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  • Research Article
  • Open Access

A Design Framework for Scalar Feedback in MIMO Broadcast Channels

EURASIP Journal on Advances in Signal Processing20072008:574784

  • Received: 15 June 2007
  • Accepted: 13 November 2007
  • Published:


Joint linear beamforming and scheduling are performed in a system where limited feedback is present at the transmitter side. The feedback conveyed by each user to the base station consists of channel direction information (CDI) based on a predetermined codebook and a scalar metric with channel quality information (CQI) used to perform user scheduling. In this paper, we present a design framework for scalar feedback in MIMO broadcast channels with limited feedback. An approximation on the sum rate is provided for the proposed family of metrics, which is validated through simulations. For a given number of active users and average SNR conditions, the base station is able to update certain transmission parameters in order to maximize the sum-rate function. On the other hand, the proposed sum-rate function provides a means of simple comparison between transmission schemes and scalar feedback techniques. Particularly, the sum rate of SDMA and time division multiple access (TDMA) is compared in the following extreme regimes: large number of users, high SNR, and low SNR. Simulations are provided to illustrate the performance of various scalar feedback techniques based on the proposed design framework.


  • Transmission Scheme
  • Time Division Multiple Access
  • Design Framework
  • Publisher Note
  • SDMA

Publisher note

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Authors’ Affiliations

Eurecom Institute, BP 193, Sophia-Antipolis Cedex, 06904, France


© R. de Francisco and D. T. M. Slock. 2008

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.