and command system during telecommunication. Those have been finished :Analyzing the basic procedure of satellite channel encoding;Introducing the Convolutional Codes encoding and its Viterbi decoding;Programming encoding and decoding of (2,1,7) Convolutional Codes withVerilog language;Confirming the program and simulating it by software "Modelsim";Implementing Viterbi decoder with FPGA development board.