3,134 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
Resource Allocation for Secure Gaussian Parallel Relay Channels with Finite-Length Coding and Discrete Constellations
We investigate the transmission of a secret message from Alice to Bob in the
presence of an eavesdropper (Eve) and many of decode-and-forward relay nodes.
Each link comprises a set of parallel channels, modeling for example an
orthogonal frequency division multiplexing transmission. We consider the impact
of discrete constellations and finite-length coding, defining an achievable
secrecy rate under a constraint on the equivocation rate at Eve. Then we
propose a power and channel allocation algorithm that maximizes the achievable
secrecy rate by resorting to two coupled Gale-Shapley algorithms for stable
matching problem. We consider the scenarios of both full and partial channel
state information at Alice. In the latter case, we only guarantee an outage
secrecy rate, i.e., the rate of a message that remains secret with a given
probability. Numerical results are provided for Rayleigh fading channels in
terms of average outage secrecy rate, showing that practical schemes achieve a
performance quite close to that of ideal ones
Achievable Sum Rates of Half- and Full-Duplex Bidirectional OFDM Communication Links
While full-duplex (FD) transmission has the potential to double the system
capacity, its substantial benefit can be offset by the self-interference (SI)
and non-ideality of practical transceivers. In this paper, we investigate the
achievable sum rates (ASRs) of half-duplex (HD) and FD transmissions with
orthogonal frequency division multiplexing (OFDM), where the non-ideality is
taken into consideration. Four transmission strategies are considered, namely
HD with uniform power allocation (UPA), HD with non-UPA (NUPA), FD with UPA,
and FD with NUPA. For each of the four transmission strategies, an optimization
problem is formulated to maximize its ASR, and a (suboptimal/optimal) solution
with low complexity is accordingly derived. Performance evaluations and
comparisons are conducted for three typical channels, namely symmetric
frequency-flat/selective and asymmetric frequency-selective channels. Results
show that the proposed solutions for both HD and FD transmissions can achieve
near optimal performances. For FD transmissions, the optimal solution can be
obtained under typical conditions. In addition, several observations are made
on the ASR performances of HD and FD transmissions.Comment: To appear in IEEE TVT. This paper solves the problem of sum
achievable rate optimization of bidirectional FD OFDM link, where joint time
and power allocation is involve
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