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22
Capacity theorems for the multipleaccess relay channel
 In Allerton Conference on Communications, Control and Computing
, 2004
"... Outer bounds for the discrete memoryless multipleaccess relay channel (MARC) are obtained that exploit the causal relationship between the source and relay inputs. A novel offset encoding technique that facilitates window decoding at the destination is presented for a decodeandforward strategy, w ..."
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Cited by 52 (3 self)
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Outer bounds for the discrete memoryless multipleaccess relay channel (MARC) are obtained that exploit the causal relationship between the source and relay inputs. A novel offset encoding technique that facilitates window decoding at the destination is presented for a decodeandforward strategy, where the relay decodes the source messages before forwarding to the destination. A compressandforward strategy for the MARC and an amplifyandforward strategy for the Gaussian MARC are also presented. 1
Fifty Years of Shannon Theory
, 1998
"... A brief chronicle is given of the historical development of the central problems in the theory of fundamental limits of data compression and reliable communication. ..."
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Cited by 50 (1 self)
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A brief chronicle is given of the historical development of the central problems in the theory of fundamental limits of data compression and reliable communication.
Source and Channel Coding for Correlated Sources Over Multiuser Channels
, 2009
"... 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 mul ..."
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Cited by 26 (4 self)
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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 multipleaccess channel, the compound multipleaccess channel, the interference channel, and the twoway 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 source coding or the channel coding 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.
An outer bound for a multiuser twoway channel
 in Annual Allerton Conference on Communication, control and Computing
, 2006
"... Abstract — Most networks are twoway in nature, i.e., senders are also receivers. However, little is known about twoway networks except for the simplest twoway channel between two nodes, first proposed and studied by Shannon in 1961. In this paper, we continue our study of a threenode multiuser t ..."
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Cited by 5 (1 self)
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Abstract — Most networks are twoway in nature, i.e., senders are also receivers. However, little is known about twoway networks except for the simplest twoway channel between two nodes, first proposed and studied by Shannon in 1961. In this paper, we continue our study of a threenode multiuser twoway channel first proposed by the authors in [1]. Our main result is an outer bound on the capacity region of the threenode network where each node operates in halfduplex mode. The key challenge in deriving the outer bound stems from the infinite Markov chain structure induced by the implicit feedback in encoding at each node. We show that the outer bound reduces to wellknown results in multiple access and broadcast channels in several special cases. I.
Multiuser twoway deterministic modulo 2 adder channels – when adaptation is useless
 in Proc. Allerton Conf. Commun., Control and Comp
, 2011
"... Abstract—In twoway channels nodes are both sources and destinations of messages, allowing them to “adapt ” or “interact” in the sense that their next channel input may be a function of their past received signals. This “adaptation ” and how to best exploit it lies at the heart of twoway communicat ..."
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Cited by 3 (3 self)
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Abstract—In twoway channels nodes are both sources and destinations of messages, allowing them to “adapt ” or “interact” in the sense that their next channel input may be a function of their past received signals. This “adaptation ” and how to best exploit it lies at the heart of twoway communication problems, rendering them particularly complex and challenging. It would be useful to know when adaptation is not beneficial from a capacity perspective. Certain examples exist: it is known that for the pointtopoint twoway modulo 2 adder channel, and the pointtopoint Gaussian twoway channel, adaptation does not increase capacity. In this work we show that the same is true for certain classes of deterministic multiuser twoway channels. In particular, we consider a class of multiuser twoway modulo 2 adder channels, which include the twoway modulo 2 adder MAC/BC channel, the twoway modulo 2 adder interference channel, and the twoway modulo 2 adder Z channel. For all three channel models we obtain the capacity region, which may be achieved using simple timesharing. I.
An Outer Bound Region for the Parallel Twoway Channel with Interference
"... Abstract—The classical interference channel models the communication limits of two independent, interfering streams of oneway data. In this paper we extend the classical interference channel model to a new channel model in which two streams of twoway data interfere with each other. In the absence ..."
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Cited by 3 (3 self)
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Abstract—The classical interference channel models the communication limits of two independent, interfering streams of oneway data. In this paper we extend the classical interference channel model to a new channel model in which two streams of twoway data interfere with each other. In the absence of interference, this model would result in two parallel twoway channels (a four node channel); in the presence of interference it encompasses twoway, interference, and cooperation tradeoffs. The discrete memoryless “parallel twoway channel with interference ” is considered, in which each of the four nodes is the source of one message, the receiver of another, and experiences interference from another in addition to its desired message. The nodes may adapt their transmissions to the past received signals in a fully twoway fashion. We present an outer bound to the four dimensional capacity region which utilizes auxiliary random variables to constrain the input distributions and comment on its relationship to existing outer bounds for related channels. I.
Twoway quantum communication channels
, 2005
"... We consider communication between two parties using a bipartite quantum operation, which constitutes the most general quantum mechanical model of twoparty communication. We primarily focus on the simultaneous forward and backward communication of classical messages. For the case in which the two pa ..."
