M2WPT - a large-scale Multi-antenna Multi-sine Wireless Power Transfer architecture

Lead Research Organisation: Imperial College London
Department Name: Electrical and Electronic Engineering

Abstract

Wireless power transfer (WPT) via radio-frequency (RF) radiation has long been regarded as a possibility for energising low-power devices in the internet of things. It is, however, not until recently that WPT has become recognised as feasible, due to reductions in power requirements of electronics. Far-field WPT using RF could be used for long range power delivery to increase user convenience. In the same way as wireless disrupted communication, WPT using RF is expected to disrupt the delivery of energy.
The real challenge with far field WPT is to find ways to increase the DC power level at the energy harvester output without increasing the transmit power, and to ensure that sufficient range between transmitter and receiver can be achieved.
The project relies on the observation that far-field WPT RF-to-DC conversion efficiency is a function of the rectenna design but also of its input waveform. A proper design of far-field WPT therefore requires a complete transmitter-receiver optimization rather than just the receiver (rectenna) design. Unfortunately state of the art waveforms have been shown partially disappointing for far-field WPT. The fundamental question behind the project is "can we design a disruptive but practical WPT transceiver architecture to make wireless power transfer a reality at distances of tens (if not more) of meters within regulated transmit power levels?"
This visionary project, conducted at Imperial College London, will uniquely leverage signal processing tools to tackle a problem commonly investigated by the RF community. Motivated by recent results by the PI and Co-I and leveraging a unique set of complementary skills on multi-antenna signal processing (Clerckx) and WPT/rectenna design (Mitcheson), the project will design and show the feasibility of a disruptive M2WPT architecture based on optimized, adaptive and reliable large-scale multi-antenna multi-sine waveforms for single-user and multi-user scenarios, and identify its potential for far-field WPT. Thinking big, we advocate in this project that M2WPT will be to WPT what massive MIMO is to communication. M2WPT will enable highly efficient far-field WPT delivering sufficient power at long range for a wide range of applications.
To put together this novel M2WPT solution in a credible fashion, this project focuses on 1) designing and modelling the energy harvester, 2) designing large-scale multi-sine multi-antenna waveforms for single and multi-user scenarios, 3) demonstrate the feasibility through experiment and measurement.
The project will be performed in partnership with two leaders in equipment manufacturing and WPT standardization (Toshiba and Keysight), two well-established academic/research centres active in WPT (KULeuven and Eindhoven/IMEC) and the UK Office of the Chief Science Adviser. The project demands a strong and inter-disciplinary track record in microwave theory and techniques, circuit design, optimization theory, multi-antenna signal processing, wireless communication and it is to be conducted in a unique research group with a right mix of theoretical and practical skills. With the above and given the novelty and originality of the topic, the research outcomes will be of considerable value to transform the future of wireless networks supplied by remote wireless charging and give the industry a fresh and timely insight into the development of highly efficient remote wireless charging, advancing UK's research profile of wireless power in the world. Its success would radically change the design of radiative WPT, have a tremendous impact on standardization, and applications in a large number of sectors including building automation, healthcare, telecommunications, ICT, structural monitoring, consumer electronics.

Planned Impact

Besides the academic beneficiaries, the project will benefit a much wider audience and have potential economic and societal impacts:
1) Wireless networks are expected to have applications in developed and emerging markets and a large number of sectors, e.g. building automation, healthcare (health monitoring), telecommunications, smart grid, structural monitoring, consumer electronics, military, etc. All those new applications will in the long term enhance the economic competitiveness of the UK and the quality of life of its residents. Reliable power supply remains a significant barrier to the adoption of the internet of things.
2) Given the enormous interest for wireless power and high speed communications (as evidenced by WPC, PMA, A4WP, 3GPP and IEEE standards), the project has a bright future to benefit the industry sector active in the area of wireless power transfer, energy harvesting, communication equipment manufacturing and standards. By benefiting from our industry partners Toshiba and Keysight, Toshiba's involvements in standards and by Dr. Clerckx's general experience in standardization, the project is expected to lead to several contributions in early standards creation on radiative WPT.
3) Supported by the UK Home Office (Office of the Chief Science Adviser), the project will also benefit the regulators and actors involved with policy implementations in the wireless sector and give them the opportunity to understand the benefits and feasibility of far-field WPT.
4) It is an absolute requirement to understand how to reduce ambient RF pollution and make our network greener and more energy efficient. Any additional transmission for the purposes of power transfer must not swamp existing communication systems, or cause them to boost their transmit power, in turn causing them to need additional power supply. Power transmission in an existing communication band would cause interference, but communication receivers could reject the noise from the power transmission due to the deterministic nature of the multi-sine, or alternatively the power transmission could be done in a separate band. Ultimately, M2WPT based on large scale multi-antenna and multi-sine waveforms will make a better use of the transmit power, and achieve significantly higher RF to DC conversion efficiency allowing lower transmit power than conventional approaches and could enable larger scale energy savings through deployment of the internet of things. The project will therefore also benefit researchers, policy makers, and government agencies active in understanding how technologies could be designed to make our environment greener.

