TY - JOUR
T1 - Wireless Information and Power Transfer
T2 - Nonlinearity, Waveform Design, and Rate-Energy Tradeoff
AU - Clerckx, Bruno
N1 - Funding Information:
Manuscript received March 30, 2017; revised August 25, 2017; accepted November 8, 2017. Date of publication November 20, 2017; date of current version January 16, 2018. The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Amir Asif. This paper was presented in part at the ITG Workshop on Smart Antennas, Munich, Germany, March 2016 [1]. This work was supported in part by the EPSRC of U.K. under Grant EP/P003885/1.
Publisher Copyright:
© 1991-2012 IEEE.
PY - 2018/2/15
Y1 - 2018/2/15
N2 - The design of wireless information and power transfer (WIPT) has so far relied on an oversimplified and inaccurate linear model of the energy harvester. In this paper, we depart from this linear model and design WIPT considering the rectifier nonlinearity. We develop a tractable model of the rectifier nonlinearity that is flexible enough to cope with general multicarrier modulated input waveforms. Leveraging that model, we motivate and introduce a novel WIPT architecture relying on the superposition of multicarrier unmodulated and modulated waveforms at the transmitter. The superposed WIPT waveforms are optimized as a function of the channel state information so as to characterize the rate-energy region of the whole system. Analysis and numerical results illustrate the performance of the derived waveforms and WIPT architecture and highlight that nonlinearity radically changes the design of WIPT. We make key and refreshing observations. First, analysis (confirmed by circuit simulations) shows that modulated and unmodulated waveforms are not equally suitable for wireless power delivery, namely, modulation being beneficial in single-carrier transmissions but detrimental in multicarrier transmissions. Second, a multicarrier unmodulated waveform (superposed to a multicarrier modulated waveform) is useful to enlarge the rate-energy region of WIPT. Third, a combination of power splitting and time sharing is in general the best strategy. Fourth, a nonzero mean Gaussian input distribution outperforms the conventional capacity-Achieving zero-mean Gaussian input distribution in multicarrier transmissions. Fifth, the rectifier nonlinearity is beneficial to system performance and is essential to efficient WIPT design.
AB - The design of wireless information and power transfer (WIPT) has so far relied on an oversimplified and inaccurate linear model of the energy harvester. In this paper, we depart from this linear model and design WIPT considering the rectifier nonlinearity. We develop a tractable model of the rectifier nonlinearity that is flexible enough to cope with general multicarrier modulated input waveforms. Leveraging that model, we motivate and introduce a novel WIPT architecture relying on the superposition of multicarrier unmodulated and modulated waveforms at the transmitter. The superposed WIPT waveforms are optimized as a function of the channel state information so as to characterize the rate-energy region of the whole system. Analysis and numerical results illustrate the performance of the derived waveforms and WIPT architecture and highlight that nonlinearity radically changes the design of WIPT. We make key and refreshing observations. First, analysis (confirmed by circuit simulations) shows that modulated and unmodulated waveforms are not equally suitable for wireless power delivery, namely, modulation being beneficial in single-carrier transmissions but detrimental in multicarrier transmissions. Second, a multicarrier unmodulated waveform (superposed to a multicarrier modulated waveform) is useful to enlarge the rate-energy region of WIPT. Third, a combination of power splitting and time sharing is in general the best strategy. Fourth, a nonzero mean Gaussian input distribution outperforms the conventional capacity-Achieving zero-mean Gaussian input distribution in multicarrier transmissions. Fifth, the rectifier nonlinearity is beneficial to system performance and is essential to efficient WIPT design.
KW - Nonlinearity
KW - optimization
KW - waveform
KW - wireless information and power transfer
KW - wireless power
UR - http://www.scopus.com/inward/record.url?scp=85035769508&partnerID=8YFLogxK
U2 - 10.1109/TSP.2017.2775593
DO - 10.1109/TSP.2017.2775593
M3 - Article
AN - SCOPUS:85035769508
SN - 1053-587X
VL - 66
SP - 847
EP - 862
JO - IEEE Transactions on Signal Processing
JF - IEEE Transactions on Signal Processing
IS - 4
M1 - 8115220
ER -