Power Control for Space-Time Block Coded MIMO System with Beamforming and Imperfect Channel State Information

Xiang-bin YU  Quan KUANG  Qing-min MENG  Shu-hung LEUNG  

IEICE TRANSACTIONS on Communications   Vol.E94-B    No.5    pp.1416-1423
Publication Date: 2011/05/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.1416
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
power control,  space-time block coding,  beamforming,  imperfect channel state information,  MIMO,  

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In this paper, an optimal power control for minimizing bit error rate (BER) subject to a power constraint for space-time block coded MIMO systems with beamforming over Rayleigh fading channels under imperfect channel state information (CSI) is presented. The optimal power control procedure is developed. It is shown that the Lagrange multiplier for the constrained optimization does exist and is unique. To simplify the power control procedure, a closed-form suboptimal power control scheme is drived based on the asymptotic performance analysis of the optimal power control and Taylor's series expansion. The calculation of the suboptimal power control is straightforward with low computational complexity. Moreover, the suboptimal scheme can provide the BER performance close to that of the optimal power control and is lower than that of the existing suboptimal scheme. Simulation results show that the proposed two power control schemes can provide BER lower than that of the equal power allocation and the existing suboptimal scheme under imperfect CSI.