TY - GEN
T1 - Is Gaussian signalling optimal for covert communications?
AU - Yan, Shihao
AU - Cong, Yirui
AU - Hanly, Stephen V.
AU - Zhou, Xiangyun
PY - 2019
Y1 - 2019
N2 - 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
.
AB - 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
.
UR - http://www.scopus.com/inward/record.url?scp=85070233361&partnerID=8YFLogxK
U2 - 10.1109/ICC.2019.8761750
DO - 10.1109/ICC.2019.8761750
M3 - Conference proceeding contribution
AN - SCOPUS:85070233361
SN - 9781538680896
SP - 1
EP - 6
BT - 2019 IEEE International Conference on Communications (ICC)
PB - Institute of Electrical and Electronics Engineers (IEEE)
CY - Piscataway, NJ
T2 - 2019 IEEE International Conference on Communications, ICC 2019
Y2 - 20 May 2019 through 24 May 2019
ER -