2,050 research outputs found
Design of a Planar Eleven Antenna for Optimal MIMO Performance as a Wideband Micro Base-station Antenna
A new low-profile planar Eleven antenna is designed for optimal MIMO
performance as a wideband MIMO antenna for micro base-stations in future
wireless communication systems. The design objective has been to optimize both
the reflection coefficient at the input port of the antenna and the 1-bitstream
and 2-bitstream MIMO efficiency of the antenna at the same time, in both the
Rich Isotropic MultiPath (RIMP) and Random Line-of-Sight (Random-LOS)
environments. The planar Eleven antenna can be operated in 2-, 4-, and 8-port
modes with slight modifications. The optimization is performed using genetic
algorithms. The effects of polarization deficiencies and antenna total embedded
efficiency on the MIMO performance of the antenna are further studied. A
prototype of the antenna has been fabricated and the design has been verified
by measurements against the simulations.Comment: 7 pages, 15 figures, 15 reference
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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