698 research outputs found
A Novel Network NOMA Scheme for Downlink Coordinated Three-Point Systems
In this paper, we propose a network non-orthogonal multiple access (N-NOMA)
technique for the downlink coordinated multipoint (CoMP) communication scenario
of a cellular network, with randomly deployed users. In the considered N-NOMA
scheme, superposition coding (SC) is employed to serve cell-edge users as well
as users close to base stations (BSs) simultaneously, and distributed analog
beamforming by the BSs to meet the cell-edge user's quality of service (QoS)
requirements. The combination of SC and distributed analog beamforming
significantly complicates the expressions for the
signal-to-interference-plus-noise ratio (SINR) at the reveiver, which makes the
performance analysis particularly challenging. However, by using rational
approximations, insightful analytical results are obtained in order to
characterize the outage performance of the considered N-NOMA scheme. Computer
simulation results are provided to show the superior performance of the
proposed scheme as well as to demonstrate the accuracy of the analytical
results
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
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