Computing the Degrees of Freedom for Arbitrary MIMO Interference Channels

TitleComputing the Degrees of Freedom for Arbitrary MIMO Interference Channels
Publication TypeConference Paper
Year of Publication2013
AuthorsÓ. González, C. Lameiro, J. Vía, C. Beltrán, and I. Santamaría
Conference NameIEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2013)
Month PublishedMay
Conference LocationVancouver, Canada
ISBN Number978-1-4799-0356-6
Keywordsconvex optimization, degrees of freedom, interference alignment, multiple-input multiple-output
AbstractIn this paper we provide an efficient procedure to compute the total number of degrees of freedom (DoF), achievable by linear beamforming, of the K-user multiple-input multiple-output (MIMO) interference channel with an arbitrary number of Tx-Rx antennas at each link. Firstly, we derive an analytical outer bound that generalizes the results that exist for the symmetric K-user M x N interference channel. Secondly, we obtain a tighter bound by solving a convex optimization problem that includes as constraints the DoF characterizations for point-to-point MIMO links and for 2-user interference channels. The solution to this convex problem admits an interesting waterfilling interpretation. Finally, exploiting this outer bound and using a recently proposed feasibility test, we show that it is possible to obtain the DoF for any interference channel in an efficient way. Some simulations results are included to illustrate the tightness of the derived bounds, as well as to study the DoF achievable for the 4-user channel when we distribute the total number of antennas among users and between transmitters and receivers in different ways.
Refereed DesignationRefereed
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