Wireless sensor networks (WSNs) are the core component in the big data era. Due to the unreliable transmission environment, it is significantly useful to introduce a helper to refine the system performance. To begin w...
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ISBN:
(纸本)9781538660096
Wireless sensor networks (WSNs) are the core component in the big data era. Due to the unreliable transmission environment, it is significantly useful to introduce a helper to refine the system performance. To begin with, we formulate the system model of WSNs as a problem of multiterminal source coding. Subsequently, we propose a 3D distributed compress-bin scheme and derive a corresponding inner bound by analyzing the expected rate-distortion. Finally, we investigate the performance improvement of a helper by comparing the derived inner bound with the Berger-Tung inner bound and through simulation. Both the theoretical bounds and simulation results indicate that a helper can obviously improve the system performance.
We consider the distributed sourcecoding system of two correlated Gaussian Vector sources (Y) under bar (l) = (t)(y(l1), Y-l2), l = 1,2 which are noisy observations of correlated Gaussian scalar source X-0. We assume...
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We consider the distributed sourcecoding system of two correlated Gaussian Vector sources (Y) under bar (l) = (t)(y(l1), Y-l2), l = 1,2 which are noisy observations of correlated Gaussian scalar source X-0. We assume that for each (1, k) is an element of {1, 2}, Y-lk is an observation of the source X-0, having the form Y-lk = XO Nlk, where N-lk is a Gaussian random variable independent of X0. We further assume that N-lk, (1, k) E {1,2}2 are independent. In this system two correlated Gaussian observations are separately compressed by two encoders and sent to the information processing center. We study the remote sourcecoding problem where the decoder at the center attempts to reconstruct the remote source Xo. The determination problem of the rate distortion region for this communication system can be regarded as an extension of the Gaussian CEO problem to the case of vector observations. For each vector observation we can obtain an estimation on X-0 from this observation. Those estimations are sufficient statistics on X-0. Using those sufficient statistics, we determine the rate distortion region by showing that it coincides with the rate distortion region of the CEO problem where the scalar observations of X-0 are equal to the estimations computed from the vector observations. We further extend the result to the case of L terminal and general vector observations.
Wyner-Ziv coding (WZC) is a compression technique which uses decoder side-information to help reconstruction. The vector WZC is a key element to solve the vector Gaussian CEO problem for sensor networks. Compared with...
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ISBN:
(纸本)9781424410361
Wyner-Ziv coding (WZC) is a compression technique which uses decoder side-information to help reconstruction. The vector WZC is a key element to solve the vector Gaussian CEO problem for sensor networks. Compared with the scalar CEO problem, in the vector CEO problem sensor node array is used by each agent and a vector source is to be estimated. In this paper, we present a nested-lattice based vector WZC structure, which is a generalization of the scalar WZC proposed by Zamir et al.. The key is to explore the duality between the WZC problem and the dirty paper coding (DPC) problem. This coding structure is shown to be able to achieve the Berger-Tung sum rate, which is the best known compression rate for the CEO problem.
We evaluate the performance of the successive coding strategy for the problem of multiterminal lossy coding of correlated Gaussian sources. We consider the m-helper problem for the special case of m = 1 where one sour...
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ISBN:
(纸本)9781424405053
We evaluate the performance of the successive coding strategy for the problem of multiterminal lossy coding of correlated Gaussian sources. We consider the m-helper problem for the special case of m = 1 where one source provides partial side information to the decoder to help reconstruction of the main source signal. Our results reconfirm the fact that the successive coding strategy is an optimal strategy in sense of achieving the rate-distortion function of the 1-helper problem. Comparing the performance of the sequential coding with the performance of the successive coding, we show that there is no sum rate loss when the side information is not available at the encoder. Finally, based on the successive coding strategy, we provide an achievable rate-distortion region for the m-helper problem.
multiterminal (MT) video coding is a practical application of the MT sourcecoding theory. For MT sourcecoding theory, two problems associated with achievable rate regions are well investigated into in this thesis: a...
