6 research outputs found
Jamming Games in the MIMO Wiretap Channel With an Active Eavesdropper
This paper investigates reliable and covert transmission strategies in a
multiple-input multiple-output (MIMO) wiretap channel with a transmitter,
receiver and an adversarial wiretapper, each equipped with multiple antennas.
In a departure from existing work, the wiretapper possesses a novel capability
to act either as a passive eavesdropper or as an active jammer, under a
half-duplex constraint. The transmitter therefore faces a choice between
allocating all of its power for data, or broadcasting artificial interference
along with the information signal in an attempt to jam the eavesdropper
(assuming its instantaneous channel state is unknown). To examine the resulting
trade-offs for the legitimate transmitter and the adversary, we model their
interactions as a two-person zero-sum game with the ergodic MIMO secrecy rate
as the payoff function. We first examine conditions for the existence of
pure-strategy Nash equilibria (NE) and the structure of mixed-strategy NE for
the strategic form of the game.We then derive equilibrium strategies for the
extensive form of the game where players move sequentially under scenarios of
perfect and imperfect information. Finally, numerical simulations are presented
to examine the equilibrium outcomes of the various scenarios considered.Comment: 27 pages, 8 figures. To appear, IEEE Transactions on Signal
Processin
A Secure Communication Game with a Relay Helping the Eavesdropper
In this work a four terminal complex Gaussian network composed of a source, a
destination, an eavesdropper and a jammer relay is studied under two different
set of assumptions: (i) The jammer relay does not hear the source transmission,
and (ii) The jammer relay is causally given the source message. In both cases
the jammer relay assists the eavesdropper and aims to decrease the achievable
secrecy rates. The source, on the other hand, aims to increase it. To help the
eavesdropper, the jammer relay can use pure relaying and/or send interference.
Each of the problems is formulated as a two-player, non-cooperative, zero-sum
continuous game. Assuming Gaussian strategies at the source and the jammer
relay in the first problem, the Nash equilibrium is found and shown to be
achieved with mixed strategies in general. The optimal cumulative distribution
functions (cdf) for the source and the jammer relay that achieve the value of
the game, which is the Nash equilibrium secrecy rate, are found. For the second
problem, the Nash equilibrium solution is found and the results are compared to
the case when the jammer relay is not informed about the source message.Comment: 13 pages, 11 figures, to appear in IEEE Transactions on Information
Forensics and Security, Special Issue on Using the Physical Layer for
Securing the Next Generation of Communication Systems. This is the journal
version of cs.IT:0911.008