5,548 research outputs found
Capacity Theorems for the Fading Interference Channel with a Relay and Feedback Links
Handling interference is one of the main challenges in the design of wireless
networks. One of the key approaches to interference management is node
cooperation, which can be classified into two main types: relaying and
feedback. In this work we consider simultaneous application of both cooperation
types in the presence of interference. We obtain exact characterization of the
capacity regions for Rayleigh fading and phase fading interference channels
with a relay and with feedback links, in the strong and very strong
interference regimes. Four feedback configurations are considered: (1) feedback
from both receivers to the relay, (2) feedback from each receiver to the relay
and to one of the transmitters (either corresponding or opposite), (3) feedback
from one of the receivers to the relay, (4) feedback from one of the receivers
to the relay and to one of the transmitters. Our results show that there is a
strong motivation for incorporating relaying and feedback into wireless
networks.Comment: Accepted to the IEEE Transactions on Information Theor
On the cognitive interference channel with causal unidirectional destination cooperation
In previous works, the cognitive interference channel with unidirectional destination cooperation has been studied. In this model, the cognitive receiver acts as a relay of the primary user's message, and its operation is assumed to be strictly causal. In this letter, we study the same channel model with a causal rather than a strictly causal relay, i.e., the relay's transmit symbol depends not only on its past but also on its current received symbol. We propose an outer bound for the discrete memoryless channel, which is later used to compute an outer bound for the Gaussian channel. We also propose an achievable scheme based on instantaneous amplify-and-forward relaying that meets the outer bound in the very strong interference regime
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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