| Summary: | 碩士 === 國立中正大學 === 電機工程研究所 === 92 === With the increasing population of mobile users and innovation of technology, mobile communications are emerging from voice-based service to data-based service. Multimedia communications over wireless channels have become an interesting topic in recent research. Due to the variety of multimedia, how reduces the redundancy of images over limited-bandwidth channel. Compression technology is employed for this. However, its correlated dependency between the transmitted bit increases the potential of error propagation which will degrade the quality of reconstruction images. Although channel coding can correct the error caused by channel noise, it increases transmission rate and processing time. Thus, in this thesis, we design a joint source and channel coding with feedback scheme to increase the performance of image transmission over wireless channels.
Turbo code, proposed in 1993, has become the most popular scheme for channel coding. Its decoding ability by iteration can achieve near the Shannon limit. However, it doesn’t provide the stop criteria for joint source and channel coding. Thus, in this thesis, we employ Turbo code with error detection code such as CRC and parity check to determine the stop criteria and weight extrinsic values with feedback from the Turbo decoding process to increase the performance of the communication system.
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