Wyner-Ziv coding based on TCQ and LDPC codes and extensions to multiterminal source coding

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Title: Wyner-Ziv coding based on TCQ and LDPC codes and extensions to multiterminal source coding
Author: Yang, Yang
Abstract: Driven by a host of emerging applications (e .g . , sensor networks and wireless video ) , distributed source coding (i .e . , Slepian -Wolf coding , Wyner -Ziv coding and various other forms of multiterminal source coding ) , has recently become a very active research area . In this thesis , we first design a practical coding scheme for the quadratic Gaussian Wyner -Ziv problem , because in this special case , no rate loss is suffered due to the unavailability of the side information at the encoder . In order to approach the Wyner -Ziv distortion limit D ? ?W Z (R ) , the trellis coded quantization (TCQ ) technique is employed to quantize the source X , and irregular LDPC code is used to implement Slepian -Wolf coding of the quantized source input Q (X ) given the side information Y at the decoder . An optimal non -linear estimator is devised at the joint decoder to compute the conditional mean of the source X given the dequantized version of Q (X ) and the side information Y . Assuming ideal Slepian -Wolf coding , our scheme performs only 0 .2 dB away from the Wyner -Ziv limit D ? ?W Z (R ) at high rate , which mirrors the performance of entropy -coded TCQ in classic source coding . Practical designs perform 0 .83 dB away from D ? ?W Z (R ) at medium rates . With 2 -D trellis -coded vector quantization , the performance gap to D ? ?W Z (R ) is only 0 .66 dB at 1 .0 b /s and 0 .47 dB at 3 .3 b /s . We then extend the proposed Wyner -Ziv coding scheme to the quadratic Gaussian multiterminal source coding problem with two encoders . Both direct and indirect settings of multiterminal source coding are considered . An asymmetric code design containing one classical source coding component and one Wyner -Ziv coding component is first introduced and shown to be able to approach the corner points on the theoretically achievable limits in both settings . To approach any point on the theoretically achievable limits , a second approach based on source splitting is then described . One classical source coding component , two Wyner -Ziv coding components , and a linear estimator are employed in this design . Proofs are provided to show the achievability of any point on the theoretical limits in both settings by assuming that both the source coding and the Wyner -Ziv coding components are optimal . The performance of practical schemes is only 0 .15 b /s away from the theoretical limits for the asymmetric approach , and up to 0 .30 b /s away from the limits for the source splitting approach .
URI: http : / /hdl .handle .net /1969 .1 /2516
Date: 2005-11-01

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Wyner-Ziv coding based on TCQ and LDPC codes and extensions to multiterminal source coding. Available electronically from http : / /hdl .handle .net /1969 .1 /2516 .

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