Fundamentals of Wireless Information and Power Transfer: From RF Energy Harvester Models to Signal and System Designs

Collaborative RF and Lightwave Power Transfer for Next-Generation Wireless Networks

“…Deploying RF WPT systems introduces several new concerns for human health due to RF radiation. In RF WPT systems, the sensitivity of an EH receiver, i.e., −10 dBm, is much higher than that of a conventional information decoding (ID) receiver, i.e., −60 dBm (see [2] and references therein). To enable RF WPT, manufacturers and network operators need to increase the transmit power levels to achieve a reasonable EH performance at the receiver side.…”

“…Similarly, the rate-energy region of RF can be obtained based on modifying the RF signal portions used for ID and EH. In this context, the RF data rate and RF EH metrics are computed according to the conventional rate formula and the nonlinear EH model [2] (i.e. P Sat = 24 mW, a = 150, b = 0.014; with the same notations as in [2]), respectively.…”

“…To cope with this issue, simultaneous wireless information and power transfer (SWIPT) technology has been proposed, which enables wireless devices to be continuously recharged via electromagnetic waves [2], [3], and opens new possibilities for the sustainability of future networks. SWIPT based on transmitted radio frequency (RF) waves is an interesting solution; however, due to the inevitable spectrum crunch, solely relying on RF may not be possible due to the need to jointly meet the expectations of (i) 10-fold longer device battery lifetimes [4], and (ii) the global mobile data traffic in excess of 100 exabytes [5], while respecting the transmit power constraints imposed due to various safety concerns [6].…”

Optimal energy beamforming under per‐antenna power constraint

“…Let us express the positive semidefinite matrix Q by its eigenvalue decomposition as 1 and v 1 are the largest eigenvalue of H H H and its corresponding eigenvector, respectively. We can rewrite the set of constraints q i,i ≤ p i as e T i Qe i ≤ p i , since q i,i = e T i Qe i , where e i = [0 · · · 1· · · 0] T with 1 as its ith element and 0 elsewhere.…”

“…Recent advances in microwave wireless power transfer (WPT) technology enables us to build wireless powered communication networks (WPCNs), where wireless devices such as internet‐of‐things devices, RF identification tags, wearable electronic devices, smartphones, etc, are powered over the air by wireless power transmitters. In WPCNs, the wireless devices harvest the energy from received signal.…”