4 research outputs found
Power Allocation in MIMO Wiretap Channel with Statistical CSI and Finite-Alphabet Input
In this paper, we consider the problem of power allocation in MIMO wiretap
channel for secrecy in the presence of multiple eavesdroppers. Perfect
knowledge of the destination channel state information (CSI) and only the
statistical knowledge of the eavesdroppers CSI are assumed. We first consider
the MIMO wiretap channel with Gaussian input. Using Jensen's inequality, we
transform the secrecy rate max-min optimization problem to a single
maximization problem. We use generalized singular value decomposition and
transform the problem to a concave maximization problem which maximizes the sum
secrecy rate of scalar wiretap channels subject to linear constraints on the
transmit covariance matrix. We then consider the MIMO wiretap channel with
finite-alphabet input. We show that the transmit covariance matrix obtained for
the case of Gaussian input, when used in the MIMO wiretap channel with
finite-alphabet input, can lead to zero secrecy rate at high transmit powers.
We then propose a power allocation scheme with an additional power constraint
which alleviates this secrecy rate loss problem, and gives non-zero secrecy
rates at high transmit powers
An Overview of Physical Layer Security with Finite-Alphabet Signaling
Providing secure communications over the physical layer with the objective of
achieving perfect secrecy without requiring a secret key has been receiving
growing attention within the past decade. The vast majority of the existing
studies in the area of physical layer security focus exclusively on the
scenarios where the channel inputs are Gaussian distributed. However, in
practice, the signals employed for transmission are drawn from discrete signal
constellations such as phase shift keying and quadrature amplitude modulation.
Hence, understanding the impact of the finite-alphabet input constraints and
designing secure transmission schemes under this assumption is a mandatory step
towards a practical implementation of physical layer security. With this
motivation, this article reviews recent developments on physical layer security
with finite-alphabet inputs. We explore transmit signal design algorithms for
single-antenna as well as multi-antenna wiretap channels under different
assumptions on the channel state information at the transmitter. Moreover, we
present a review of the recent results on secure transmission with discrete
signaling for various scenarios including multi-carrier transmission systems,
broadcast channels with confidential messages, cognitive multiple access and
relay networks. Throughout the article, we stress the important behavioral
differences of discrete versus Gaussian inputs in the context of the physical
layer security. We also present an overview of practical code construction over
Gaussian and fading wiretap channels, and we discuss some open problems and
directions for future research.Comment: Submitted to IEEE Communications Surveys & Tutorials (1st Revision
An Overview of Physical Layer Security with Finite Alphabet Signaling
Providing secure communications over the physical layer with the objective of achieving secrecy without requiring a secret key has been receiving growing attention within the past decade. The vast majority of the existing studies in the area of physical layer security focus exclusively on the scenarios where the channel inputs are Gaussian distributed. However, in practice, the signals employed for transmission are drawn from discrete signal constellations such as phase shift keying and quadrature amplitude modulation. Hence, understanding the impact of the finite-alphabet input constraints and designing secure transmission schemes under this assumption is a mandatory step towards a practical implementation of physical layer security. With this motivation, this article reviews recent developments on physical layer security with finite-alphabet inputs. We explore transmit signal design algorithms for single-antenna as well as multi-antenna wiretap channels under different assumptions on the channel state information at the transmitter. Moreover, we present a review of the recent results on secure transmission with discrete signaling for various scenarios including multi-carrier transmission systems, broadcast channels with confidential messages, cognitive multiple access and relay networks. Throughout the article, we stress the important behavioral differences of discrete versus Gaussian inputs in the context of the physical layer security. We also present an overview of practical code construction over Gaussian and fading wiretap channels, and discuss some open problems and directions for future research