Adaptive Modulation for MIMO Beamforming under Average BER Constraints and Imperfect CSI

Abstract

Adaptive modulation schemes for fading channels are usually required to fulfill certain long-term average BER targets. However, for simplicity and mathematical tractability, these schemes are often designed by fixing the short-term instantaneous BER to the target value. In this paper, the analysis and design of variable-rate variable-power QAM schemes with average BER constraints are tackled for a MIMO beamforming system with MRC and imperfect CSI. The SISO system is considered as a special case of these more general results. Approximate closed-form policies are derived for continuous rate and power adaptation which are compared to fully discrete policies designed numerically. Closed-form expressions for the ASE of the proposed policies are derived and evaluated. Our results indicate that imperfect CSI and discrete rate and power constraints do not significantly degrade performance.

DOI: 10.1109/ICC.2006.254930

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Cite this paper

@inproceedings{Paris2006AdaptiveMF, title={Adaptive Modulation for MIMO Beamforming under Average BER Constraints and Imperfect CSI}, author={Jos{\'e} F. Paris and Andrea J. Goldsmith}, booktitle={ICC}, year={2006} }