668 research outputs found
Distributed MAC Protocol Supporting Physical-Layer Network Coding
Physical-layer network coding (PNC) is a promising approach for wireless
networks. It allows nodes to transmit simultaneously. Due to the difficulties
of scheduling simultaneous transmissions, existing works on PNC are based on
simplified medium access control (MAC) protocols, which are not applicable to
general multi-hop wireless networks, to the best of our knowledge. In this
paper, we propose a distributed MAC protocol that supports PNC in multi-hop
wireless networks. The proposed MAC protocol is based on the carrier sense
multiple access (CSMA) strategy and can be regarded as an extension to the IEEE
802.11 MAC protocol. In the proposed protocol, each node collects information
on the queue status of its neighboring nodes. When a node finds that there is
an opportunity for some of its neighbors to perform PNC, it notifies its
corresponding neighboring nodes and initiates the process of packet exchange
using PNC, with the node itself as a relay. During the packet exchange process,
the relay also works as a coordinator which coordinates the transmission of
source nodes. Meanwhile, the proposed protocol is compatible with conventional
network coding and conventional transmission schemes. Simulation results show
that the proposed protocol is advantageous in various scenarios of wireless
applications.Comment: Final versio
Relay Selection with Network Coding in Two-Way Relay Channels
In this paper, we consider the design of joint network coding (NC)and relay
selection (RS) in two-way relay channels. In the proposed schemes, two users
first sequentially broadcast their respective information to all the relays. We
propose two RS schemes, a single relay selection with NC and a dual relay
selection with NC. For both schemes, the selected relay(s) perform NC on the
received signals sent from the two users and forward them to both users. The
proposed schemes are analyzed and the exact bit error rate (BER) expressions
are derived and verified through Monte Carlo simulations. It is shown that the
dual relay selection with NC outperforms other considered relay selection
schemes in two-way relay channels. The results also reveal that the proposed NC
relay selection schemes provide a selection gain compared to a NC scheme with
no relay selection, and a network coding gain relative to a conventional relay
selection scheme with no NC.Comment: 11 pages, 5 figure
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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