Research On Key Technology Of Baseband Signal Processing For Satellite Communication Receiver

Convolutional code and RS code as a channel coding method,which has a wide range of applications in the field of wireless,satellite and other communication systems.Viterbi algorithm is the maximum likelihood decoding algorithm of convolutional code.The algorithm has good performance,fast speed,and the hardware implementation structure is relatively simple.It is the best convolutional code decoding algorithm.For RS code has strong capability to correct burst and random errors,the research on encoding and decoding of RS codes is meaningful.OQPSK is a modulation technology developed on the basis of QPSK and widely applied in digital communication.This paper mainly studies the decoding of convolutional codes(Viterbi decoding),RS decoding and the demodulation of OQPSK signals in baseband signal processing.Our studies firstly makes an introduction to the research background and significance,the development status of Viterbi decoding,RS decoding and OQPSK signals demodulation are analyzed.Secondly,the design and implementation of Viterbi decoding algorithm based on FPGA are studied emphatically,a Viterbi decoder based on in-situ operation is proposed,and a multi-channel multiplexing scheme is adopted,this architecture has fast decoding speed and saves resources.In order to explain the key technology of baseband signal processing in a more comprehensive way,the RS decoding algorithm and OQPSK demodulation algorithm are introduced respectively and the rationality of the algorithm are illustrated.Viterbi decoding algorithm used in the paper,using the hardware description language Verilog,the programming of each sub module and the implementation of overall system are given,each module is simulated with Modelsim,corresponding with the simulation results of MATLAB,to verify the correctness of the algorithm.