On the power amplifier nonlinearity in MIMO transmit beamforming systems

Abstract
In this paper, single-carrier multiple-input multiple-output (MIMO) transmit beamforming (TB) systems in the presence of high-power amplifier (HPA) nonlinearity are investigated. Specifically, due to the suboptimality of the conventional maximal ratio transmission/maximal ratio combining (MRT/MRC) under HPA nonlinearity, we propose the optimal TB scheme with the optimal beamforming weight vector and combining vector, for MIMO systems with nonlinear HPAs. Moreover, an alternative suboptimal but much simpler TB scheme, namely, quantized equal gain transmission (QEGT), is proposed. The latter profits from the property that the elements of the beamforming weight vector have the same constant modulus. The performance of the proposed optimal TB scheme and QEGT/MRC technique in the presence of the HPA nonlinearity is evaluated in terms of the average symbol error probability and mutual information with the Gaussian input, considering the transmission over uncorrelated quasi-static frequency-flat Rayleigh fading channels. Numerical results are provided and show the effects on the performance of several system parameters, namely, the HPA parameters, numbers of antennas, quadrature amplitude modulation modulation order, number of pilot symbols, and cardinality of the beamforming weight vector codebook for QEGT. © 2012 IEEE.

Citation
Qi, J., & Aissa, S. (2012). On the Power Amplifier Nonlinearity in MIMO Transmit Beamforming Systems. IEEE Transactions on Communications, 60(3), 876–887. doi:10.1109/tcomm.2012.021712.110006

Acknowledgements
This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada and the Quebec Government Fonds Quebecois de la Recherche sur la Nature et les Technologies (FQRNT). Part of this work was presented at IEEE PIMRC'09 and IEEE PIMRC'10.

Publisher
Institute of Electrical and Electronics Engineers (IEEE)

Journal
IEEE Transactions on Communications

DOI
10.1109/TCOMM.2012.021712.110006

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