Results 1 
6 of
6
Nonasymptotic Achievability Bounds in Multiuser Information Theory
"... Invoking random coding, but not typical sequences, we give nonasymptotic achievability results for the major setups in multiuser information theory. No limitations, such as memorylessness or discreteness, on sources/channels are imposed. All the bounds given are powerful enough to yield the constru ..."
Abstract

Cited by 14 (0 self)
 Add to MetaCart
Invoking random coding, but not typical sequences, we give nonasymptotic achievability results for the major setups in multiuser information theory. No limitations, such as memorylessness or discreteness, on sources/channels are imposed. All the bounds given are powerful enough to yield the constructive side of the (asymptotic) capacity regions in the memoryless case. The approach relies on simple nonasymptotic counterparts of the packing and covering lemmas conventionally used in conjunction with the typical sequence approach. Index Terms—Shannon theory, achievability, finite blocklength regime, random coding, multipleaccess channels, WynerZiv compression, broadcast channels, data transmission with encoder side information, almostlossless compression with a helper.
NonAsymptotic and SecondOrder Achievability Bounds for Source Coding With SideInformation
"... We present a novel achievability bound for the WynerAhlswedeKörner (WAK) problem of lossless source coding with ratelimited sideinformation. This bound is proved using ideas from channel simulation and channel resolvability. The bound improves on all previous nonasymptotic bounds on the error ..."
Abstract

Cited by 11 (6 self)
 Add to MetaCart
We present a novel achievability bound for the WynerAhlswedeKörner (WAK) problem of lossless source coding with ratelimited sideinformation. This bound is proved using ideas from channel simulation and channel resolvability. The bound improves on all previous nonasymptotic bounds on the error probability of the WAK problem. We also present achievable secondorder coding rates by applying the multidimensional BerryEssèen theorem to our new nonasymptotic bound.
A FiniteBlocklength Perspective on Gaussian MultiAccess Channels
, 2014
"... Motivated by the growing application of wireless multiaccess networks with stringent delay constraints, we investigate the Gaussian multiple access channel (MAC) in the finite blocklength regime. Building upon information spectrum concepts, we develop several nonasymptotic inner bounds on channel ..."
Abstract

Cited by 8 (0 self)
 Add to MetaCart
Motivated by the growing application of wireless multiaccess networks with stringent delay constraints, we investigate the Gaussian multiple access channel (MAC) in the finite blocklength regime. Building upon information spectrum concepts, we develop several nonasymptotic inner bounds on channel coding rates over the Gaussian MAC with a given finite blocklength, positive average error probability, and maximal power constraints. Employing Central Limit Theorem (CLT) approximations, we also obtain achievable secondorder coding rates for the Gaussian MAC based on an explicit expression for its dispersion matrix. We observe that, unlike the pentagon shape of the asymptotic capacity region, the secondorder region has a curved shape with no sharp corners. A main emphasis of the paper is to provide a new perspective on the procedure of handling input cost constraints for tight achievability proofs. Contrary to the complicated achievability techniques in the literature, we show that with a proper choice of input distribution, tight bounds can be achieved via the standard random coding argument and a modified typicality decoding. In particular, we prove that codebooks generated randomly according to independent uniform distributions on the respective “power shells ” perform far better than both independent and identically distributed (i.i.d.) Gaussian inputs and TDMA with power control. Interestingly, analogous to an error exponent result of Gallager, the resulting achievable region lies roughly halfway between that of the i.i.d. Gaussian inputs and that of a hypothetical “sumpower shell” input. However, dealing with such a noni.i.d. input requires additional analysis such as a new change of measure technique and application of a BerryEsseen CLT for functions of random variables.
SecondOrder Asymptotics for the Gaussian MAC with Degraded Message Sets
"... This paper studies the secondorder asymptotics of the Gaussian multipleaccess channel with degraded message sets. For a fixed average error probability ε ∈ (0, 1) and an arbitrary point on the boundary of the capacity region, we characterize the speed of convergence of rate pairs that converge to ..."
Abstract

Cited by 7 (7 self)
 Add to MetaCart
This paper studies the secondorder asymptotics of the Gaussian multipleaccess channel with degraded message sets. For a fixed average error probability ε ∈ (0, 1) and an arbitrary point on the boundary of the capacity region, we characterize the speed of convergence of rate pairs that converge to that point for codes that have asymptotic error probability no larger than ε. We do so by elucidating the relationship between global and local notions of secondorder asymptotics.
A Random Coding Approach to Gaussian Multiple Access Channels with Finite Blocklength
"... Abstract — Contrary to the common use of random coding and typicality decoding for the achievability proofs in information theory, the tightest achievable rates for pointtopoint Gaussian channels build either on geometric arguments or composite hypothesis testing, for which direct generalization t ..."
Abstract

Cited by 6 (1 self)
 Add to MetaCart
(Show Context)
Abstract — Contrary to the common use of random coding and typicality decoding for the achievability proofs in information theory, the tightest achievable rates for pointtopoint Gaussian channels build either on geometric arguments or composite hypothesis testing, for which direct generalization to multiuser settings appears challenging. In this paper, we provide a new perspective on the procedure of handling input cost constraints for tight achievability results. In particular, we show with a proper choice of input distribution and using a change of measure technique, tight bounds can be achieved via the common random coding argument and a modified typicality decoding. It is observed that a codebook generated randomly according to a uniform distribution on the “power shell ” is optimal, at least up to the second order. Such insights are then extended to a Gaussian multiple access channel, for which independent uniform distributions on power shells are shown to be very close to optimal, at least up to second order. I.
SecondOrder Rate Region of ConstantComposition Codes for the MultipleAccess Channel
, 2013
"... This paper presents an achievable secondorder rate region for the discrete memoryless multipleaccess channel. The result is obtained using a randomcoding ensemble in which each user’s codebook contains codewords of a fixed composition. The improvement of the secondorder rate region over existing ..."
Abstract
 Add to MetaCart
This paper presents an achievable secondorder rate region for the discrete memoryless multipleaccess channel. The result is obtained using a randomcoding ensemble in which each user’s codebook contains codewords of a fixed composition. The improvement of the secondorder rate region over existing ones is demonstrated both analytically and numerically. Finally, an achievable secondorder rate region for the Gaussian multipleaccess channel is derived via an increasingly fine quantization of the input.