This dissertation is divided into two main topics. In the first topic, we study thejointsource-channelcoding problem of transmitting an analog source over a Gaussianchannel in two cases - (i) the presence of interfe...
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This dissertation is divided into two main topics. In the first topic, we study the
jointsource-channelcoding problem of transmitting an analog source over a Gaussian
channel in two cases - (i) the presence of interference known only to the transmitter and (ii) in the presence of side information about the source known only to the
receiver. We introduce hybrid digital analog forms of the Costa and Wyner-Ziv coding schemes. We present random coding based schemes in contrast to lattice based
schemes proposed by Kochman and Zamir. We also discuss superimposed digital and
analog schemes for the above problems which show that there are infinitely many
schemes for achieving the optimal distortion for these problems. This provides an
extension of the schemes proposed by Bross and others to the interference/source
side information case. The result of this study shows that the proposed hybrid digital analog schemes are more robust to a mismatch in channel signal-to-noise ratio
(SNR), than pure separate sourcecoding followed by channelcoding solutions. We
then discuss applications of the hybrid digital analog schemes for transmitting under
a channel SNR mismatch and for broadcasting a Gaussian source with bandwidth
compression. We also study applications of jointsource-channelcoding schemes for
a cognitive setup and also for the setup of transmitting an analog Gaussian source
over a Gaussian channel, in the presence of an eavesdropper.
In the next topic, we consider joint physical layer coding and network coding
solutions for bi-directional relaying. We consider a communication system where two transmitters wish to exchange information through a central relay. The transmitter
and relay nodes exchange data over synchronized, average power constrained additive
white Gaussian noise channels. We propose structured coding schemes using lattices
for this problem. We study two decoding approaches, namely lattice decoding and
minimum angle decoding. Both the decoding schemes ca
In wireless communication, the channel is characterized by multipath propagation due to scattering by different obstacles. Multiple Input Multiple Output (MIMO) channels which considers this multipath propagation offe...
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In wireless communication, the channel is characterized by multipath propagation due to scattering by different obstacles. Multiple Input Multiple Output (MIMO) channels which considers this multipath propagation offers significant increase in data throughput and link range without additional bandwidth or transmit power. With the availability of high data rates by MIMO channel, images can be transmitted with high reliability. An image is source coded by using Compressive Sensing (CS) algorithm where the input image is converted to bit streams. These bit streams are spatially multiplexed into four data streams which are transmitted simultaneously over the four antennas . The data streams are then channel coded by using 4-Quadrature Amplitude Modulation (4-QAM).Then unequal power allocation scheme is employed where each transmitting antenna gets different amount of power according to the data it transmits. The result is simulated using MATLAB. The results show that the unequal power allocation provides significant quality improvement than the any other technique. The result also reveals that Spatial diversity can be utilized more efficiently using Compressive Sensing.
One method of transmitting wavelet based zerotree encoded images over noisy channels is to add channelcoding without altering the source coder. A second method is to reorder the embedded zerotree bitstream into packe...
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One method of transmitting wavelet based zerotree encoded images over noisy channels is to add channelcoding without altering the source coder. A second method is to reorder the embedded zerotree bitstream into packets containing a small set of wavelet coefficient trees. We consider a hybrid mixture of these two approaches and demonstrate situations in which the hybrid image coder can outperform either of the two building block methods, namely on channels that can suffer packet losses as well as statistically varying bit errors.
This paper proposes an approach for the joint optimization of multiview video coding (MVC) and a forward error correction method based on Turbo codes. The scheme minimizes the reconstructed 3D video distortion at the ...
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ISBN:
(纸本)9781479923427
This paper proposes an approach for the joint optimization of multiview video coding (MVC) and a forward error correction method based on Turbo codes. The scheme minimizes the reconstructed 3D video distortion at the display subject to a constraint on the overall transmission bitrate budget. The minimization is achieved by exploiting the source rate distortion characteristics and the statistics of the available codes. Experimental results show that the proposed approach outperforms conventional equal error protection techniques at different signal-to-noise ratios. It also significantly improves the performance of end to end 3D content transmission at high packet loss rate or low signal-to-noise ratio.
