The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Limited Feedback MIMO Techniques for Temporally Correlated Channels and Linear Receivers

Eduardo Zacarías Brach

Doctoral dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the School of Electrical Engineering for public examination and debate in Auditorium S1 at the Aalto University School of Electrical Engineering (Espoo, Finland) on the 3rd of February 2012 at 12 noon.

Overview in PDF format (ISBN 978-952-60-4478-1)   [1172 KB]
Dissertation is also available in print (ISBN 978-952-60-4477-4)

Abstract

Advanced mobile wireless networks will make extensive use of multiantenna (MIMO) transceivers to comply with high requirements of data rates and reliability. The use of feedback channels is of paramount importance to achieve this goal in systems employing frequency division duplexing (FDD). The design of the feedback mechanism is challenging due to the severe constraints imposed by computational complexity and feedback bandwidth restrictions.

This thesis addresses the design of transmission strategies in both single-user and multi-user MIMO systems, based on compact feedback messages. First, recursive feedback mechanisms for single-user transmission scenarios are proposed, including stochastic gradient techniques, deterministic updates based on Givens rotations and low computational complexity schemes based on partial update filtering concepts. Thereafter, channel feedback algorithms are proposed, and a convergence analysis for static channels is presented. These algorithms can be used to provide channel side information to any multi-user MIMO solution. A limited-feedback decentralized multi-user MIMO solution is proposed, which avoids the need for explicit channel feedback. A feed-forward technique is proposed, which allows our methods to operate in presence of feedback errors.

The performance of all the proposed algorithms is illustrated via link-level simulations, where the effect of different parameter values is assessed. Our results show that the proposed methods outperform existing limited-feedback counterparts over a range of low to medium mobile speeds, for moderate antenna array sizes that are deemed practical for commercial deployment. The computational complexity reduction of some of the proposed algorithms is also shown to be considerable, when compared to existing techniques.

This thesis consists of an overview and of the following 9 publications:

  1. E. Zacarías B., R. Wichman and S. Werner. Filtered gradient algorithm for closed loop MIMO systems. Proc. IEEE VTC-Spring, Stockholm, May 2005.
  2. E. Zacarías B., S. Werner and R. Wichman. Adaptive transmit eigenbeamforming with stochastic unitary plane rotations in MIMO systems with linear receivers. Proc. IEEE IZS 2006, Zurich, February 2006.
  3. E. Zacarías B., S. Werner and R. Wichman. Partial update adaptive transmit beamforming with limited feedback. Proc. IEEE ICASSP 2006, Tolousse, May 2006.
  4. E. Zacarías B., S. Werner and R. Wichman. Enhanced partial update beamforming for closed loop MIMO systems. Proc. IEEE PIMRC, Helsinki, September 2006.
  5. E. Zacarías B., S. Werner and R. Wichman. Distributed Jacobi eigen-beamforming for closed-loop MIMO systems. IEEE Commun. Lett., vol. 10, no. 12, December 2006.
  6. E. Zacarías B., S. Werner and R. Wichman. Link adaptation with distributed Jacobi eigenbeamforming for MIMO systems. Proc. IEEE ISWCS 2007, Trondheim, October 2007.
  7. E. Zacarías B., S. Werner, R. Wichman and T. Riihonen. Single-bit closed-loop quasi-orthogonal space-time codes for MIMO systems. Proc. IEEE SPAWC, Perugia, June 2009.
  8. E. Zacarías B., S. Werner and R. Wichman. Limited feedback multiuser MIMO techniques for time-correlated channels. EURASIP Journal on Advances in Signal Processing, doi:10.1155/2009/104950, October 2009.
  9. E. Zacarías B., S. Werner and R. Wichman. Decentralized limited-feedback multiuser MIMO for temporally correlated channels. Journal of Electrical and Computer Engineering, doi:10.1155/2010/915653, July 2010.

Errata of publications 2, 3 and 8

Keywords: multiantenna systems, multiple-input multiple-output, limited feedback, wireless communications

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© 2012 Aalto University

Last update 2012-10-31