Orthogonal designs optimize achievable dispersion for coherent MISO channels
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Polyansky_Orthogonal designs.pdf
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284.2 KB
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Author(s)
Polyanskiy, Yury
Collins, Austin Daniel
Date Issued
June 2014
Journal
Proceedings of the 2014 IEEE International Symposium on Information Theory
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Citation
Collins, Austin, and Yury Polyanskiy. “Orthogonal Designs Optimize Achievable Dispersion for Coherent MISO Channels.” 2014 IEEE International Symposium on Information Theory (June 2014).
Version
Author's final manuscript
Abstract
This work addresses the question of finite block-length fundamental limits of coherently demodulated multi-antenna channels, subject to frequency non-selective isotropic fading. Specifically we present achievability bound for the channel dispersion - a quantity known to determine the delay required to achieve capacity. It is shown that a commonly used isotropic Gaussian input, which is only one of many possible capacity achieving distributions, is suboptimal. Optimal inputs minimizing channel dispersion turn out to include a family of modulation techniques known as orthogonal designs (in particular, Alamouti's scheme). For 8 transmit antennas numerical evaluation shows that up to 40% of additional penalty in delay is incurred by using isotropic codewords (compared to dispersion-optimal architecture exploiting transmit diversity).
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1109/ISIT.2014.6875289
