18 research outputs found
A Survey of Physical Layer Security Techniques for 5G Wireless Networks and Challenges Ahead
Physical layer security which safeguards data confidentiality based on the
information-theoretic approaches has received significant research interest
recently. The key idea behind physical layer security is to utilize the
intrinsic randomness of the transmission channel to guarantee the security in
physical layer. The evolution towards 5G wireless communications poses new
challenges for physical layer security research. This paper provides a latest
survey of the physical layer security research on various promising 5G
technologies, including physical layer security coding, massive multiple-input
multiple-output, millimeter wave communications, heterogeneous networks,
non-orthogonal multiple access, full duplex technology, etc. Technical
challenges which remain unresolved at the time of writing are summarized and
the future trends of physical layer security in 5G and beyond are discussed.Comment: To appear in IEEE Journal on Selected Areas in Communication
Regularized Channel Inversion for Simultaneous Confidential Broadcasting and Power Transfer: A Large System Analysis
We propose for the first time new transmission
schemes based on linear precoding to enable simultaneous confidential
broadcasting and power transfer (SCBPT) in a multiuser
multi-input single-output (MISO) network, where a BS with N
antennas simultaneously transmits power and confidential messages
to K single-antenna users. We first design two transmission
schemes based on the rules of regularized channel inversion
(RCI) for both power splitting (PS) and time switching (TS)
receiver architectures, namely, RCI-PS and RCI-TS schemes.
For each scheme, we derive channel-independent expressions to
approximate the secrecy sum rate and the harvested power in
the large-system regime where K, N → ∞ with a fixed ratio
β = K/N. Based on the large-system results, we jointly optimize
the regularization parameter of the RCI and the PS ratio or the
TS ratio such that the secrecy sum rate is maximized subject
to an energy-harvesting constraint. We then present the tradeoff
between the secrecy sum rate and the harvested power achieved
by each scheme, and find that neither scheme always outperforms
the other one. Motivated by this fact, we design an RCI-hybrid
scheme based on the RCI and a newly proposed hybrid receiver
architecture. The hybrid receiver architecture takes advantages
of both the PS and TS receiver architectures. We show that the
RCI-hybrid scheme outperforms both the RCI-PS and RCI-TS
schemes.ARC Discovery Projects Grant DP15010390
Secure Transmission in Multi-Cell Massive MIMO Systems
In this paper, we consider physical layer security provisioning in multi-cell
massive multiple-input multiple-output (MIMO) systems. Specifically, we
consider secure downlink transmission in a multi-cell massive MIMO system with
matched-filter precoding and artificial noise (AN) generation at the base
station (BS) in the presence of a passive multi-antenna eavesdropper. We
investigate the resulting achievable ergodic secrecy rate and the secrecy
outage probability for the cases of perfect training and pilot contamination.
Thereby, we consider two different AN shaping matrices, namely, the
conventional AN shaping matrix, where the AN is transmitted in the null space
of the matrix formed by all user channels, and a random AN shaping matrix,
which avoids the complexity associated with finding the null space of a large
matrix. Our analytical and numerical results reveal that in multi-cell massive
MIMO systems employing matched-filter precoding (1) AN generation is required
to achieve a positive ergodic secrecy rate if the user and the eavesdropper
experience the same path-loss, (2) even with AN generation secure transmission
may not be possible if the number of eavesdropper antennas is too large and not
enough power is allocated to channel estimation, (3) for a given fraction of
power allocated to AN and a given number of users, in case of pilot
contamination, the ergodic secrecy rate is not a monotonically increasing
function of the number of BS antennas, and (4) random AN shaping matrices
provide a favourable performance/complexity tradeoff and are an attractive
alternative to conventional AN shaping matrices