Optimum Mode-Switching-Assisted Constant-Power Single- and Multicarrier Adaptive Modulation
Choi, B.J. and Hanzo, L. (2003) Optimum Mode-Switching-Assisted Constant-Power Single- and Multicarrier Adaptive Modulation. IEEE Transactions on Vehicular Technology, 52, (3), 536-560.
A set of optimum mode-switching levels is derived for a generic constant-power adaptive-modulation scheme based on a closed-form expression of the average bit error ratio (BER) and the average bits-per-symbol (BPS) throughput of the adaptive-modulation scheme. This results in a constant BER, variable-throughput arrangement. The corresponding BPS throughput performance and the achievable signal-to-noise ratio (SNR) gain are investigated for the optimum mode-switching assisted constant-power adaptive-modulation schemes employing various diversity schemes, including maximal ratio combining (MRC) receive-antenna diversity, a two-dimensional RAKE receiver, as well as transmit-diversity aided space-time (ST) coding, when communicating over various fading scenarios. The BPS throughput of our constant-power adaptive quadrature amplitude modulation (AQAM) scheme approaches the throughput of variable-power variable-rate AQAM within 1 dB. However, the achievable throughput gain of the adaptive-modulation scheme, in comparison to conventional fixed-mode modems, is substantially reduced as the diversity order of the receiver is increased. Hence, adaptive modulation constitutes a lower complexity alternative to multiple-transmitter and receiver-based systems when considering the range of techniques that can be used for mitigating the effects of the channel-quality fluctuations imposed by wireless channels. Index Terms—Adaptive modulation, adaptive quadrature amplitude modulation (AQAM), fading counter measures, Lagrangian optimization for adaptive modulation, optimum switching levels for adaptive modulation.
|Divisions:||Faculty of Physical Sciences and Engineering > Electronics and Computer Science > Comms, Signal Processing & Control
|Date Deposited:||01 Dec 2003|
|Last Modified:||07 Mar 2012 16:12|
|Contributors:||Choi, B.J. (Author)
Hanzo, L. (Author)
|Further Information:||Google Scholar|
|ISI Citation Count:||56|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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