Degrees of Freedom for the MIMO Interference Channel

Jafar, Syed A.; Fakhereddin, M.J.

doi:10.1109/tit.2007.899557

Cited by 473 publications

(494 citation statements)

References 14 publications

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“…From Lemma 1, we know that the DoF of a cell with K single-antenna users and an M -antennas BS equals min(M, K). And for the MIMO interference channel with K antennas at each transmitter and M -antennas at each BS, the DoF per cell is min(M, K, max(M,K) 2 ) by the result of Jafar et al [8]. The comparison among the above two formulas and formula (2) in Theorem 1 is illustrated in Figure 3, where the cases of 2 and 4 antennas at the BS are considered.…”

Section: Discussionmentioning

confidence: 93%

“…Lemma 1 (see [8]). For a multiple access channel with K distributed transmitters (with n k antennas at transmitter k) and a receiver of n R antennas, its degree of freedom is given by…”

Section: Dof For the Two Interfering Multiple-access Channelsmentioning

confidence: 99%

“…For this reason, the past several years have witnessed intensive research activities in the area of the interference channel. Though many insightful and useful results have been found (see for example [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]), many questions still remain open, including the capacity region of the simplest model-the two-user interference channel in the general channel setting.…”

Section: Introductionmentioning

confidence: 99%

“…It is well known that deploying M antennas at the BS is capable of providing M -fold multiplexing gain in the single-cell setting [8]. But when multiple such cells co-exist, a natural question arises: Would the mutual interference among these cells ruin all the multiplexing gain that the multiple-antenna BS could potentially offer?…”

Section: Introductionmentioning

confidence: 99%

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On degrees of freedom of the cellular network

Sun

Liu

Zhu

2010

Sci. China Inf. Sci.

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In this paper, we consider the capacity limits of the cellular network by modeling it as consisting of two mutually interfering multiple access channels with multiple antennas at each receiver (e.g., base station). By developing a tight outerbound as well as an achievable scheme which exploits the idea of interference alignment, we are able to exactly characterize the sum degrees of freedom (DoF) of the network when the channel coefficients are time-or frequency-varying, which equals KM K+min(M,K) (where M and K denote the number of receiver antennas and number of users in per cell, respectively) per cell. From the DoF result, it can be observed that in addition to the multi-user gain which has been reported for the network with single-antenna BSs, there also exists the multi-antenna gain in the cellular network. In particular, when the number of users is large, we can nearly achieve the interference-free DoF of a cellular network with multiple-antenna BSs, which is a somewhat surprising result.

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Section: Discussionmentioning

confidence: 93%

“…Lemma 1 (see [8]). For a multiple access channel with K distributed transmitters (with n k antennas at transmitter k) and a receiver of n R antennas, its degree of freedom is given by…”

Section: Dof For the Two Interfering Multiple-access Channelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On degrees of freedom of the cellular network

Sun

Liu

Zhu

2010

Sci. China Inf. Sci.

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“…그에 대한 대안으로, 다중 이득이 라고도 알려져 있는 DOF (degrees of freedom)에 대 a. Corresponding Author; koyc@korea.ac.kr 한 연구가 진행되어 왔다 [8], [9]. 이것은 정의에 의 해 dlog SNR + o (log (SNR)), 또는,   lim …”

Section: 서 론unclassified

Perfect Interference Alignment for K-user MIMO X Network

Park¹,

Park²,

Kim³

et al. 2011

Journal of the Korean Institute of Electrical and Electronic Ma

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In wireless X networks where all transmitters send the independent messages to all receivers, the theoretical bound on the degrees of freedom (DOF) and interference alignment (IA) scheme for its achievability are given by Cadambe and Jafar [1]. However, IA scheme for wireless X network may be infeasible in practice unless the transmitters have the perfect channel information. In addition, if the transmitter with single antenna uses time-varying channel coefficients as a beamforming vector, the infinite channel extension is required to achieve the theoretical bound on the DOF of wireless X networks with perfect IA scheme. In this paper, we consider K-user MIMO X network where K transmitters and K receivers have M antennas each. While the beamforming vectors have been constructed with multiple channel uses over multiple time slot in the earlier work, we consider the beamforming vectors constructed only by a spatial signature over unit time. Accordingly the channel information at the transmitters can be available instantaneously. Then we propose the perfect IA scheme with no channel extension. Based on our sum-rate analysis and the simulation results, we confirm that our proposed scheme can achieve MK/2 DOF which is quite close to the theoretical bound on the DOF region of wireless X networks.

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2012

Cognitive Radio Communications and Networking

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Degrees of Freedom for the MIMO Interference Channel

Cited by 473 publications

References 14 publications

On degrees of freedom of the cellular network

On degrees of freedom of the cellular network

Perfect Interference Alignment for K-user MIMO X Network

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