663 research outputs found
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Wireless Information and Power Transfer in Full-Duplex Systems with Massive Antenna Arrays
We consider a multiuser wireless system with a full-duplex hybrid access
point (HAP) that transmits to a set of users in the downlink channel, while
receiving data from a set of energy-constrained sensors in the uplink channel.
We assume that the HAP is equipped with a massive antenna array, while all
users and sensor nodes have a single antenna. We adopt a time-switching
protocol where in the first phase, sensors are powered through wireless energy
transfer from HAP and HAP estimates the downlink channel of the users. In the
second phase, sensors use the harvested energy to transmit to the HAP. The
downlink-uplink sum-rate region is obtained by solving downlink sum-rate
maximization problem under a constraint on uplink sum-rate. Moreover, assuming
perfect and imperfect channel state information, we derive expressions for the
achievable uplink and downlink rates in the large-antenna limit and approximate
results that hold for any finite number of antennas. Based on these analytical
results, we obtain the power-scaling law and analyze the effect of the number
of antennas on the cancellation of intra-user interference and the
self-interference.Comment: Accepted for the IEEE International Conference on Communications (ICC
2017
Secure Satellite Communication Systems Design with Individual Secrecy Rate Constraints
In this paper, we study multibeam satellite secure communication through
physical (PHY) layer security techniques, i.e., joint power control and
beamforming. By first assuming that the Channel State Information (CSI) is
available and the beamforming weights are fixed, a novel secure satellite
system design is investigated to minimize the transmit power with individual
secrecy rate constraints. An iterative algorithm is proposed to obtain an
optimized power allocation strategy. Moreover, sub-optimal beamforming weights
are obtained by completely eliminating the co-channel interference and nulling
the eavesdroppers' signal simultaneously. In order to obtain jointly optimized
power allocation and beamforming strategy in some practical cases, e.g., with
certain estimation errors of the CSI, we further evaluate the impact of the
eavesdropper's CSI on the secure multibeam satellite system design. The
convergence of the iterative algorithm is proven under justifiable assumptions.
The performance is evaluated by taking into account the impact of the number of
antenna elements, number of beams, individual secrecy rate requirement, and
CSI. The proposed novel secure multibeam satellite system design can achieve
optimized power allocation to ensure the minimum individual secrecy rate
requirement. The results show that the joint beamforming scheme is more
favorable than fixed beamforming scheme, especially in the cases of a larger
number of satellite antenna elements and higher secrecy rate requirement.
Finally, we compare the results under the current satellite air-interface in
DVB-S2 and the results under Gaussian inputs.Comment: 34 pages, 10 figures, 1 table, submitted to "Transactions on
Information Forensics and Security
A Tutorial on Nonorthogonal Multiple Access for 5G and Beyond
Today's wireless networks allocate radio resources to users based on the
orthogonal multiple access (OMA) principle. However, as the number of users
increases, OMA based approaches may not meet the stringent emerging
requirements including very high spectral efficiency, very low latency, and
massive device connectivity. Nonorthogonal multiple access (NOMA) principle
emerges as a solution to improve the spectral efficiency while allowing some
degree of multiple access interference at receivers. In this tutorial style
paper, we target providing a unified model for NOMA, including uplink and
downlink transmissions, along with the extensions tomultiple inputmultiple
output and cooperative communication scenarios. Through numerical examples, we
compare the performances of OMA and NOMA networks. Implementation aspects and
open issues are also detailed.Comment: 25 pages, 10 figure
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