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Design and performance assessment of high-capacity MIMO architectures in the presence of a line-of-sight component

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)2194 - 2202
Number of pages9
JournalIEEE Transactions on Vehicular Technology
Journal issue4, part 2
StatePublished - Sep 2007


In this paper, the capacity of multiple-input multiple- output (MIMO) communication systems is investigated in the presence of a line-of-sight (LoS) component. Under this scenario, the channel-response matrix is usually rank deficient due to the high correlation between the LoS responses. Previous studies have shown that this problem can be overcome by the use of specifically designed antenna arrays. The antenna elements are positioned to preserve orthogonality and, hence, maximize the LoS-channel rank. To help in the design of such architectures, we derive a 3-D criterion for maximizing the LoS MIMO capacity as a function of the distance, the orientation, and the spacing of the arrays. The sensitivity of these systems to imperfect positioning and orientation is examined using a geometric MIMO model. The spectral efficiency is also investigated in the presence of scattered signals in the environment using a stochastic channel model and a Monte Carlo simulator. To demonstrate the validity of our predictions, we present the results of two MIMO measurement campaigns in an anechoic and an indoor environment where the measured capacities are compared with the capacities obtained from our models. All experimental results validate our predictions and, hence, confirm the potential for superior MIMO performance (when the developed criterion is applied) in strong LoS channels.

Additional information

Publisher: Institute of Electrical and Electronics Engineers (IEEE) Rose publication type: Journal article Sponsorship: The authors would like to thank Mitsubishi Electric Information Technology Centre Europe—Visual Information Laboratory for sponsoring this work. Terms of use: Copyright © 2007 IEEE. Reprinted from IEEE Transactions on Vehicular Technology. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Bristol's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to By choosing to view this document, you agree to all provisions of the copyright laws protecting it.

    Research areas

  • antenna arrays, channel capacity, K-factor, line-of-sight (LoS), multiple-input multiple-output (MIMO), Ricean channel

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