Results 11  20
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241
An extremal inequality motivated by multiterminal information theoretic problems
, 2006
"... We prove a new extremal inequality, motivated by the vector Gaussian broadcast channel and the distributed source coding with a single quadratic distortion constraint problem. As a corollary, this inequality yields a generalization of the classical vector entropypower inequality (EPI). As another c ..."
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Cited by 82 (5 self)
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We prove a new extremal inequality, motivated by the vector Gaussian broadcast channel and the distributed source coding with a single quadratic distortion constraint problem. As a corollary, this inequality yields a generalization of the classical vector entropypower inequality (EPI). As another corollary, this inequality sheds insight into maximizing the differential entropy of the sum of two jointly distributed random variables.
Gamal, “An outer bound to the capacity region of the broadcast channel
 IEEE Trans. Info. Theory
, 2007
"... Abstract — An outer bound to the capacity region of the tworeceiver discrete memoryless broadcast channel is given. The outer bound is tight for all cases where the capacity region is known. When specialized to the case of no common information, this outer bound is shown to be contained in the Körn ..."
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Cited by 75 (14 self)
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Abstract — An outer bound to the capacity region of the tworeceiver discrete memoryless broadcast channel is given. The outer bound is tight for all cases where the capacity region is known. When specialized to the case of no common information, this outer bound is shown to be contained in the KörnerMarton outer bound. This containment is shown to be strict for the binary skewsymmetric broadcast channel. Thus, this outer bound is in general tighter than all other known outer bounds on the discrete memoryless broadcast channel. 1.
Broadcast Channels with Cooperating Decoders
, 2006
"... We consider the problem of communicating over the general discrete memoryless broadcast channel (BC) with partially cooperating receivers. In our setup, receivers are able to exchange messages over noiseless conference links of finite capacities, prior to decoding the messages sent from the transmi ..."
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Cited by 59 (4 self)
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We consider the problem of communicating over the general discrete memoryless broadcast channel (BC) with partially cooperating receivers. In our setup, receivers are able to exchange messages over noiseless conference links of finite capacities, prior to decoding the messages sent from the transmitter. In this paper we formulate the general problem of broadcast with cooperation. We first find the capacity region for the case where the BC is physically degraded. Then, we give achievability results for the general broadcast channel, for both the two independent messages case and the single common message case.
Signaling over mimo multibase systems: Combination of multiaccess and broadcast schemes
 IN IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY
, 2006
"... A new structure for multibase systems is studied in which each user receives data from two nearby base stations, rather than only from the strongest one. This system can be considered as a combination of broadcast and multiaccess channels. By taking advantages of both perspectives, an achievable ..."
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Cited by 50 (4 self)
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A new structure for multibase systems is studied in which each user receives data from two nearby base stations, rather than only from the strongest one. This system can be considered as a combination of broadcast and multiaccess channels. By taking advantages of both perspectives, an achievable rate region for a discrete memoryless channel modeled by Pr(y1,y2x1,x2) is derived. In this model, x1 and x2 represent the transmitted signals by the transmitter one and two, respectively, and y1 and y2 denote the received signals by the receiver one and two, respectively. In this derivation, it is assumed that each transmitter is unaware of the data of the other transmitter, and therefore x1 and x2 are independent. To investigate the advantage of this scheme, an efficient signaling method which works at a corner point of the achievable region for multipleantenna scenarios is developed. In the proposed scheme, each base station only requires the state information of the channels between the other base station and each user. In this paper, the signaling scheme is elaborated for the case that each transmitter/reciever is equipped with three antennas. It is proven that in such a scenario, the multiplexing gain of four is achievable, which outperforms any other conventional schemes.
On interference channels with generalized feedback
 In Proceedings of IEEE Int. Symp. on Inform. Theory, ISIT2007
, 2007
"... An Interference Channel with Generalized Feedback (IFCGF) is a model for a wireless network where several sourcedestination pairs compete for the same channel resources, and where the sources have the ability to sense the current channel activity. The signal overheard from the channel provides inf ..."