Publications

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Clerckx B (2017) Low-Complexity Adaptive Multisine Waveform Design for Wireless Power Transfer in IEEE Antennas and Wireless Propagation Letters

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Clerckx B (2019) Guest Editorial Wireless Transmission of Information and Power-Part II in IEEE Journal on Selected Areas in Communications

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Clerckx B (2019) Guest Editorial Wireless Transmission of Information and Power-Part I in IEEE Journal on Selected Areas in Communications

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Huang Y (2017) Large-Scale Multiantenna Multisine Wireless Power Transfer in IEEE Transactions on Signal Processing

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Huang Y (2018) Waveform Design for Wireless Power Transfer With Limited Feedback in IEEE Transactions on Wireless Communications

 
Description New RF and signal designs for wireless power transfer and for wireless information and power transfer.
Exploitation Route we are currently prototyping and experimenting the system.
The biggest part has been validated and transfer of technology to industry is on-going.
Sectors Digital/Communication/Information Technologies (including Software),Electronics

 
Description on-going discussions with industry partners. Some transfer of technology is on-going with a major telecommunication manufacturer
Sector Digital/Communication/Information Technologies (including Software),Electronics
Impact Types Economic

 
Description Collaboration with HKU on wireless power 
Organisation University of Hong Kong
Country Hong Kong 
Sector Academic/University 
PI Contribution visit at HKU in 2016 and collaboration since then.
Collaborator Contribution visit at HKU in 2016 and collaboration since then.
Impact B. Clerckx, Z. Bayani Zawawi and K. Huang "Wirelessly Powered Backscatter Communications: Waveform Design and SNR-Energy Tradeoff" IEEE Communication Letters, vol 21, no 10, pp 2234-2237, Oct 2017. One book chapter is currently being written.
Start Year 2016
 
Description Collaboration with KULeuven on wireless power 
Organisation University of Leuven
Country Belgium 
Sector Academic/University 
PI Contribution initiate collaboration with KULeuven to experiment wireless power transfer and wireless information and power transfer using large antenna arrays.
Collaborator Contribution on-going collaboration
Impact no concrete outputs. experimentation considered was found too complex to pursue.
Start Year 2017
 
Description Collaboration with NUS 
Organisation National University of Singapore
Country Singapore 
Sector Academic/University 
PI Contribution Research stay at NUS in July 2015 with on-going collaboration since then.
Collaborator Contribution Research stay at NUS in July 2015 with on-going collaboration since then.
Impact 1) An invited paper Y. Zeng, B. Clerckx and R. Zhang, "Communications and Signals Design for Wireless Power Transmission" accepted to IEEE Trans. on Comm, to be published in 2017 is an output of the collaboration. 2) Preparation of a special issue on wireless information and power transmission in IEEE Journal on Selected Areas in Communications, and following publications: B. Clerckx, R. Zhang, R. Schober, D. W. K. Ng, D. I. Kim, and H. V. Poor, "Guest Editorial Wireless Transmission of Information and Power-Part I," IEEE Journal on Selected Areas in Communications, vol. 37, no. 1, pp. 1-3, Jan 2019. B. Clerckx, R. Zhang, R. Schober, D. W. K. Ng, D. I. Kim, and H. V. Poor, "Fundamentals of Wireless Information and Power Transfer: From RF Energy Harvester Models to Signal and System Designs," IEEE Journal on Selected Areas in Communications, vol. 37, no. 1, pp. 4-33, Jan 2019. B. Clerckx, R. Zhang, R. Schober, D. W. K. Ng, D. I. Kim, and H. V. Poor, "Guest Editorial Wireless Transmission of Information and Power-Part II," IEEE Journal on Selected Areas in Communications, Feb 2019.
Start Year 2015
 
