2,854 research outputs found
Energy Harvesting Wireless Communications: A Review of Recent Advances
This article summarizes recent contributions in the broad area of energy
harvesting wireless communications. In particular, we provide the current state
of the art for wireless networks composed of energy harvesting nodes, starting
from the information-theoretic performance limits to transmission scheduling
policies and resource allocation, medium access and networking issues. The
emerging related area of energy transfer for self-sustaining energy harvesting
wireless networks is considered in detail covering both energy cooperation
aspects and simultaneous energy and information transfer. Various potential
models with energy harvesting nodes at different network scales are reviewed as
well as models for energy consumption at the nodes.Comment: To appear in the IEEE Journal of Selected Areas in Communications
(Special Issue: Wireless Communications Powered by Energy Harvesting and
Wireless Energy Transfer
Energy-delay bounds analysis in wireless multi-hop networks with unreliable radio links
Energy efficiency and transmission delay are very important parameters for
wireless multi-hop networks. Previous works that study energy efficiency and
delay are based on the assumption of reliable links. However, the unreliability
of the channel is inevitable in wireless multi-hop networks. This paper
investigates the trade-off between the energy consumption and the end-to-end
delay of multi-hop communications in a wireless network using an unreliable
link model. It provides a closed form expression of the lower bound on the
energy-delay trade-off for different channel models (AWGN, Raleigh flat fading
and Nakagami block-fading) in a linear network. These analytical results are
also verified in 2-dimensional Poisson networks using simulations. The main
contribution of this work is the use of a probabilistic link model to define
the energy efficiency of the system and capture the energy-delay trade-offs.
Hence, it provides a more realistic lower bound on both the energy efficiency
and the energy-delay trade-off since it does not restrict the study to the set
of perfect links as proposed in earlier works
From carbon nanotubes and silicate layers to graphene platelets for polymer nanocomposites
In spite of extensive studies conducted on carbon nanotubes and silicate layers for their polymer-based nanocomposites, the rise of graphene now provides a more promising candidate due to its exceptionally high mechanical performance and electrical and thermal conductivities. The present study developed a facile approach to fabricate epoxy–graphene nanocomposites by thermally expanding a commercial product followed by ultrasonication and solution-compounding with epoxy, and investigated their morphologies, mechanical properties, electrical conductivity and thermal mechanical behaviour. Graphene platelets (GnPs) of 3.5
Wireless Information and Energy Transfer for Two-Hop Non-Regenerative MIMO-OFDM Relay Networks
This paper investigates the simultaneous wireless information and energy
transfer for the non-regenerative multipleinput multiple-output orthogonal
frequency-division multiplexing (MIMO-OFDM) relaying system. By considering two
practical receiver architectures, we present two protocols, time switchingbased
relaying (TSR) and power splitting-based relaying (PSR). To explore the system
performance limit, we formulate two optimization problems to maximize the
end-to-end achievable information rate with the full channel state information
(CSI) assumption. Since both problems are non-convex and have no known solution
method, we firstly derive some explicit results by theoretical analysis and
then design effective algorithms for them. Numerical results show that the
performances of both protocols are greatly affected by the relay position.
Specifically, PSR and TSR show very different behaviors to the variation of
relay position. The achievable information rate of PSR monotonically decreases
when the relay moves from the source towards the destination, but for TSR, the
performance is relatively worse when the relay is placed in the middle of the
source and the destination. This is the first time to observe such a
phenomenon. In addition, it is also shown that PSR always outperforms TSR in
such a MIMO-OFDM relaying system. Moreover, the effect of the number of
antennas and the number of subcarriers are also discussed.Comment: 16 pages, 12 figures, to appear in IEEE Selected Areas in
Communication
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