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Cited by 48 (8 self)
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An Interference Channel with Generalized Feedback (IFCGF) is a model for a wireless network where several sourcedestination pairs compete for the same channel resources, and where the sources have the ability to sense the current channel activity. The signal overheard from the channel provides information about the activity of the other users, and thus furnishes the basis for cooperation. In this twopart paper we study achievable strategies and outer bounds for a general IFCGF with two sourcedestination pairs. We then evaluate the proposed regions for the Gaussian channel. Part I: Achievable Region. We propose that the generalized feedback is used to gain knowledge about the message sent by the other user and then exploited in two ways: (a) to relay the messages that can be decoded at both destinations–thus realizing the gains of beamforming of a distributed multiantenna system–and (b) to hide the messages that can not be decoded at the nonintended destination–thus leveraging the interference “precancellation” property of dirtypapertype coding. We show that our achievable region generalizes several known achievable regions for IFCGF and that it reduces
Sum Capacity of the Multiple Antenna Gaussian Broadcast Channel And UplinkDownlink Duality
 IEEE Transactions on Information Theory
, 2002
"... We characterize the sum capacity of the multiple antenna Gaussian broadcast channel by showing that the existing inner bound of Marton and the existing upper bound of Sato are tight for this channel. We exploit an intimate fourway connection between the multiple antenna broadcast channel, the corre ..."
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Cited by 48 (4 self)
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We characterize the sum capacity of the multiple antenna Gaussian broadcast channel by showing that the existing inner bound of Marton and the existing upper bound of Sato are tight for this channel. We exploit an intimate fourway connection between the multiple antenna broadcast channel, the corresponding pointtopoint channel (where the receivers can cooperate), the multiple access channel (where the role of transmitters and receivers are reversed), and the corresponding pointtopoint channel (where the transmitters can cooperate).
Capacity with causal and noncausal side information  A Unified View
 IEEE Trans. Inf. Theory
, 2006
"... We identify the common underlying form of the capacity expression that is applicable to both cases where causal or noncausal side information is made available to the transmitter. Using this common form we find that for the single user channel, the multiple access channel, the degraded broadcast ch ..."
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Cited by 47 (3 self)
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We identify the common underlying form of the capacity expression that is applicable to both cases where causal or noncausal side information is made available to the transmitter. Using this common form we find that for the single user channel, the multiple access channel, the degraded broadcast channel, and the degraded relay channel, the sum capacity with causal and noncausal side information are identical when all the transmitter side information is also made available to all the receivers. A genieaided outerbound is developed that states that when a genie provides n bits of side information to a receiver the resulting capacity improvement can not be more than n bits. Combining these two results we are able to bound the relative capacity advantage of noncausal side information over causal side information for both single user as well as various multiple user communication scenarios. Applications of these capacity bounds are demonstrated through examples of random access channels. Interestingly, the capacity results indicate that the excessive MAC layer overheads common in present wireless systems may be avoided through coding across multiple access blocks. It is also shown that even one bit of side information at the transmitter can result in unbounded capacity improvement.
Communication via Decentralized Processing
, 2007
"... The problem of a nomadic terminal sending information to a remote destination via agents with lossless connections to the destination is investigated. Such a setting suits, e.g. access points of a wireless network where each access point is connected by a wire to a wirelinebased network. The Gaussi ..."
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Cited by 45 (4 self)
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The problem of a nomadic terminal sending information to a remote destination via agents with lossless connections to the destination is investigated. Such a setting suits, e.g. access points of a wireless network where each access point is connected by a wire to a wirelinebased network. The Gaussian codebook capacity for the case where the agents do not have any decoding ability is characterized for the Gaussian channel. This restriction is demonstrated to be severe, where allowing the nomadic transmitter to use other signaling improves the rate. For both general and degraded discrete memoryless channels, lower and upper bounds on the capacity are derived. An achievable rate with unrestricted agents, which are capable of decoding, is also given and then used to characterize the capacity for the deterministic channel.