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55
Gaussian interference network: Sum capacity . . .
, 2008
"... Establishing the capacity region of a Gaussian interference network is an open problem in information theory. Recent progress on this problem has led to the characterization of the capacity region of a general two user Gaussian interference channel within one bit. In this paper, we develop new, impr ..."
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Cited by 133 (5 self)
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Establishing the capacity region of a Gaussian interference network is an open problem in information theory. Recent progress on this problem has led to the characterization of the capacity region of a general two user Gaussian interference channel within one bit. In this paper, we develop new, improved outer bounds on the capacity region. Using these bounds, we show that treating interference as noise achieves the sum capacity of the two user Gaussian interference channel in a low interference regime, where the interference parameters are below certain thresholds. We then generalize our techniques and results to Gaussian interference networks with more than two users. In particular, we demonstrate that the total interference threshold, below which treating interference as noise achieves the sum capacity, increases with the number of users.
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 (9 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
Capacity of cognitive interference channels with and without secrecy,” submitted for publication
"... Abstract—Like the conventional twouser interference channel, the cognitive interference channel consists of two transmitters whose signals interfere at two receivers. It is assumed that there is a common message (message 1) known to both transmitters, and an additional independent message (message ..."
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Cited by 39 (6 self)
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Abstract—Like the conventional twouser interference channel, the cognitive interference channel consists of two transmitters whose signals interfere at two receivers. It is assumed that there is a common message (message 1) known to both transmitters, and an additional independent message (message 2) known only to the cognitive transmitter (transmitter 2). The cognitive receiver (receiver 2) needs to decode messages 1 and 2, while the noncognitive receiver (receiver 1) should decode only message 1. Furthermore, message 2 is assumed to be a confidential message which needs to be kept as secret as possible from receiver 1, which is viewed as an eavesdropper with regard to message 2. The level of secrecy is measured by the equivocation rate. In this paper, a singleletter expression for the capacityequivocation region of the discrete memoryless cognitive interference channel is obtained. The capacityequivocation region for the Gaussian cognitive interference channel is also obtained explicitly. Moreover, particularizing the capacityequivocation region to the case without a secrecy constraint, the capacity region for the twouser cognitive interference channel is obtained, by providing a converse theorem. Index Terms—Capacityequivocation region, cognitive communication, confidential messages, interference channel, rate splitting, secrecy capacity region. I.
The degrees of freedom region and interference alignment for the MIMO interference channel with delayed CSI,” 2011. [Online]. Available: http://arxiv.org/abs/1101.5809
"... The degrees of freedom (DoF) region of the 2user multipleantenna or MIMO (multipleinput, multipleoutput) interference channel (IC) is studied under fast fading and the assumption of delayed channel state information (CSI) wherein all terminals know all (or certain) channel matrices perfectly, bu ..."
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Cited by 39 (5 self)
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The degrees of freedom (DoF) region of the 2user multipleantenna or MIMO (multipleinput, multipleoutput) interference channel (IC) is studied under fast fading and the assumption of delayed channel state information (CSI) wherein all terminals know all (or certain) channel matrices perfectly, but with a delay, and each receiver in addition knows its own incoming channels instantaneously. The general MIMO IC is considered with an arbitrary number of antennas at each of the four terminals. Dividing it into several classes depending on the relation between the numbers of antennas at the four terminals, the fundamental DoF regions are characterized under the delayed CSI assumption for all possible values of number of antennas at the four terminals. In particular, an outer bound on the DoF region of the general MIMO IC is derived. This bound is then shown to be tight for all MIMO ICs by developing interference alignment based achievability schemes for each class. A comparison of these DoF regions under the delayed CSI assumption is made with those of the idealistic ‘perfect CSI’ assumption where perfect and instantaneous CSI is available at all terminals on the one hand and with the DoF regions of the conservative ‘no CSI ’ assumption on the other, where CSI is available at the receivers but not at all at the transmitters.
Capacity Regions and SumRate Capacities of Vector Gaussian Interference Channels
, 2009
"... The capacity regions of vector, or multipleinput multipleoutput, Gaussian interference channels are established for very strong interference and aligned strong interference. Furthermore, the sumrate capacities are established for Z interference, noisy interference, and mixed (aligned weak/interme ..."
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Cited by 33 (4 self)
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The capacity regions of vector, or multipleinput multipleoutput, Gaussian interference channels are established for very strong interference and aligned strong interference. Furthermore, the sumrate capacities are established for Z interference, noisy interference, and mixed (aligned weak/intermediate and aligned strong) interference. These results generalize known results for scalar Gaussian interference channels.
