283 research outputs found
Fundamental Limits of Spectrum Sharing for NOMA-based Cooperative Relaying
Non-orthogonal multiple access (NOMA) and spectrum sharing (SS) are two
emerging multiple access technologies for efficient spectrum utilization in the
fifth-generation (5G) wireless communications standard. In this paper, we
present a closed-form analysis of the average achievable sum-rate and outage
probability for a NOMA-based cooperative relaying system (CRS) in an underlay
spectrum sharing scenario. We consider a peak interference constraint, where
the interference inflicted by the secondary (unlicensed) network on the
primary-user (licensed) receiver (PU-Rx) should be less than a predetermined
threshold. We show that the CRS-NOMA outperforms the CRS with conventional
orthogonal multiple access (OMA) for large values of peak interference power at
the PU-Rx.Comment: 3 figures, Accepted for presentation in GLOBECOM-NOMAT5G workshop,
Abu Dhabi, 201
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
Hardware and Interference Limited Cooperative CR-NOMA Networks under Imperfect SIC and CSI
The conflation of cognitive radio (CR) and nonorthogonal multiple access
(NOMA) concepts is a promising approach to fulfil the massive connectivity
goals of future networks given the spectrum scarcity. Accordingly, this letter
investigates the outage performance of imperfect cooperative CR-NOMA networks
under hardware impairments and interference. Our analysis is involved with the
derivation of the end-to-end outage probability (OP) for secondary NOMA users
by accounting for imperfect channel state information (CSI), as well as the
residual interference caused by successive interference cancellation (SIC)
errors and coexisting primary/secondary users. The numerical results validated
by Monte Carlo simulations show that CR-NOMA network provides a superior outage
performance over orthogonal multiple access. As imperfections become more
significant, CR-NOMA is observed to deliver relatively poor outage performance.Comment: 5 pages, 4 figure
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