1. Analysis of a Wireless Powered Cooperative Network using a
Hybrid Relay
Introduction
Contact: u5228414@anu.edu.au
Research School of Engineering
ANU College of Engineering & Computer Science
Kazi Ahnaf Ahmed Supervisor: Dr Xiangyun (Sean) Zhou
2nd Conference on Engineering Students Individual Projects
CESIP
October 2015
Eliminating the need for recharging and replacing batteries in
wireless devices has been a long-standing ICT challenge. Wireless
Power Transfer (WPT) promises to be an attractive solution to cut
the last wires connecting mobiles devices to the grid. Recent
advancements in Microwave Power Transmission (MPT) have
made WPT a feasible technology for long range applications. This
research topic analyses a Wireless Powered Communication
(WPCN) powered by MPT technology to the answer the question:
‘How does the performance of a WPCN compare to a conventional
cellular network?’
Previous Work
Methodology
 The E-C protocol is superior to D-C protocol under all tested
scenarios
 Performance of the WPCN drops off significantly after 5-7m
 The WPCN should be implemented in high density this may
require an overhaul of the existing architecture
 Massive MIMO and Small Cell Networks are key enabling
technologies for WPCNs.
Results
The system performance is measured using the average
throughput. The throughput is the rate of successful message
delivery over a communication network. The source is moved
relative to the AP and hybrid relay and the throughput is measured
to determine the range of the WPCN.
The system is optimized for maximum throughput by varying the
energy transfer and power transmission time fractions. The
optimized system is then compared with a conventional cellular
network and the results are used to propose a network
architecture.
Conclusion
 (Chen et al. 2014) introduced a simple wireless powered
cooperative network model. This is used as the starting point to
answer the research question.
 (Huang & Lau 2014) proposes a network architecture of power
beacons overlaid on the existing cellular network.
 The research paper by (Huang & Zhou 2015) discusses key
breakthroughs for WPT including massive MIMO and Small Cell
Networks.
The optimized throughput for the for the Energy Cooperation
Protocol is shown by the surface plot in Figure 4. The
corresponding energy transfer time is illustrated using Figure 5.
Figure 1: System Model (Chen et al. 2014)
Figure 3: Dual-Cooperation ProtocolFigure 2: Energy-Cooperation
Protocol
Figure 4: Maximum Throughput Figure 5: Optimized time fraction
Figure 6: Comparison of system performance for conventional
cellular network and WPCN
Reference
The model by (Chen at al. 2014) shown in Figure 1 is analysed
using the two communication protocols illustrated in Figure 2 and
3. The Access Point (AP) and Hybrid Relay (R) are used to transfer
energy to the Source (S) in the first time instance. In the Energy
Cooperation (E-C) protocol the source transmits information
directly to the AP using the harvested energy. For the Dual
Cooperation (D-C) protocol the source transmits the information
signal through the hybrid relay in addition to the direct path.
Figure 6 below compares the un-optimized and optimized system
protocols with two conventional cellular network protocols.
 Chen, H. et al., 2014. Wireless-Powered Cooperative Communications via a Hybrid Relay. ,
p.5. Available at: http://arxiv.org/abs/1408.4841.
 Huang, K. & Lau, V.K.N., 2014. Realizing wireless power transfer in cellular networks.
Communications (ICC), 2014 IEEE International Conference on, 13(2), pp.5544–5549.
 Huang, K. & Zhou, X., 2015. Cutting the last wires for mobile communications by microwave
power transfer. IEEE Communications Magazine, 53(6), pp.86–93. Available at:
http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=7120022