The Degrees of Freedom Regions of Two-User and Certain Three-User MIMO Broadcast Channels with Delayed CSIT

Abstract

The degrees of freedom (DoF) region of the fast-fading MIMO (multiple-input multiple-output) Gaussian broadcast channel (BC) is studied when there is delayed channel state information at the transmitter (CSIT). In this setting, the channel matrices are assumed to vary independently across time and the transmitter is assumed to know the channel matrices with some arbitrary finite delay. An outer-bound to the DoF region of the general $K$-user MIMO BC (with an arbitrary number of antennas at each terminal) is derived. This outer-bound is then shown to be tight for two classes of MIMO BCs, namely, (a) the two-user MIMO BC with arbitrary number of antennas at all terminals, and (b) for certain three-user MIMO BCs where all three receivers have an equal number of antennas and the transmitter has no more than twice the number of antennas present at each receivers. The achievability results are obtained by developing an interference alignment scheme that optimally accounts for multiple, and possibly distinct, number of antennas at the receivers.

27 pages, 6 figures; submitted to IEEE Trans. on Information Theory, Dec. 2011

References in corpus (5)

• On Degrees of Freedom Region of MIMO Networks without CSIT
• Interference Alignment for the MIMO Interference Channel with Delayed Local CSIT
• The Degrees of Freedom Regions of MIMO Broadcast, Interference, and Cognitive Radio Channels with No CSIT
• Retrospective Interference Alignment
• Aiming Perfectly in the Dark - Blind Interference Alignment through Staggered Antenna Switching

Cited by in corpus (9)

• Degrees-of-Freedom Region of the MISO Broadcast Channel with General Mixed-CSIT
• On the Synergistic Benefits of Alternating CSIT for the MISO BC
• On X-Channels with Feedback and Delayed CSI
• Minimum CSIT to achieve Maximum Degrees of Freedom for the MISO BC
• On Cooperative Multiple Access Channels with Delayed CSI at Transmitters
• Symmetric Two-User MIMO BC and IC with Evolving Feedback
• Achievable DoF Regions of Three-User MIMO Broadcast Channel with Delayed CSIT
• Retroactive Anti-Jamming for MISO Broadcast Channels
• Coherence Disparity in Broadcast and Multiple Access Channels