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Variable‐power discrete‐rate adaptive modulation with orthogonal space–time block coding for Nakagami‐ m fading channels
Author(s) -
Yu Xiangbin,
Leung ShuHung,
Wong WaiKi
Publication year - 2012
Publication title -
transactions on emerging telecommunications technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.366
H-Index - 47
ISSN - 2161-3915
DOI - 10.1002/ett.1504
Subject(s) - fading , link adaptation , nakagami distribution , mathematics , algorithm , channel state information , lagrange multiplier , code rate , control theory (sociology) , bit error rate , coding (social sciences) , modulation (music) , computer science , topology (electrical circuits) , telecommunications , statistics , mathematical optimization , decoding methods , physics , wireless , control (management) , combinatorics , artificial intelligence , acoustics
The performance system with variable‐power adaptive modulation over Nakagami‐ m fading channels is presented. The optimum switching thresholds for attaining maximum spectrum efficiency (SE) subject to a target bit error rate (BER) and an average power constraint are derived. The existence and uniqueness of the Lagrange multiplier used in the constrained optimization are discussed. The probability density functions of instantaneous signal‐to‐noise ratio for both perfect and imperfect channel state information are derived, which lead to deriving closed‐form SE and BER expressions. Simulation results show that the theoretical analysis and simulation are in good agreement. The variable‐power adaptive modulation with space–time coding provides SE better than the constant power counterpart, and it has performance degradation in SE and BER for imperfect channel state information. Copyright © 2011 John Wiley & Sons, Ltd.