The problem of distributed estimation of an unknown noise-corrupted parameter in wireless sensor networks, with a fusion centre, is considered. convolutionalcoding and rate-compatible punctured convolutional coding a...
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The problem of distributed estimation of an unknown noise-corrupted parameter in wireless sensor networks, with a fusion centre, is considered. convolutionalcoding and rate-compatible punctured convolutional coding are used to protect the transmission of sensor observations and to reduce the impact of noise channels. Two novel kinds of power scheduling based on different encoding methods are derived for minimising the total power consumption. The formulas of the proposed power scheduling suggest that local sensors with poor observation qualities should decrease their quantisation levels. The levels should also be related to coding methods, channel qualities, a given mean squared error (MSE) and local signal-to-noise ratios. Finally, simulation results show that not only these two schemes are energy-efficient but also they can achieve comparable performance of a given MSE.
The high demand for multimedia applications has emphasized the requirement for newer methods for the transmission of video over low-bit-rate error-prone channels. H. 264 video coding provides a versatile video coding ...
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The high demand for multimedia applications has emphasized the requirement for newer methods for the transmission of video over low-bit-rate error-prone channels. H. 264 video coding provides a versatile video coding format suitable for different network and storage applications. The versatility is exposed through a set of encoder control parameters. We investigate the effects of these parameters on the rate, distortion, and algorithm complexity and determine a suitable set of parameters, keeping the low bit-rate wireless channel in perspective. rate-compatible punctured convolutional coding is used to produce code rates varying from 8/9 to 1/4 using the same encoder and the same Viterbi decoder. A feedback-based adaptive forward error correction (FEC) technique is developed to use the ratecompatible codes in the transmission of video, which is especially vulnerable to transmission errors because of the high compression using predictive coding. The proposed system is used to perform joint source-channel coding of video and to study the effects over mobile channel over various E-b/N-0 values. The results are used to develop a channel-adaptive system for the transmission of video over low bit-rate channels. Frame-by-frame adaptation of the video to the channel conditions is simulated to demonstrate that proposed channel-adaptive joint source-channel coding of H. 264 video could utilize the available channel capacity more efficiently than a fixed-coding-based system when transmitting over low-bit-rate error-prone channels. (c) 2006 Society of Photo-Optical Instrumentation Engineers.
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