| The software radio is a wireless communication system that has a standardization and modularization hardware platform, on which Various functions can be accomplished by programmable hardware or software that the platform provided.The main characteristics of the software radio are flexibility and openness. In the meantime, the requirement of the reliability on the communication system is higher and higher due to the rapid development of communication technology. Error-correcting coding technique is an important method that can improve the reliability of information transmission, thus the channel encoder module play a main role in the software radio system. Therefore, it is significant that the channel encoder module is researched on the software radio system.According to the disadvantage that the implement process of decoding cyclic codes is quite complex in the software radio system, this paper designs a novel Error-correcting Code - Tach (named after tache counter), which is easily implemented, by taking advantage of the characters of programmable hardware such as DSP and CPLD etc.Tach codes are encoded by cyclically shifting message codes from left or right side to add redundant information to the message. Tach codes are decoded by reproducing message with every section of received message. Code Reproduced with the section has a minimum distance, compared with received message. At the same time, to get more help of correcting burst-error, if received message has been matched to coding rule with continuous half above section number of the code words, minimum distance algorithm is adopted no longer, but the other algorithm, in which original message is directly reproduced with received section. By the way, the ability of burst-error correction has been greatly improved.Firstly, Tach Error-correcting coding and decoding algorithm and the parameters with engineering importance such as minimum distance of the code and the ability of correcting errors are presented in this paper. Secondly, the codec is compared by simulation with BCH(Bose Chaudhuri Hocquenghem), RS and Hamming, then performance analysis reports are put forward. Finally, the codec has been implemented based on CPLD and the implementation complexity is discussed. The results of our studies show that Tach codes is an efficient and practicable Error-correcting code based on the Software Radio system. |
