212 research outputs found
Amplify-and-Forward Full-Duplex Relay with Power Splitting-Based SWIPT
This paper proposes a virtual harvest-transmit model and a
harvest-transmit-store model for amplify-and-forward full-duplex relay (FDR)
networks with power splitting-based simultaneous wireless information and power
transfer. The relay node employs a battery group consisting of two rechargeable
batteries. By switching periodically between two batteries for charging and
discharging in two consecutive time slots of each transmission block, all the
harvested energy in each block has been applied for full duplex transmission in
the virtual harvest-transmit model. By employing energy scheduling, the relay
node switches among the harvesting, relaying, harvesting-relaying, and idle
behaviors at a block level, so that a part of the harvested energy in a block
can be scheduled for future usage in the harvest-transmit-store model. A greedy
switching policy is designed to implement the harvest-transmit-store model,
where the FDR node transmits when its residual energy ensures decoding at the
destination. Numerical results verify the outage performance of the proposed
schemes.Comment: 4 pages, submit to a conferenc
Energy Efficient Precoding Design for SWIPT in MIMO Two-Way Relay Networks
In this paper, we study the energy efficiency (EE) maximization problem in
multiple-input multiple-output (MIMO) two-way relay networks with simultaneous
wireless information and power transfer (SWIPT). The network consists of a
multiple-antenna amplify-and-forward relay node which provides bidirectional
communications between two multiple-antenna transceiver nodesComment: 16 pages, 6 figures, to appear in IEEE Transactions on Vehicular
Technolog
Wireless Information and Power Transfer for Multi-Relay Assisted Cooperative Communication
In this paper, we consider simultaneous wireless information and power
transfer (SWIPT) in multi-relay assisted two-hop relay system, where multiple
relay nodes simultaneously assist the transmission from source to destination
using the concept of distributed space-time coding. Each relay applies power
splitting protocol to coordinate the received signal energy for information
decoding and energy harvesting. The optimization problems of power splitting
ratios at the relays are formulated for both decode-and-forward (DF) and
amplify-and-forward (AF) relaying protocols. Efficient algorithms are proposed
to find the optimal solutions. Simulations verify the effectiveness of the
proposed schemes.Comment: To be published in IEEE Communications Letter
DEBIT: Distributed Energy Beamforming and Information Transfer for Multiway Relay Networks
In this paper, we propose a new distributed energy beamforming and
information transfer (DEBIT) scheme for realizing simultaneous wireless
information and power transfer (SWIPT) in multiway relay networks (MWRNs),
where multiple single-antenna users exchange information via an
energy-constrained single-antenna relay node. We investigate the optimal
transceiver designs to maximize the achievable sum-rate or the harvested power.
The resultant sum-rate maximization problem is non-convex and the global
optimal solution can be obtained through a three-dimensional search in
combination with conventional convex optimization. To reduce the computation
complexity, a suboptimal DEBIT scheme is also proposed, for which the
optimization problem becomes linear programming. The achievable sum-rate
performance is analyzed and a closed-form lower bound is derived for the MWRN
with a large number of users. Furthermore, we consider the harvested-power
maximization problem under a target sum-rate constraint, and derive a lower
bound of the average harvested power for MWRNs with a large number of users.
Numerical results show that the DEBIT scheme significantly outperforms the
conventional SWIPT and the derived lower bounds are tight.Comment: 8 page
Outage analysis in two-way communication with RF energy harvesting relay and co-channel interference
The study of relays with the scope of energy-harvesting (EH) looks
interesting as a means of enabling sustainable, wireless communication without
the need to recharge or replace the battery driving the relays. However,
reliability of such communication systems becomes an important design challenge
when such relays scavenge energy from the information bearing RF signals
received from the source, using the technique of simultaneous wireless
information and power transfer (SWIPT). To this aim, this work studies
bidirectional communication in a decode-and-forward (DF) relay assisted
cooperative wireless network in presence of co-channel interference (CCI). In
order to quantify the reliability of the bidirectional communication systems, a
closed form expression for the outage probability of the system is derived for
both power splitting (PS) and time switching (TS) mode of operation of the
relay. Simulation results are used to validate the accuracy of our analytical
results and illustrate the dependence of the outage probability on various
system parameters, like PS factor, TS factor, and distance of the relay from
both the users. Results of performance comparison between PS relaying (PSR) and
TS relaying (TSR) schemes are also presented. Besides, simulation results are
also used to illustrate the spectral-efficiency and the energy-efficiency of
the proposed system. The results show that, both in terms of spectral
efficiency and the energy-efficiency, the two-way communication system in
presence of moderate CCI power, performs better than the similar system without
CCI. Additionally, it is also found that PSR is superior to TSR protocol in
terms of peak energy-efficiency.Comment: 12 Pages, 9 Figures, Communicated wor
