Low-SNR Asymptotic Capacity of MIMO Optical Intensity Channels with Peak and Average Constraints

Anas Chaaban, Zouheir Rezki, Mohamed-Slim Alouini

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The low-SNR asymptotic capacity of the multipleinput multiple-output (MIMO) optical intensity channel is studied under both average and peak intensity constraints. We focus on low SNR, which can be modeled as the scenario where both constraints proportionally vanish, or where the peak constraint is held constant while the average constraint vanishes. A capacity upper bound is derived, and is shown to be tight at low SNR under both scenarios. The capacity achieving input distribution at low SNR is shown to be a maximally-correlated vectorbinary input distribution. Consequently, the low-SNR capacity of the channel is characterized. As a byproduct, it is shown that for a channel with peak intensity constraints only, or with peak intensity constraints and individual (per aperture) average intensity constraints, a simple scheme composed of coded onoff keying, spatial repetition, and maximum-ratio combining is optimal at low SNR.
Original languageEnglish (US)
Pages (from-to)1-1
Number of pages1
JournalIEEE Transactions on Communications
Issue number10
StatePublished - May 29 2018

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: His work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC). His work is supported in part by the Qatar National Research Fund (a member of Qatar Foundation) under Grant NPRP 9-077-2-036. The statements made herein are solely the responsibility of the authors.


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