Covert transmission is investigated for a cooperative deception strategy,
where a cooperative jammer (Jammer) tries to attract a multi-antenna adversary
(Willie) and degrade the adversary's reception ability for the signal from a
transmitter (Alice). For this strategy, we formulate an optimization problem to
maximize the covert rate when three different types of channel state
information (CSI) are available. The total power is optimally allocated between
Alice and Jammer subject to Kullback-Leibler (KL) divergence constraint.
Different from the existing literature, in our proposed strategy, we also
determine the optimal transmission power at the jammer when Alice is silent,
while existing works always assume that the jammer's power is fixed.
Specifically, we apply the S-procedure to convert infinite constraints into
linear-matrix-inequalities (LMI) constraints. When statistical CSI at Willie is
available, we convert double integration to single integration using asymptotic
approximation and substitution method. In addition, the transmission strategy
without jammer deception is studied as a benchmark. Finally, our simulation
results show that for the proposed strategy, the covert rate is increased with
the number of antennas at Willie. Moreover, compared to the benchmark, our
proposed strategy is more robust in face of imperfect CSI.Comment: 33 pages, 8 Figure