Open Access

Stable Transmission in the Time-Varying MIMO Broadcast Channel

  • Adam L. Anderson1Email author,
  • James R. Zeidler1 and
  • Michael A. Jensen2
EURASIP Journal on Advances in Signal Processing20082008:617020

https://doi.org/10.1155/2008/617020

Received: 1 June 2007

Accepted: 19 December 2007

Published: 17 January 2008

Abstract

Both linear and nonlinear transmit precoding strategies based on accurate channel state information (CSI) can significantly increase available throughput in a multiuser wireless system. With propagation delay, infrequent channel updates, lag due to network layer overhead, and time-varying node position or environment characteristics, channel knowledge becomes outdated and CSI-based transmission schemes can experience severe performance degradation. This paper studies the performance of precoding techniques for the multiuser broadcast channel with outdated CSI at the transmitter. Traditional channel models as well as channel realizations measured by a wideband channel sounder are used in the analysis. With measured data from an outdoor urban environment, it is further shown the existence of stable subspaces upon which transmission is possible without any instantaneous CSI at the transmitter. Such transmissions allow for consistent performance curves at the cost of initial suboptimality compared to CSI-based schemes.

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Authors’ Affiliations

(1)
Department of Electrical and Computer Engineering, University of California
(2)
Department of Electrical and Computer Engineering, Brigham Young University

Copyright

© Adam L. Anderson et al. 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.