Abstract
We consider secret-key agreement with public discussion over a multiple-input single output (MISO) Gaussian channel with an amplitude constraint. We prove that the capacity is achieved by a discrete input, i.e., an input whose support is sparse. The proof follows from the concavity of the conditional mutual information in terms of the input distribution and hence the Karush-Kuhn-Tucker (KKT) condition provides a necessary and sufficient condition for optimality. Then, a contradiction argument that rules out the non-sparsity of any optimal input's support is utilized. The latter approach is essential to apply the identity theorem in a multidimensional setting as Rn is not an open subset of Cn.
Original language | English (US) |
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Title of host publication | 2017 IEEE International Symposium on Information Theory, ISIT 2017 |
Publisher | Institute of Electrical and Electronics Engineers Inc. |
Pages | 1534-1538 |
Number of pages | 5 |
ISBN (Electronic) | 9781509040964 |
DOIs | |
State | Published - Aug 9 2017 |
Event | 2017 IEEE International Symposium on Information Theory, ISIT 2017 - Aachen, Germany Duration: Jun 25 2017 → Jun 30 2017 |
Publication series
Name | IEEE International Symposium on Information Theory - Proceedings |
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ISSN (Print) | 2157-8095 |
Conference
Conference | 2017 IEEE International Symposium on Information Theory, ISIT 2017 |
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Country/Territory | Germany |
City | Aachen |
Period | 06/25/17 → 06/30/17 |
Bibliographical note
Publisher Copyright:© 2017 IEEE.
Keywords
- Discrete input
- Information-theoretic security
- Karush-Kuhn-Tucker (KKT) conditions
- Secret-key agreement
ASJC Scopus subject areas
- Theoretical Computer Science
- Information Systems
- Applied Mathematics
- Modeling and Simulation