417 research outputs found
Opportunistic Collaborative Beamforming with One-Bit Feedback
An energy-efficient opportunistic collaborative beamformer with one-bit
feedback is proposed for ad hoc sensor networks over Rayleigh fading channels.
In contrast to conventional collaborative beamforming schemes in which each
source node uses channel state information to correct its local carrier offset
and channel phase, the proposed beamforming scheme opportunistically selects a
subset of source nodes whose received signals combine in a quasi-coherent
manner at the intended receiver. No local phase-precompensation is performed by
the nodes in the opportunistic collaborative beamformer. As a result, each node
requires only one-bit of feedback from the destination in order to determine if
it should or shouldn't participate in the collaborative beamformer. Theoretical
analysis shows that the received signal power obtained with the proposed
beamforming scheme scales linearly with the number of available source nodes.
Since the the optimal node selection rule requires an exhaustive search over
all possible subsets of source nodes, two low-complexity selection algorithms
are developed. Simulation results confirm the effectiveness of opportunistic
collaborative beamforming with the low-complexity selection algorithms.Comment: Proceedings of the Ninth IEEE Workshop on Signal Processing Advances
in Wireless Communications, Recife, Brazil, July 6-9, 200
Recent Advances in Joint Wireless Energy and Information Transfer
In this paper, we provide an overview of the recent advances in
microwave-enabled wireless energy transfer (WET) technologies and their
applications in wireless communications. Specifically, we divide our
discussions into three parts. First, we introduce the state-of-the-art WET
technologies and the signal processing techniques to maximize the energy
transfer efficiency. Then, we discuss an interesting paradigm named
simultaneous wireless information and power transfer (SWIPT), where energy and
information are jointly transmitted using the same radio waveform. At last, we
review the recent progress in wireless powered communication networks (WPCN),
where wireless devices communicate using the power harvested by means of WET.
Extensions and future directions are also discussed in each of these areas.Comment: Conference submission accepted by ITW 201
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
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