Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Combined Source-Channel Coding of Images under Power and Bandwidth Constraints | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 49172 9 pages doi 2007 49172 Research Article Combined Source-Channel Coding of Images under Power and Bandwidth Constraints Nouman Raja 1 Zixiang Xiong 1 and Marc Fossorier2 1 Department of Electrical and Computer Engineering Texas A M University College Station TX 77843 USA 2 Department of Electrical Engineering University of Hawaii Honolulu HI 96822 USA Received 8 June 2006 Revised 9 October 2006 Accepted 14 October 2006 Recommended by Stephen Marshall This paper proposes a framework for combined source-channel coding for a power and bandwidth constrained noisy channel. The framework is applied to progressive image transmission using constant envelope M-ary phase shift key M-PSK signaling over an additive white Gaussian noise channel. First the framework is developed for uncoded M-PSK signaling with M 2k . Then it is extended to include coded M-PSK modulation using trellis coded modulation TCM . An adaptive TCM system is also presented. Simulation results show that depending on the constellation size coded M-PSK signaling performs to dB better than uncoded M-PSK signaling. Finally the performance of our combined source-channel coding scheme is investigated from the channel capacity point of view. Our framework is further extended to include powerful channel codes like turbo and low-density parity-check LDPC codes. With these powerful codes our proposed scheme performs about one dB away from the capacity-achieving SNR value of the QPSK channel. Copyright 2007 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION Shannon s separation principle 1 states that source coding and channel coding could be optimized individually and then operated in a cascaded system without sacrificing optimality. Therefore traditionally channel coders are designed independently of the actual source while source coders are designed without considering the