Joint resource allocation in SWIPT-based multi-antenna decode-and-forward relay networks
In this paper, we consider relay-assisted simultaneous wireless information
and power transfer (SWIPT) for two-hop cooperative transmission, where a
half-duplex multi-antenna relay adopts decode-and-forward (DF) relaying
strategy for information forwarding. The relay is assumed to be energy-free and
needs to harvest energy from the source node. By embedding power splitting (PS)
at each relay antenna to coordinate the received energy and information, joint
problem of determining PS ratios and power allocation at the multi-antenna
relay node is formulated to maximize the end-to-end achievable rate. We show
that the multi-antenna relay is equivalent to a virtual single-antenna relay in
such a SWIPT system, and the problem is optimally solved with closed-form. To
reduce the hardware cost of the PS scheme, we further propose the antenna
clustering scheme, where the multiple antennas at the relay are partitioned
into two disjoint groups which are exclusively used for information decoding
and energy harvesting, respectively. Optimal clustering algorithm is first
proposed but with exponential complexity. Then a greedy clustering algorithms
is introduced with linear complexity and approaching to the optimal
performance. Several valuable insights are provided via theoretical analysis
and simulation results.Comment: To appear in IEEE TV
Interference Alignment with Power Splitting Relays in Multi-User Multi-Relay Networks
In this paper, we study a multi-user multi-relay interference-channel
network, where energy-constrained relays harvest energy from sources' radio
frequency (RF) signals and use the harvested energy to forward the information
to destinations. We adopt the interference alignment (IA) technique to address
the issue of interference, and propose a novel transmission scheme with the IA
at sources and the power splitting (PS) at relays. A distributed and iterative
algorithm to obtain the optimal PS ratios is further proposed, aiming at
maximizing the sum rate of the network. The analysis is then validated by
simulation results. Our results show that the proposed scheme with the optimal
design significantly improves the performance of the network.Comment: 6 pages, 6 figures, to appear in Proc. VTC Fall, Toronto, Canad
Secure SWIPT for Directional Modulation Aided AF Relaying Networks
Secure wireless information and power transfer based on directional
modulation is conceived for amplify-and-forward (AF) relaying networks.
Explicitly, we first formulate a secrecy rate maximization (SRM) problem, which
can be decomposed into a twin-level optimization problem and solved by a
one-dimensional (1D) search and semidefinite relaxation (SDR) technique. Then
in order to reduce the search complexity, we formulate an optimization problem
based on maximizing the signal-to-leakage-AN-noise-ratio (Max-SLANR) criterion,
and transform it into a SDR problem. Additionally, the relaxation is proved to
be tight according to the classic Karush-Kuhn-Tucker (KKT) conditions. Finally,
to reduce the computational complexity, a successive convex approximation (SCA)
scheme is proposed to find a near-optimal solution. The complexity of the SCA
scheme is much lower than that of the SRM and the Max-SLANR schemes. Simulation
results demonstrate that the performance of the SCA scheme is very close to
that of the SRM scheme in terms of its secrecy rate and bit error rate (BER),
but much better than that of the zero forcing (ZF) scheme
Performance of SWIPT-based Differential Amplify-and-Forward Relaying with Direct Link
A novel asymptotic closed-form probability density function (pdf) of the
two-hop (TH) link is derived for a simultaneous wireless information and power
transfer based differential amplify-and-forward system. Based on the pdf,
asymptotic closed-form average bit-error rate expressions of the single TH link
and the TH link with direct link combined with a linear combining scheme are
both derived. Monte Carlo simulations verify the analytical expressions.Comment: 12 pages, 3 figures, submitted for possible publicatio
Joint Transceiver Design Algorithms for Multiuser MISO Relay Systems with Energy Harvesting
In this paper, we investigate a multiuser relay system with simultaneous
wireless information and power transfer. Assuming that both base station (BS)
and relay station (RS) are equipped with multiple antennas, this work studies
the joint transceiver design problem for the BS beamforming vectors, the RS
amplify-and-forward transformation matrix and the power splitting (PS) ratios
at the single-antenna receivers. Firstly, an iterative algorithm based on
alternating optimization (AO) and with guaranteed convergence is proposed to
successively optimize the transceiver coefficients. Secondly, a novel design
scheme based on switched relaying (SR) is proposed that can significantly
reduce the computational complexity and overhead of the AO based designs while
maintaining a similar performance. In the proposed SR scheme, the RS is
equipped with a codebook of permutation matrices. For each permutation matrix,
a latent transceiver is designed which consists of BS beamforming vectors,
optimally scaled RS permutation matrix and receiver PS ratios. For the given
CSI, the optimal transceiver with the lowest total power consumption is
selected for transmission. We propose a concave-convex procedure based and
subgradient-type iterative algorithms for the non-robust and robust latent
transceiver designs. Simulation results are presented to validate the
effectiveness of all the proposed algorithms
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