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multiterminal (MT) video coding is a practical application of the MT sourcecoding theory. For MT sourcecoding theory, two problems associated with achievable rate regions are well investigated into in this thesis: a new sufficient condition for BT sum-rate tightness, and the sum-rate loss for quadratic Gaussian MT sourcecoding. Practical code design for ideal Gaussian sources with quadratic distortion measure is also achieved for cases more than two sources with minor rate loss compared to theoretical limits. However, when the theory is applied to practical applications, the performance of MT video coding has been unsatisfactory due to the difficulty to explore the correlation between different camera views. In this dissertation, we present an MT video coding scheme under the H.264/AVC framework. In this scheme, depth camera information can be optionally sent to the decoder separately as another source sequence. With the help of depth information at the decoder end, inter-view correlation can be largely improved and thus so is the compression performance. With the depth information, joint estimation from decoded frames and side information at the decoder also becomes available to improve the quality of reconstructed video frames. Experimental result shows that compared to separate encoding, up to 9.53% of the bit rate can be saved by the proposed MT scheme using decoder depth information, while up to 5.65% can be saved by the scheme without depth camera information. Comparisons to joint video coding schemes are also provided.
A firm's CEO employs a team of L agents who observe independently corrupted versions of a data sequence {X(t)}(t=1)(infinity). Let R be the total data rate at which the agents may communicate information about the...
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ISBN:
(纸本)0780324536
A firm's CEO employs a team of L agents who observe independently corrupted versions of a data sequence {X(t)}(t=1)(infinity). Let R be the total data rate at which the agents may communicate information about their observations to the CEO, The agents are not allowed to convene, Berger, Zhang, and Viswanathan determinined the asymptotic behavior of the minimal error frequency in the limit as L and R tend to infinity for the case in which the source and observations are discrete and memoryless. We consider the same multiterminal source coding problem when {X(t)}(t=1)(infinity) is independent and identically distributed (i.i.d.) Gaussian random variable corrupted by independent Gaussian noise, We study, under quadratic distortion, the rate-distortion tradeoff in the limit as L and R tend to infinity, As in the discrete case, there is a significant loss between the cases when the agents are allowed to convene and when they are not, As L --> infinity, if the agents may pool their data before communicating with the CEO, the distortion decays exponentially with the total rate R;this corresponds to the distortion-rate function for an i.i.d. Gaussian source, However, for the case in which they are not permitted to convene, we establish that the distortion decays asymptotically only as R-1.
Following recent works on the rate region of the quadratic Gaussian two-terminal sourcecoding problem and limit-approaching code designs, this paper examines multiterminal source coding of two correlated, i.e., stere...
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Following recent works on the rate region of the quadratic Gaussian two-terminal sourcecoding problem and limit-approaching code designs, this paper examines multiterminal source coding of two correlated, i.e., stereo, video sequences to save the sum rate over independent coding of both sequences. Two multiterminal video coding schemes are proposed. In the first scheme, the left sequence of the stereo pair is coded by H.264/AVC and used at the joint decoder to facilitate Wyner-Ziv coding of the right video sequence. The first I-frame of the right sequence is successively coded by H.264/AVC Intracoding and Wyner-Ziv coding. An efficient stereo matching algorithm based on loopy belief propagation is then adopted at the decoder to produce pixel-level disparity maps between the corresponding frames of the two decoded video sequences on the fly. Based on the disparity maps, side information for both motion vectors and motion-compensated residual frames of the right sequence are generated at the decoder before Wyner-Ziv encoding. In the second scheme, source splitting is employed on top of classic and Wyner-Ziv coding for compression of both I-frames to allow flexible rate allocation between the two sequences. Experiments with both schemes on stereo video sequences using H.264/AVC, LDPC codes for Slepian-Wolf coding of the motion vectors, and scalar quantization in conjunction with LDPC codes for Wyner-Ziv coding of the residual coefficients give a slightly lower sum rate than separate H.264/AVC coding of both sequences at the same video quality.
Wireless sensor networks (WSNs) are the core component in the big data era. Due to the unreliable transmission environment, it is significantly useful to introduce a helper to refine the system performance. To begin w...
详细信息
ISBN:
(纸本)9781538660102
Wireless sensor networks (WSNs) are the core component in the big data era. Due to the unreliable transmission environment, it is significantly useful to introduce a helper to refine the system performance. To begin with, we formulate the system model of WSNs as a problem of multiterminal source coding. Subsequently, we propose a 3D distributed compress-bin scheme and derive a corresponding inner bound by analyzing the expected rate-distortion. Finally, we investigate the performance improvement of a helper by comparing the derived inner bound with the Berger-Tung inner bound and through simulation. Both the theoretical bounds and simulation results indicate that a helper can obviously improve the system performance.
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