source and channel coding over multiuser channels in which receivers have access to correlated source side information are considered. For several multiuser channel models necessary and sufficient conditions for optim...
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source and channel coding over multiuser channels in which receivers have access to correlated source side information are considered. For several multiuser channel models necessary and sufficient conditions for optimal separation of the source and channel codes are obtained. In particular, the multiple-access channel, the compound multiple-access channel, the interference channel, and the two-way channel with correlated sources and correlated receiver side information are considered, and the optimality of separation is shown to hold for certain source and side information structures. Interestingly, the optimal separate source and channel codes identified for these models are not necessarily the optimal codes for the underlying sourcecoding or the channelcoding problems. In other words, while separation of the source and channel codes is optimal, the nature of these optimal codes is impacted by the joint design criterion.
In this paper, delay-limited transmission of quasi-stationary sources over block fading channels is considered. Considering distortion outage probability as the performance measure, two source and channel coding schem...
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In this paper, delay-limited transmission of quasi-stationary sources over block fading channels is considered. Considering distortion outage probability as the performance measure, two source and channel coding schemes with power adaptive transmission are presented. The first one is optimized for fixed rate transmission, and hence enjoys simplicity of implementation. The second one is a high performance scheme, which also benefits from optimized rate adaptation with respect to source and channel states. In high SNR regime, the performance scaling laws in terms of outage distortion exponent and asymptotic outage distortion gain are derived, where two schemes with fixed transmission power and adaptive or optimized fixed rates are considered as benchmarks for comparisons. Various analytical and numerical results are provided which demonstrate a superior performance for source and channel optimized rate and power adaptive scheme. It is also observed that from a distortion outage perspective, the fixed rate adaptive power scheme substantially outperforms an adaptive rate fixed power scheme for delay-limited transmission of quasi-stationary sources over wireless block fading channels. The effect of the characteristics of the quasi-stationary source on performance, and the implication of the results for transmission of stationary sources are also investigated.
Virtual reality (VR) provides users extraordinary viewing experience and draws more and more attentions from both industry and academia. In this paper, we propose JET: Joint source and channel coding for Error resilie...
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Virtual reality (VR) provides users extraordinary viewing experience and draws more and more attentions from both industry and academia. In this paper, we propose JET: Joint source and channel coding for Error resilient virtual reality video wireless Transmission, where we jointly investigate how to conquer the problem of source video's huge size, how to efficiently satisfy a user's view switch request and how to handle packet loss. Specifically, we first divide a VR video into smaller video tiles. Upon a user's view switch request, the tiles corresponding to the part that the user is requesting, referred to as the field of view (FoV), and the part that the user may switch to before new video can be received, are delivered over a wireless network. We consider unequal error protection (UEP) for FoV and the rest part and formulate the inherent error resilient VR video transmission problem into a joint source and channel coding problem. In particular, we optimize the tile partition, quantization parameter and Forward Error Correction (FEC) packet allocation to maximize a user's received video quality. We also propose a low-complexity heuristic algorithm to solve this optimization problem. Extensive simulations are conducted and simulation results verify the superior performance. (C) 2018 Elsevier B.V. All rights reserved.
Turbo codes are a practical solution for achieving large coding gains. In this letter we present a new turbo coding scheme where the component codes are convolutional codes (CC's) over the ring of integers module ...
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Turbo codes are a practical solution for achieving large coding gains. In this letter we present a new turbo coding scheme where the component codes are convolutional codes (CC's) over the ring of integers module M, with M being the alphabet size of the source encoder. The a priori knowledge of the source statistics is used during the iterative decoding procedure for improved decoder performance. As an example of application, we examine differential pulse code modulation (DPCM)-encoded image transmission.
Cooperative techniques form a new wireless communication paradigm in which terminals help each other in relaying information to combat the random fading and to provide diversity in radio channels. Past work has focuse...
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ISBN:
(纸本)0780389387
Cooperative techniques form a new wireless communication paradigm in which terminals help each other in relaying information to combat the random fading and to provide diversity in radio channels. Past work has focused on improving channel reliability through cooperation. We propose to jointly allocate bits among sourcecoding, channelcoding and cooperation to minimize the expected source distortion. Recognizing that not all source bits are equal, we further propose to protect the more important bits through user cooperation. To evaluate the gain of layered cooperation, we simulate four modes of communications that differ in their error protection strategy (equal vs. layered, with vs. without cooperation) with a practical channel coder, and show that, for i.i.d. Gaussian sources, layered cooperation can achieve significant performance gains over non-layered/non-cooperative communication. We also carry out an information theoretic analysis illustrating fundamental benefits of layered cooperation.
