.4-d-8psk-tcm Decoding Algorithm And Its Implementation

The Four-Dimensional 8PSK Trellis Coded Modulation(4D-8PSK-TCM) system is recommended for the Earth Exploration Satellite Service(EESS) 8025-8400MHz band, due to the SFCG bandwidth efficient definition, the ratio of the source bit rate over the channel symbol rate is at least 1.75 . This system can achieve the coding gains without expanding the bandwidth relative to the un-coded signal set. So it can improve the modulation efficiency greatly. Now 4D-8PSK-TCM is adopted to be an applied design standard for the Near-Earth satellite data transmission. Therefore, it is of great importance to carry out the research on 4D-8PSK-TCM.In this thesis, the coding theory and Viterbi decoding algorithm of TCM system is studied firstly. And then, a software decoder of 4D-8PSK-TCM recommended by the CCSDS is done. The following work is the system's bit error rates performance (BER) simulation. Using the simulation result, the quantization parameters are confirmed and the path management method is chosen. Also an aim about clock-frequency and data rates is proposed here. After that, the system s hardware design is implemented on the Xilinx Virtex-4 SX35 FPGA using Verilog HDL.Finally, the hardware decoder can operate with a clock-frequency of 100MHz and the peak data rates can achieve 250Mbps. The final operational tests demonstrate that the hardware decoder works properly.