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We consider communication between two parties using a bipartite quantum operation, which constitutes the most general quantum mechanical model of twoparty communication. We primarily focus on the simultaneous forward and backward communication of classical messages. For the case in which the two parties share unlimited prior entanglement, we give inner and outer bounds on the achievable rate region that generalize classical results due to Shannon. In particular, using a protocol of Bennett, Harrow, Leung, and Smolin, we give a oneshot expression in terms of the Holevo information for the entanglementassisted oneway capacity of a twoway quantum channel. As applications, we rederive two known additivity results for oneway channel capacities: the entanglementassisted capacity of a general oneway channel, and the unassisted capacity of an entanglementbreaking oneway channel. 1.
Outer Bounds for MultipleAccess Channels With Feedback Using Dependence Balance
, 2009
"... We use the idea of dependence balance to obtain a new outer bound for the capacity region of the discrete memoryless multipleaccess channel with noiseless feedback (MACFB). We consider a binary additive noisy MACFB whose feedback capacity is not known. The binary additive noisy MAC considered in ..."
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Cited by 1 (0 self)
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We use the idea of dependence balance to obtain a new outer bound for the capacity region of the discrete memoryless multipleaccess channel with noiseless feedback (MACFB). We consider a binary additive noisy MACFB whose feedback capacity is not known. The binary additive noisy MAC considered in this paper can be viewed as the discrete counterpart of the Gaussian MACFB. Ozarow established that the capacity region of the twouser Gaussian MACFB is given by the cutset bound. Our result shows that for the discrete version of the channel considered by Ozarow, this is not the case. Direct evaluation of our outer bound is intractable due to an involved auxiliary random variable whose large cardinality prohibits an exhaustive search. We overcome this difficulty by using a composite function and its properties to explicitly evaluate our outer bound. Our outer bound is strictly less than the cutset bound at all points on the capacity region where feedback increases capacity. In addition, we explicitly evaluate the Cover–Leung achievable rate region for the binary additive noisy MACFB in consideration. Furthermore, using the tools developed for the evaluation of our outer bound, we also explicitly characterize the boundary of the feedback capacity region of the binary erasure MAC, for which the Cover–Leung achievable rate region is known to be tight. This last result confirms that the feedback strategies developed by Kramer for the binary erasure MAC are capacity achieving.
1Twoway Networks: when Adaptation is Useless
"... Most wireless communication networks are twoway, where nodes act as both sources and destinations of messages. This allows for “adaptation ” at or “interaction ” between the nodes – a node’s channel inputs may be functions of its message(s) and previously received signals, in contrast to feedbackf ..."
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Most wireless communication networks are twoway, where nodes act as both sources and destinations of messages. This allows for “adaptation ” at or “interaction ” between the nodes – a node’s channel inputs may be functions of its message(s) and previously received signals, in contrast to feedbackfree oneway channels where inputs are functions of messages only. How to best adapt, or cooperate, is key to twoway communication, rendering it complex and challenging. However, examples exist of channels where adaptation is not beneficial from a capacity perspective; it is known that for the pointtopoint twoway modulo 2 adder and Gaussian channels, adaptation does not increase capacity. We ask whether analogous results hold for several multiuser twoway networks. We first consider deterministic twoway channel models: the binary modulo2 addition channel and a generalization of this, and the linear deterministic channel which models Gaussian channels at high SNR. For these deterministic models we obtain the capacity region for the twoway multiple access/broadcast channel, the twoway Z channel and the twoway interference channel (under certain “partial ” adaptation constraints in some regimes). We permit all nodes to adapt their channel inputs to past outputs (except for portions of the linear highSNR twoway interference channel where we only permit 2 of the 4 nodes to fully adapt). However, we show that this adaptation is useless from a capacity region perspective. That is, the twoway fully or partially adaptive capacity region consists
Common Randomness and Secret Key Capacities of Twoway Channels
"... Abstract. Common Randomness Generation (CRG) and Secret Key Establishment (SKE) are fundamental primitives that are used in informationtheoretic coding and cryptography. We study these two problems over the twoway channel model of communication, introduced by Shannon. In this model, the common ran ..."
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Abstract. Common Randomness Generation (CRG) and Secret Key Establishment (SKE) are fundamental primitives that are used in informationtheoretic coding and cryptography. We study these two problems over the twoway channel model of communication, introduced by Shannon. In this model, the common randomness (CK) capacity is defined as the maximum number of random bits per channel use that the two parties can generate. The secret key (SK) capacity is defined similarly when the random bits are also required to be secure against a passive adversary. We provide lower bounds on the two capacities. These lower bounds are tighter than those one might derive based on the previously known results. We prove our lower bounds by proposing a tworound, twolevel coding construction over the twoway channel. We show that the lower bound on the common randomness capacity can also be achieved using a simple interactive channel coding (ICC) method. We furthermore provide upper bounds on these capacities and show that the lower and the upper bounds coincide when the twoway channel consists of two independent (physically degraded) oneway channels. We apply the results to the case where the channels are binary symmetric.