1,139 research outputs found
Wireless-Powered Communication Assisted by Two-Way Relay with Interference Alignment Underlaying Cognitive Radio Network
This study investigates the outage performance of an under-laying
wireless-powered secondary system that reuses the primary users (PU) spectrum
in a multiple-input multiple-output (MIMO) cognitive radio (CR) network. Each
secondary user (SU) harvests energy and receives information simultaneously by
applying power splitting (PS) protocol. The communication between SUs is aided
by a two-way (TW) decode and forward (DF) relay. We formulate a problem to
design the PS ratios at SUs, the power control factor at the secondary relay,
and beamforming matrices at all nodes to minimize the secondary network's
outage probability. To address this problem, we propose a two-step solution.
The first step establishes closedform expressions for the PS ratios at each SU
and secondary relay's power control factor. Furthermore, in the second step,
interference alignment (IA) is used to design proper precoding and decoding
matrices for managing the interference between secondary and primary networks.
We choose IA matrices based on the minimum mean square error (MMSE) iterative
algorithm. The simulation results demonstrate a significant decrease in the
outage probability for the proposed scheme compared to the benchmark schemes,
with an average reduction of more than two orders of magnitude achieved
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Application of Smart Antenna Technologies in Simultaneous Wireless Information and Power Transfer
Simultaneous wireless information and power transfer (SWIPT) is a promising
solution to increase the lifetime of wireless nodes and hence alleviate the
energy bottleneck of energy constrained wireless networks. As an alternative to
conventional energy harvesting techniques, SWIPT relies on the use of radio
frequency signals, and is expected to bring some fundamental changes to the
design of wireless communication networks. This article focuses on the
application of advanced smart antenna technologies, including multiple-input
multiple-output and relaying techniques, to SWIPT. These smart antenna
technologies have the potential to significantly improve the energy efficiency
and also the spectral efficiency of SWIPT. Different network topologies with
single and multiple users are investigated, along with some promising solutions
to achieve a favorable trade-off between system performance and complexity. A
detailed discussion of future research challenges for the design of SWIPT
systems is also provided
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