Design And Implementation Of Convolutional Code For Small Satellite User Terminal Based On FPGA

With the continuous advancement of modern science and technology,the need for humans to explore all over the world is increasing,including vast oceans,rugged terrain,snowy mountains,and deserts.Many of them are traditional 2G / 3G / 4G / 5G mobile communications.The system cannot be overwritten.For example,the marine Internet of Things technology requires the interconnection and interconnection of various sensor devices at sea,so as to integrate maritime information,to achieve monitoring and systematic management of complex data at sea,as well as China's erection of high-altitude snow regions in Tibet Snow thickness detector.In the above-mentioned geographical scenario,it is impractical to set up and maintain traditional cellular communication base stations and lay telecommunication optical cables over long distances.And because the satellite communication communicates directly with the user terminal,as long as the terminal is in an open area and there is no object above it,it can achieve high-quality communication with the satellite.The unique advantages of satellite communications are fully demonstrated under the above-mentioned geographical conditions.In order to ensure communication quality,error correction coding is usually an indispensable part of the communication system.Therefore,as with cellular communication systems,satellite communication systems also need to use error correction coding.As a mature FEC error correction code,convolutional code has moderate complexity and provides high coding gain.Therefore,convolutional code is maturely applied to channels such as broadcast channel(BCH)and control channel(CCH)of 4G systems.Medium;although there are newer and stronger error correction codes,such as Turbo codes for 4G data channels(SCH),LDPC and Polar codes for 5G systems,these coding methods require a lot of matrix multiplication calculations and a lot of memory storage.In contrast,because convolutional codes are simple to implement and occupy less resources,under the circumstances that the system rate requirements and the bit error rate are not very high,convolutional codes are a very good "cost-effective" choice.This thesis mainly studies the application of convolutional codes in satellite communication systems to improve the accuracy of information transmission in the system under the same signal-to-noise ratio.The main work of the thesis is as follows:1.On the basis of extensive learning of channel coding and decoding knowledge,the convolutional code algorithm and its hardware implementation scheme are studied in depth.2.Introduce the uplink and downlink communication processes and related algorithms of the user terminal signal processing unit.3.According to the design requirements of satellite terminal systems,FPGA hardware implementation schemes of convolutional encoder and decoder are given,and detailed simulation and analysis are performed in MATLAB.4.Using Xilinx's Virtex-7 series FPGA chip as a development platform,the convolutional code encoding module and decoding module in the satellite communication terminal system were implemented,and simulation verification and resource evaluation were performed.