The Applied Research Of CTC Based On WiMAX System

CTC is a channel coding technology adopted by WiMAX system,and owning the thought of coding and decoding of Turbo code,it's the key technology to enhance the reliability of communication system.Adopting the duo-binary circular recursive systematic convolutional coder,CTC possesses flexible code words,also it has flexible selection ranges of frame length and code rate,and compared with classical Turbo code,CTC owns the advantages such as a better coding efficiency,a good error-correcting performance under decoders with the same complexity,and a short decoding delay,etc.,and while effectively enhancing the coding efficiency,by setting the encoder's circular state,CTC can eliminate the impact on the decoding performance by tail-biting.The paper mainly studies the technology scheme of practical communication system with the application of CTC under the background of the task.The thesis first narrates the channel coding technology and its development, briefly introducing several channel codes with excellent performance.Then the paper analyzes WiMAX system,as well as the key technology in WiMAX system--OFDM.Then the thesis mainly studies the basic principle of coding and decoding of CTC,along with a couple of decoding algorithms:MAP algorithm, Log-MAP algorithm,Max-Log-MAP algorithm,and gives a detailed derivation to the above-mentioned algorithms.Through theoretical analysis,according to the feature of CTC code's circular trellis,the thought of introducing state transition in decoding algorithm is acquired,thus obtaining the excellent decoding performance.In accordance with the theoretical analysis,the computer simulation of several key factors affecting CTC's performance is conducted,thus providing a theoretical basis for CTC code's hardware realization.Afterwards,the thesis mainly studies CTC's application in the practical systems,that is,the communication system with high bandwidth efficiency and WiMAX system,and respectively integrating OFDM and other different modulation modes,the corresponding computer simulations are conducted,and from the result of the simulations,we can get that CTC is a channel code with excellent performance, and also we have explored the technology scheme of CTC combining MSK modulation under the background of the task.