The accuracy of end-to-end distortion (EED) estimation is crucial to achieving effective error resilient video coding. An established solution, the recursive optimal per-pixel estimate (ROPE), does so by tracking the ...
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ISBN:
(纸本)9781467399623
The accuracy of end-to-end distortion (EED) estimation is crucial to achieving effective error resilient video coding. An established solution, the recursive optimal per-pixel estimate (ROPE), does so by tracking the first and second moments of decoder-reconstructed pixels. An alternative estimation approach, the spectral coefficient-wise optimal recursive estimate (SCORE), tracks instead moments of decoder-reconstructed transform coefficients, which enables accounting for transform domain operations. However, the SCORE formulation relies on a fixed transform block size, which is incompatible with recent standards. This paper proposes a non-trivial generalization of the SCORE framework which, in particular, accounts for arbitrary block size combinations involving the current and reference block partitions. This seemingly intractable objective is achieved by a two-step approach: i) Given the fixed block size moments of a reference frame, estimate moments of transform coefficients for the codec-selected current block partition;ii) Convert the current results to transform coefficient moments corresponding to a regular fixed block size grid, to facilitate EED estimation for the next frame. Experimental results first demonstrate the accuracy of the proposed estimate in conjunction with transform domain temporal prediction. Then the estimate is leveraged to optimize the coding mode and yields considerable gains in rate-distortion performance.
A novel jointsourcechannel distortion model is proposed, which can essentially estimate the average distortion. To improve the precision of the model, the redundancy generated by a forbidden symbol in the arithmetic...
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ISBN:
(纸本)9781424472352
A novel jointsourcechannel distortion model is proposed, which can essentially estimate the average distortion. To improve the precision of the model, the redundancy generated by a forbidden symbol in the arithmetic codes is used to distinguish between the quantization distortion and the channel distortion, all the coefficients from the first error one to the end of the sequence are set to be a value within the variance range of the coefficients instead of zero, then the error propagation coming from the entropy coding can be essentially estimated. Experiment results show that the precision of the model in terms of average peak-signal-to-noise has been improved about 0.5dB compared to classical works. An efficient progressive image transmission system based on the model is developed, and can be used in the wireless communication systems.
We study transmission of a memoryless Laplacian source over an average-power limited additive white Laplacian noise (AWLN) channel under bandwidth compression in two cases: 1) matched signal-to-noise ratio (SNR), 2) m...
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ISBN:
(纸本)9781467320726
We study transmission of a memoryless Laplacian source over an average-power limited additive white Laplacian noise (AWLN) channel under bandwidth compression in two cases: 1) matched signal-to-noise ratio (SNR), 2) mismatched SNR. A hybrid digital-analog (HDA) jointsource-channelcoding (JSCC) scheme is proposed and show that this scheme can achieve a distortion very close to the lower bound on mean-absolute error (MAE) distortion under matched SNR conditions.
In this paper, we design a unified framework decoder for relay systems with iterative decoding. In the proposed scheme, the source node needs to transmit a correlated content to a destination with the help of a relay....
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ISBN:
(纸本)9781509043736
In this paper, we design a unified framework decoder for relay systems with iterative decoding. In the proposed scheme, the source node needs to transmit a correlated content to a destination with the help of a relay. Then, a distributed jointsourcechannel (JSC) Low-Density-Parity-Check (LDPC) encoding is applied at the source and the relay. The destination receives simultaneously the source compressed data from the source node, and the source/channel encoded data from the relay node. The cooperative network is mapped into a factor graph on which message passing iterative decoding is applied to estimate the source information. The JSC decoder takes into account the source-relay correlation which involves remarkable improvements even if errors occur at the source-relay link. The Bit Error-Rate (BER) system performance are investigated for different scenario, according to the relay position, and it is shown that the performance of the proposed cooperative scheme is typically about 0.5-1.0 dB better than an equivalent rate pointto-point system.
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