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110
An algebraic approach to network coding
 IEEE/ACM Transactions on Networking
, 2003
"... Abstract—We take a new look at the issue of network capacity. It is shown that network coding is an essential ingredient in achieving the capacity of a network. Building on recent work by Li et al., who examined the network capacity of multicast networks, we extend the network coding framework to ar ..."
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Cited by 518 (89 self)
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Abstract—We take a new look at the issue of network capacity. It is shown that network coding is an essential ingredient in achieving the capacity of a network. Building on recent work by Li et al., who examined the network capacity of multicast networks, we extend the network coding framework to arbitrary networks and robust networking. For networks which are restricted to using linear network codes, we find necessary and sufficient conditions for the feasibility of any given set of connections over a given network. We also consider the problem of network recovery for nonergodic link failures. For the multicast setup we prove that there exist coding strategies that provide maximally robust networks and that do not require adaptation of the network interior to the failure pattern in question. The results are derived for both delayfree networks and networks with delays. Index Terms—Algebraic coding, network information theory, network robustness. I.
A Network Information Theory for Wireless Communication: Scaling Laws and Optimal Operation
 IEEE Transactions on Information Theory
, 2002
"... How much information can be carried over a wireless network with a multiplicity of nodes? What are the optimal strategies for information transmission and cooperation among the nodes? We obtain sharp information theoretic scaling laws under some conditions. ..."
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Cited by 272 (16 self)
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How much information can be carried over a wireless network with a multiplicity of nodes? What are the optimal strategies for information transmission and cooperation among the nodes? We obtain sharp information theoretic scaling laws under some conditions.
The effect upon channel capacity in wireless communications of perfect and imperfect knowledge of the channel
 IEEE Trans. Inf. Theory
, 2000
"... Abstract—We present a model for timevarying communication singleaccess and multipleaccess channels without feedback. We consider the difference between mutual information when the receiver knows the channel perfectly and mutual information when the receiver only has an estimate of the channel. We ..."
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Cited by 194 (4 self)
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Abstract—We present a model for timevarying communication singleaccess and multipleaccess channels without feedback. We consider the difference between mutual information when the receiver knows the channel perfectly and mutual information when the receiver only has an estimate of the channel. We relate the variance of the channel measurement error at the receiver to upper and lower bounds for this difference in mutual information. We illustrate the use of our bounds on a channel modeled by a Gauss–Markov process, measured by a pilot tone. We relate the rate of time variation of the channel to the loss in mutual information due to imperfect knowledge of the measured channel. Index Terms—Channel uncertainty, multipleaccess channels, mutual information, timevarying channels, wireless communications. I.
Iterative Waterfilling for Gaussian Vector Multiple Access Channels
 IEEE Transactions on Information Theory
, 2001
"... This paper characterizes the capacity region of a Gaussian multiple access channel with vector inputs and a vector output with or without intersymbol interference. The problem of finding the optimal input distribution is shown to be a convex programming problem, and an efficient numerical algorithm ..."
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Cited by 190 (11 self)
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This paper characterizes the capacity region of a Gaussian multiple access channel with vector inputs and a vector output with or without intersymbol interference. The problem of finding the optimal input distribution is shown to be a convex programming problem, and an efficient numerical algorithm is developed to evaluate the optimal transmit spectrum under the maximum sum data rate criterion. The numerical algorithm has an it#8 at#8 e wat#8filling int#j pret#4968 . It converges from any starting point and it reaches with in s per output dimension per transmission from the Kuser multiple access sum capacity af t#j just one it#4 at#49 . These results are also applicable to vector multiple access fading channels.
Multiaccess Fading Channels  Part I: Polymatroid Structure, Optimal Resource Allocation and Throughput Capacities
 IEEE Trans. Inform. Theory
"... In multiaccess wireless systems, dynamic allocation of resources such as transmit power, bandwidths, and rates is an important means to deal with the timevarying nature of the environment. In this twopart paper, we consider the problem of optimal resource allocation from an informationtheoretic p ..."
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Cited by 174 (9 self)
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In multiaccess wireless systems, dynamic allocation of resources such as transmit power, bandwidths, and rates is an important means to deal with the timevarying nature of the environment. In this twopart paper, we consider the problem of optimal resource allocation from an informationtheoretic point of view. We focus on the multiaccess fading channel with Gaussian noise, and define two notions of capacity depending on whether the traffic is delaysensitive or not. In part I, we characterize the throughput capacity region which contains the longterm achievable rates through the timevarying channel. We show that each point on the boundary of the region can be achieved by successive decoding. Moreover, the optimal rate and power allocations in each fading state can be explicitly obtained in a greedy manner. The solution can be viewed as the generalization of the waterfilling construction for singleuser channels to multiaccess channels with arbitrary number of users, and exploits the underlying polymatroid structure of the capacity region. In part II, we characterize a delaylimited capacity region and obtain analogous results.