Degrees of Freedom of the K User M × N MIMO Interference Channel
, 809
"... We provide innerbound and outerbound for the total number of degrees of freedom of the K user multiple input multiple output (MIMO) Gaussian interference channel with M antennas at each transmitter and N antennas at each receiver if the channel coefficients are timevarying and drawn from a continuo ..."
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Cited by 32 (4 self)
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We provide innerbound and outerbound for the total number of degrees of freedom of the K user multiple input multiple output (MIMO) Gaussian interference channel with M antennas at each transmitter and N antennas at each receiver if the channel coefficients are timevarying and drawn from a continuous distribution. The bounds are tight when the ratio max(M,N) min(M,N) = R is equal to an integer. For this case, we show that the total number of degrees of freedom is equal to min(M, N)K if K ≤ R and min(M, N) R R+1K if K> R. Achievability is based on interference alignment. We also provide examples where using interference alignment combined with zero forcing can achieve more degrees of freedom than merely zero forcing for some MIMO interference channels with constant channel coefficients. 2 I.
Sum Capacity of MIMO Interference Channels in the Low Interference Regime
, 909
"... Using Gaussian inputs and treating interference as noise at the receivers has recently been shown to be sum capacity achieving for the twouser singleinput singleoutput (SISO) Gaussian interference channel in a low interference regime, where the interference levels are below certain thresholds. In ..."
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Cited by 29 (2 self)
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Using Gaussian inputs and treating interference as noise at the receivers has recently been shown to be sum capacity achieving for the twouser singleinput singleoutput (SISO) Gaussian interference channel in a low interference regime, where the interference levels are below certain thresholds. In this paper, such a low interference regime is characterized for multipleinput multipleoutput (MIMO) Gaussian interference channels. Conditions are provided on the direct and cross channel gain matrices under which using Gaussian inputs and treating interference as noise at the receivers is sum capacity achieving. For the special cases of the symmetric multipleinput singleoutput (MISO) and singleinput multipleoutput (SIMO) Gaussian interference channels, more explicit expressions for the low interference regime are derived. In particular, the threshold on the interference levels that characterize low interference regime is related to the input SNR and the angle between the direct and cross channel gain vectors. It is shown that the low interference regime can be quite significant for MIMO interference channels, with the low interference threshold being at least as large as the sine of the angle between the direct and cross channel gain vectors for the MISO and SIMO cases. I.
An outer bound region for interference channels with generalized feedback
 in Information Theory and Applications Workshop (ITA), 2010, Feb.2010,pp.1–5
"... (IFCGF) are a model for wireless communication systems with source cooperation. GF enables to enlarge the achievable rate region with respect to the noncooperative IFC without requiring an increase in system resources. This paper develops an outer bound region on the capacity of general IFCGF and ..."
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Cited by 19 (7 self)
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(IFCGF) are a model for wireless communication systems with source cooperation. GF enables to enlarge the achievable rate region with respect to the noncooperative IFC without requiring an increase in system resources. This paper develops an outer bound region on the capacity of general IFCGF and then tighten it further for a class of semideterministic IFCGF that include the “high SNR approximation ” of the Gaussian channel and the Gaussian channel as special cases.
Capacity Regions and Bounds for a Class of Zinterference Channels
"... We define a class of Zinterference channels for which we obtain a new upper bound on the capacity region. The bound exploits a technique first introduced by Korner and Marton. A channel in this class has the property that, for the transmitterreceiver pair that suffers from interference, the condit ..."
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Cited by 14 (6 self)
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We define a class of Zinterference channels for which we obtain a new upper bound on the capacity region. The bound exploits a technique first introduced by Korner and Marton. A channel in this class has the property that, for the transmitterreceiver pair that suffers from interference, the conditional output entropy at the receiver is invariant with respect to the transmitted codewords. We compare the new capacity region upper bound with the Han/Kobayashi achievable rate region for interference channels. This comparison shows that our bound is tight in some cases, thereby yielding specific points on the capacity region as well as sum capacity for certain Zinterference channels. In particular, this result can be used as an alternate method to obtain sum capacity of Gaussian Zinterference channels. We then apply an additional restriction on our channel class: the transmitterreceiver pair that suffers from interference achieves its maximum output entropy with a single input distribution irrespective of the interference distribution. For these channels we show that our new capacity region upper bound coincides with the Han/Kobayashi achievable rate region, which is therefore capacityachieving. In particular, for these channels superposition encoding with partial decoding is shown to be optimal and a singleletter characterization for the capacity region is obtained.