On the Beamforming Optimality Range in TIMO Channels with Common and Individual Input Power Constraints

Author

Al-Ahmadi, Saad ; Yanikomeroglu, Halim

Author_Institution

Dept. of Electr. Eng., King Fahd Univ. of Pet. & Miner., Dhahran, Saudi Arabia

Volume

59

Issue

3

fYear

2011

fDate

3/1/2011 12:00:00 AM

Firstpage

648

Lastpage

651

Abstract

In this letter, the effect of the input power constraint on the beamforming optimality range in Gaussian two-input multiple-output (TIMO) channels is investigated. The obtained expressions, using standard Lagrangian formulation, determine explicitly the range of the input signal-to-noise ratio (SNR) for which beamforming (rank-1 signaling) is optimal for TIMO channels for both the common power constraint and the individual power constraint cases. Moreover, the obtained results are extended to random TIMO channels, with channel state information at the receiver only, using the Jensen´s upper bound on the mutual information.

Keywords

MIMO communication; array signal processing; covariance matrices; Gaussian two-input multiple-output channels; Jensen´s upper bound; TIMO channels; beamforming optimality range; input power constraints; mutual information; signal-to-noise ratio; standard Lagrangian formulation; MIMO channels; beamforming; common power constraint; individual power constraints; input covariance matrix; mutual information;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/TCOMM.2011.010411.090022

Filename

5682544