Towards an Information Theory of Large Networks: An Achievable Rate Region
 IEEE Trans. Inform. Theory
, 2003
"... Abstract — We study communication networks of arbitrary size and topology and communicating over a general vector discrete memoryless channel. We propose an informationtheoretic constructive scheme for obtaining an achievable rate region in such networks. Many wellknown capacitydefining achievabl ..."
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Cited by 161 (9 self)
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Abstract — We study communication networks of arbitrary size and topology and communicating over a general vector discrete memoryless channel. We propose an informationtheoretic constructive scheme for obtaining an achievable rate region in such networks. Many wellknown capacitydefining achievable rate regions can be derived as special cases of the proposed scheme. A few such examples are the physically degraded and reverselydegraded relay channels, the Gaussian multipleaccess channel, and the Gaussian broadcast channel. The proposed scheme also leads to inner bounds for the multicast and allcast capacities. Applying the proposed scheme to a specific wireless network of nodes located in a region of unit area, we show that a transport capacity of ¡£ ¢ bitmeters/sec is feasible in a certain family of networks, as compared to the best possible transport capacity ¡£¢§ ¦ ¨ ¤ of bitmeters/sec in [16] where the receiver capabilities were limited. Even though the improvement is shown for a specific class of networks, a clear implication is that designing and employing more sophisticated multiuser coding schemes can provide sizable gains in at least some large wireless networks. Index Terms — Discrete memoryless channels, Gaussian channels, multiuser communications, network information theory,
Information Theory and Communication Networks: An Unconsummated Union
 IEEE Trans. Inform. Theory
, 1998
"... Information theory has not yet had a direct impact on networking, although there are similarities in concepts and methodologies that have consistently attracted the attention of researchers from both fields. In this paper, we review several topics that are related to communication networks and that ..."
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Cited by 133 (5 self)
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Information theory has not yet had a direct impact on networking, although there are similarities in concepts and methodologies that have consistently attracted the attention of researchers from both fields. In this paper, we review several topics that are related to communication networks and that have an information theoretic flavor, including multiaccess protocols, timing channels, effective bandwidth of bursty data sources, deterministic constraints on datastreams, queueing theory, and switching networks. Keywords Communication networks, multiaccess, effective bandwidth, switching I. INTRODUCTION Information theory is the conscience of the theory of communication; it has defined the "playing field" within which communication systems can be studied and understood. It has provided the spawning grounds for the fields of coding, compression, encryption, detection, and modulation and it has enabled the design and evaluation of systems whose performance is pushing the limits of wha...
Multiple access channels with arbitrarily correlated sources
 IEEE Transactions on Information Theory
, 1980
"... AbsrmcrLet {(q, r$)}#L * be a source of independealt identicauy distributed (i.i.d.) disc&e random variables with joint probability mass function p(u,o) and common part wf(u)=g(u) in the sense of Witsenbawn, Gacs, and Kkner. It is shown that such a source can be sent with arbitrarily small probabi ..."
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Cited by 115 (2 self)
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AbsrmcrLet {(q, r$)}#L * be a source of independealt identicauy distributed (i.i.d.) disc&e random variables with joint probability mass function p(u,o) and common part wf(u)=g(u) in the sense of Witsenbawn, Gacs, and Kkner. It is shown that such a source can be sent with arbitrarily small probability of error over a multiple access ChaMel (MAC) {Xl X~*9%P(Yl~,, X,)>> with allowed codes {q(u), x2(w)] if there exist probability mass functions P(S),P(X,lS, U),P(X,lS9 u)9 s’dl that H(UIV)<Z(X,;YIX,,~,S), H(VIU)<Z(X*;YIX,,U,S),
The Method of Types
, 1998
"... The method of types is one of the key technical tools in Shannon Theory, and this tool is valuable also in other fields. In this paper, some key applications will be presented in sufficient detail enabling an interested nonspecialist to gain a working knowledge of the method, and a wide selection of ..."
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Cited by 95 (0 self)
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The method of types is one of the key technical tools in Shannon Theory, and this tool is valuable also in other fields. In this paper, some key applications will be presented in sufficient detail enabling an interested nonspecialist to gain a working knowledge of the method, and a wide selection of further applications will be surveyed. These range from hypothesis testing and large deviations theory through error exponents for discrete memoryless channels and capacity of arbitrarily varying channels to multiuser problems. While the method of types is suitable primarily for discrete memoryless models, its extensions to certain models with memory will also be discussed. Index TermsArbitrarily varying channels, choice of decoder, counting approach, error exponents, extended type concepts, hypothesis testing, large deviations, multiuser problems, universal coding. I.