342 research outputs found
Energy Harvesting Enabled Cooperative Networks Resource Allocation Techniques, Protocol Design And Performance Analysis
In In wireless cooperative communication networks, cooperative relaying techniques can be employed to mitigate fading and attenuation problems by
positioning relay nodes between a transmitter and a receiver. Therefore, network performance such as efficiency, throughput, and reliability can be improved. However,
energy-constrained wireless cooperative relay nodes have a limited viable lifetime,which cannot sustain steady network connectivity, thereby making reliable
communication difficult. Recently, energy harvesting (EH) via radio frequency (RF)signals appears to be a solution for sustaining the lifetime of the wireless cooperative
relay nodes. In the past years, researchers have proposed some resource allocation techniques and protocols for simultaneous wireless information and power transfer
(SWIPT) in the wireless cooperative communication networks. Nevertheless, there are still a lot of challenges being faced by the researchers to achieve an efficient SWIPT
in such network. In this work, a new energy saving (ES) resource allocation technique
is proposed for RF-EH enabled cooperative networks by adopting time switching
relaying (TSR) and power splitting relaying (PSR) protocols. This is based on the
assumption that the relay node uses a certain proportion of the harvested power in the
current transmission block and then save the remaining portion for the next transmission block. Unlike the previous works, in that the resource allocation
techniques in RF-EH enabled cooperative networks have been considered under the assumption that the energy-constrained relay must utilize all of its harvested power in
each transmission block. The proposed ES technique is then optimized by considering
the optimization problems. Then, the scenario of EH-enabled cooperative network with the presence of an interfering transmitter is considered. A hybridized power-time
splitting based relaying (HPTSR) protocol is also proposed with amplified-andforward (AF) and decode-and-forward (DF) relaying techniques by introducing a
channel-based and power-time splitter into the relay receiver architecture are analyzed.
Numerical results revealed that the proposed ES-TSR and ES-PSR protocols outperformed the existing TSR and PSR protocols with an energy efficiency gain of
13.87 % and 8.31 %, respectively, particularly, when the number of transmission block
L 10. These results show that the proposed ES resource allocation technique is more
energy efficient than the existing ones. At the optimal throughput value, the proposed
AF HPTSR protocol outperformed the existing AF PSR, TSR, and time power switching relaying (TPSR) based protocols with a throughput gain of 54.18 %, 72.31
%, and 10.47 %, respectively. The proposed DF HPTSR protocol showed a performance gain of 2.81 % over the proposed AF HPTSR protocol. These results
show that the proposed AF or DF HPTSR protocol can achieve a better throughput performance over the existing protocols, especially at high signal-to-noise ratio
Rate-Energy Balanced Precoding Design for SWIPT based Two-Way Relay Systems
Simultaneous wireless information and power transfer (SWIPT) technique is a
popular strategy to convey both information and RF energy for harvesting at
receivers. In this regard, we consider a two-way relay system with multiple
users and a multi-antenna relay employing SWIPT strategy, where splitting the
received signal leads to a rate-energy trade-off. In literature, the works on
transceiver design have been studied using computationally intensive and
suboptimal convex relaxation based schemes. In this paper, we study the
balanced precoder design using chordal distance (CD) decomposition, which
incurs much lower complexity, and is flexible to dynamic energy requirements.
It is analyzed that given a non-negative value of CD, the achieved harvested
energy for the proposed balanced precoder is higher than that for the perfect
interference alignment (IA) precoder. The corresponding loss in sum rates is
also analyzed via an upper bound. Simulation results add that the IA schemes
based on mean-squared error are better suited for the SWIPT maximization than
the subspace alignment-based methods.Comment: arXiv admin note: text overlap with arXiv:2101.1216
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