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  • Research Article
  • Open Access

Eigenstructures of MIMO Fading Channel Correlation Matrices and Optimum Linear Precoding Designs for Maximum Ergodic Capacity

EURASIP Journal on Advances in Signal Processing20072007:029749

  • Received: 27 October 2006
  • Accepted: 25 March 2007
  • Published:


The ergodic capacity of MIMO frequency-flat and -selective channels depends greatly on the eigenvalue distribution of spatial correlation matrices. Knowing the eigenstructure of correlation matrices at the transmitter is very important to enhance the capacity of the system. This fact becomes of great importance in MIMO wireless systems where because of the fast changing nature of the underlying channel, full channel knowledge is difficult to obtain at the transmitter. In this paper, we first investigate the effect of eigenvalues distribution of spatial correlation matrices on the capacity of frequency-flat and -selective channels. Next, we introduce a practical scheme known as linear precoding that can enhance the ergodic capacity of the channel by changing the eigenstructure of the channel by applying a linear transformation. We derive the structures of precoders using eigenvalue decomposition and linear algebra techniques in both cases and show their similarities from an algebraic point of view. Simulations show the ability of this technique to change the eigenstructure of the channel, and hence enhance the ergodic capacity considerably.


  • Correlation Matrice
  • Eigenvalue Distribution
  • Selective Channel
  • Ergodic Capacity
  • Channel Correlation

Authors’ Affiliations

Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montréal, QC, H3A 2A7, Canada


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© H. R. Bahrami and T. Le-Ngoc 2007

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.