We consider the progressive transmission of a lossy source across a power constrained Gaussian channel using binary phase-shift keying modulation. Under the theoretical assumptions of infinite bandwidth, arbitrarily c...
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We consider the progressive transmission of a lossy source across a power constrained Gaussian channel using binary phase-shift keying modulation. Under the theoretical assumptions of infinite bandwidth, arbitrarily complex channelcoding, and lossless transmission, we derive the optimal channel code rate and the optimal energy allocation per transmitted bit. Under the practical assumptions of a low complexity class of algebraic channel codes and progressive image coding, we numerically optimize the choice of channel code rate and the energy, per bit allocation. This model provides an additional degree of freedom with respect to previously proposed schemes, and can achieve a higher performance for sources such as images. It also allows one to control bandwidth expansion or reduction.
A new class of spherical codes called wrapped spherical codes is constructed by ''wrapping'' any sphere packing Lambda in Euclidean space onto a finite subset of the unit sphere in one higher dimension...
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A new class of spherical codes called wrapped spherical codes is constructed by ''wrapping'' any sphere packing Lambda in Euclidean space onto a finite subset of the unit sphere in one higher dimension. The mapping preserves much of the structure of Lambda, and unlike previously proposed maps, the density of wrapped spherical codes approaches the density of Lambda as the minimum distance approaches zero. We show that this implies that the asymptotically maximum spherical coding density is achieved by wrapped spherical codes whenever Lambda is the densest possible sphere packing.
New spherical codes called laminated spherical codes are constructed in dimensions 2-49 using a technique similar to the construction of laminated lattices. Each spherical code is recursively constructed from existing...
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New spherical codes called laminated spherical codes are constructed in dimensions 2-49 using a technique similar to the construction of laminated lattices. Each spherical code is recursively constructed from existing spherical codes in one lower dimension. Laminated spherical codes outperform the best known spherical codes in the minimum distance sense for many code sizes. The density of a laminated spherical code approaches the density of the laminated lattice in one lower dimension, as the minimum distance approaches zero. In particular, the three-dimensional laminated spherical code is asymptotically optimal, in the sense that its density approaches the Fejes Toth upper bound as the minimum distance approaches zero. Laminated spherical codes perform asymptotically as well as wrapped spherical codes in those dimensions where laminated lattices are optimal sphere packings.
Achievable distortion bounds are derived for the cascade of structured families of binary linear channel codes and binary lattice vector quantizers. it is known that for the cascade of asymptotically good channel code...
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Achievable distortion bounds are derived for the cascade of structured families of binary linear channel codes and binary lattice vector quantizers. it is known that for the cascade of asymptotically good channel codes and asymptotically good vector quantizers the end-to-end distortion decays to zero exponentially fast as a function of the overall transmission rate, and is achieved by choosing a channel code rate that is independent of the overall transmission rate. We show that for certain families of practical channel codes and binary lattice vector quantizers, the overall distortion can be made to decay to zero exponentially fast as a function of the square root of transmission rate. This is achieved by carefully choosing a channel code rate that decays to zero as the transmission rate grows. Explicit channel code rate schedules are obtained for several well-known families of channel codes.
We determine analytic expressions for the performance of some low-complexity combined source-channelcoding systems, The main tool used is the Hadamard transform, In particular, we obtain formulas for the average dist...
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We determine analytic expressions for the performance of some low-complexity combined source-channelcoding systems, The main tool used is the Hadamard transform, In particular, we obtain formulas for the average distortion of binary lattice vector quantization with affine index assignments, linear block channelcoding, and a binary-symmetric channel, The distortion formulas are specialized to nonredundant channel codes for a binary-symmetric channel, and then extended to affine index assignments on a binary-asymmetric channel, Various structured index assignments are compared. Our analytic formulas provide a computationally efficient method for determining the performance of various coding schemes, One interesting result shown is that for a uniform source and uniform quantizer, the Natural Binary Code is never optimal for a nonsymmetric channel, even though it is known to be optimal for a symmetric channel.
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