Title A method for designing signal waveforms 
Description This is a patent application that originates in 2016 from some research following-up this award. The patent application is about the design of low complexity waveforms for wireless power transfer. 
IP Reference GB1618442.6 
Protection Patent application published
Year Protection Granted
Licensed No
Impact Discussions with companies for licensing are on-going.
 
Title A method of inducing amplitude fluctuations in a wireless power transfer channel 
Description Wireless Power Transfer (WPT) via radio-frequency radiation is nowadays regarded as a feasible technology for energising low-power devices in Internet-of-Things (IoT) applications. The major challenge with WPT is to find ways to increase the end-to-end power transfer efficiency, or equivalently the DC power level at the output of the energy harvester (so-called rectenna) for a given transmit power. To that end, the traditional line of research in the RF literature has been devoted to the design of efficient rectennas, but a new line of research on communications and signals design for WPT has emerged recently in the communication literature. Various WPT signal strategies have been developed to boost the harvested DC power. A conventional technique is to use multiple transmit antennas and beamforming so as to increase the RF input power to the energy harvester. Beamforming relies on channel state information at the transmitter (CSIT). We here develop a new form of signal design for WPT, denoted as Transmit Diversity, that relies on multiple dumb antennas at the transmitter to induce fast fluctuations of the wireless channel. Those fluctuations boost the RF-to-DC conversion efficiency thanks to the energy harvester nonlinearity. In contrast with beamforming, Transmit Diversity does not rely on CSIT. The proposed strategy is particularly suited for massive IoT deployments for which CSIT acquisition is unpractical. 
IP Reference GB1813778.6 
Protection Patent application published
Year Protection Granted 2018
Licensed No
Impact currently under discussion with various companies.
 
Description Keynote at School of the Wireless Power Week 2019, London, UK 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact The talk was about "Optimize, Learn and Prototype Wireless Communications and Power Transfer", delivered at the School of the Wireless Power Week 2019, London, UK.
Year(s) Of Engagement Activity 2019
URL https://www.wpw2019.org/school.htm
 
Description Organizer of a special issue in IEEE Journal of Selected Areas in Communications 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Close to 100 journal papers were submitted to this special issue, and about 30 papers were accepted and published in those different issues published in Jan 2019 and Feb 2019.
Year(s) Of Engagement Activity 2019
 
Description Tutorial at European Conference on Antennas and Propagation (EUCAP) 2018. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Tutorial on "Far-Field wireless power transmission: RF, signal and system designs," European Conference on Antennas and Propagation (EUCAP) 2018.
Year(s) Of Engagement Activity 2018
URL https://www.eucap2018.org/conference/short-courses
 
Description Tutorial on "Communication and Signal Processing Advances in Wireless Power Transmission," IEEE/CIC International Conference on Communications in China (ICCC) 2017, Qingdao, China. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact tutorial to highlight the recent outcomes of the project
Year(s) Of Engagement Activity 2017
URL http://iccc2017.ieee-iccc.org/program/tutorials/
 
Description Tutorial on "Emerging Topics in 5G Networks: Simultaneous Wireless Information and Energy Transfer" European Signal Processing Conference EUSIPCO 2017, Greece. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact tutorial in academic conference to highlight the outcomes of the project
Year(s) Of Engagement Activity 2017
 
Description Tutorial on "Emerging Topics in 5G Networks: Simultaneous Wireless Information and Energy Transfer" IEEE Globecom 2017, Singapore. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact tutorial in academic conference to highlight the recent outcomes of the project
Year(s) Of Engagement Activity 2017
URL http://globecom2017.ieee-globecom.org/content/tutorials#Tut09