Multi-User Diversity vs. Accurate Channel State Information in MIMO Downlink Channels

Abstract

In a multiple transmit antenna, single antenna per receiver downlink channel with limited channel state feedback, we consider the following question: given a constraint on the total system-wide feedback load, is it preferable to get low-rate/coarse channel feedback from a large number of receivers or high-rate/high-quality feedback from a smaller number of receivers? Acquiring feedback from many receivers allows multi-user diversity to be exploited, while high-rate feedback allows for very precise selection of beamforming directions. We show that there is a strong preference for obtaining high-quality feedback, and that obtaining near-perfect channel information from as many receivers as possible provides a significantly larger sum rate than collecting a few feedback bits from a large number of users.

Submitted to IEEE Transactions on Communications, July 2009

References in corpus (5)

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• Space Division Multiple Access with a Sum Feedback Rate Constraint
• On the Capacity of Fading MIMO Broadcast Channels with Imperfect Transmitter Side-Information
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Cited by in corpus (7)

• An Overview on Resource Allocation Techniques for Multi-User MIMO Systems
• Antenna Grouping based Feedback Compression for FDD-based Massive MIMO Systems
• Multi-mode Transmission for the MIMO Broadcast Channel with Imperfect Channel State Information
• Optimal Feedback Rate Sharing Strategy in Zero-Forcing MIMO Broadcast Channels
• Uplink Downlink Rate Balancing in Cooperating Cellular Networks
• Limited Feedback Designs for Machine-type Communications Exploiting User Cooperation
• Delay Performance of the Multiuser MISO Downlink under Imperfect CSI and Finite Length Coding