Research On HARQ Key Technology And The RS Coding And Decoding Technology Of HF System

HF communication plays a very important role in the field of communication forit’s feature such as long transmission distance，high flexibility and strong anti-destroy.In recent years， the development of HF communication puts forward a higherrequirement of the data transmission rate and system’s real-time. However，in the HFcommunication system，multipath，fading and Doppler frequency shift will seriouslydeteriorate system performance, while users usually require the system to provide alow probability of packet errors and high system throughput. The hybrid ARQ (HARQ)is one of the effective means to reduce the packet error ratio and to improve the systemcapacity. The HARQ technology，therefore，can be used in HF communication systemto ensure reliable service quality and to reduce the transmission delay. According to thethird generation of HF communication network standard protocolMIL-STD-188-141B，the key technology of data transmission of HF communication isdiscussed, and the HARQ technique in HF communication system is mainly studied.The RS code encoding and decoding technology is also studied in this thesis.The thesis first introduces the data structure of BW2,briefly describes the sendingand accepting program, and do some research on key technique such as the CRC,8PSKand so on.Then, the traditional ARQ protocol mechanism and the working principle ofthree types of HARQ are discussed, codeword merging technique in the HARQ isgiven in detail, and three types of HARQ throughput performance with the Shannontheorem are also analyzed and simulated in this thesis.Secondly the thesis givessimulation about HARQ system based on the convolutional code, and compares itsperformance with traditional ARQ system. At last, the advantages and disadvantages ofthree s of HARQ is discussed, an improved program is given.In additional, the encoding algorithm for RS code which is used widely is studied,BM iterative decoding algorithm as well as Euclid decoding algorithm for RS aremainly studied and the simulation is given in the thesis.