### Abstract

While Gaussian signalling is assumed in many studies on covert
communications, its optimality has not been carefully investigated. In
this work, we examine this optimality by considering the approach of
upper bounding D(p
_{0}
(y)∥p
_{1}
(y)) as the covert communication constraint, where D(p
_{0}
(y)∥p
_{1}
(y)) is the Kullback-Leibler divergence from p
_{0}
(y) to p
_{1}
(y), p
_{0}
(y) and p
_{1}
(y) are the likelihood functions of the observation y at the warden
under the null hypothesis (no covert transmission) and alternative
hypothesis (a covert transmission occurs), respectively. Considering
additive white Gaussian noise at both the receiver and the warden, we
prove that Gaussian signalling is not optimal in terms of maximizing the
mutual information of transmitted and received signals for covert
communications with D(p
_{0}
(y)∥p
_{1}
(y)) ≤ 2ϵ
^{2}
as the constraint. We also explicitly show a skew-normal signalling can
outperform Gaussian signalling in terms of achieving higher mutual
information subject to the same covertness constraint D(p
_{0}
(y)∥p
_{1}
(y)) ≤ 2ϵ
^{2}
.

Original language | English |
---|---|

Title of host publication | 2019 IEEE International Conference on Communications (ICC) |

Subtitle of host publication | proceedings |

Place of Publication | Piscataway, NJ |

Publisher | Institute of Electrical and Electronics Engineers (IEEE) |

Pages | 1-6 |

Number of pages | 6 |

ISBN (Electronic) | 9781538680889 |

ISBN (Print) | 9781538680896 |

DOIs | |

Publication status | Published - 2019 |

Event | 2019 IEEE International Conference on Communications, ICC 2019 - Shanghai, China Duration: 20 May 2019 → 24 May 2019 |

### Publication series

Name | |
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ISSN (Print) | 1550-3607 |

ISSN (Electronic) | 1938-1883 |

### Conference

Conference | 2019 IEEE International Conference on Communications, ICC 2019 |
---|---|

Country | China |

City | Shanghai |

Period | 20/05/19 → 24/05/19 |

### Fingerprint

### Cite this

*2019 IEEE International Conference on Communications (ICC): proceedings*(pp. 1-6). Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE). https://doi.org/10.1109/ICC.2019.8761750