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.
| Original language | English |
|---|---|
| Article number | 5682544 |
| Pages (from-to) | 648-651 |
| Number of pages | 4 |
| Journal | IEEE Transactions on Communications |
| Volume | 59 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2011 |
Bibliographical note
Funding Information:Paper approved by D. L. Goeckel, the Editor for Space-Time and OFDM of the IEEE Communications Society. Manuscript received February 19, 2009; revised December 15, 2009 and March 24, 2010. S. Al-Ahmadi’s work was supported by King Fahd University of Petroleum and Minerals, Saudi Arabia. S. Al-Ahmadi is currently with the Department of Electrical Engineering, King Fahd University of Petroleum and Minerals, Saudi Arabia (e-mail: [email protected]). H. Yanikomeroglu is with the Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada (e-mail: [email protected]). Digital Object Identifier 10.1109/TCOMM.2011.010411.090022
Keywords
- MIMO channels
- beamforming
- common power constraint
- individual power constraints
- input covariance matrix
- mutual information
ASJC Scopus subject areas
- Electrical and Electronic Engineering