tailieunhanh - Báo cáo hóa học: " Research Article Combined Source-Channel Coding of Images under Power and Bandwidth Constraints"

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