Simultaneous Wireless Information and Power Transfer Under Different CSI Acquisition Schemes

Abstract

Abstract-In this work, we consider a multiple-input singleoutput system in which an access point (AP) performs a simultaneous wireless information and power transfer (SWIPT) to serve a user terminal (UT) that is not equipped with external power supply. In order to assess the efficacy of the SWIPT, we target a practically relevant scenario characterized by imperfect channel state information (CSI) at the transmitter, the presence of penalties associated to the CSI acquisition procedures, and nonzero power consumption for the operations performed by the UT, such as CSI estimation, uplink signaling and data decoding. We analyze three different cases for the CSI knowledge at the AP: no CSI, and imperfect CSI in case of time-division duplexing and frequency-division duplexing communications. Closed-form representations of the ergodic downlink rate and both the energy shortage and data outage probability are derived for the three cases. Additionally, analytic expressions for the ergodically optimal duration of power transfer and channel estimation/feedback phases are provided. Our numerical findings verify the correctness of our derivations, and also show the importance and benefits of CSI knowledge at the AP in SWIPT systems, albeit imperfect and acquired at the expense of the time available for the information transfer.Index Terms-Simultaneous wireless information and power transfer (SWIPT), energy harvesting, wireless power transfer, TDD, FDD, analog feedback.

Wireless Powered Relaying Networks Under Imperfect Channel State Information: System Performance and Optimal Policy for Instantaneous Rate

“…In terms of perfect and imperfect channel state information (CSI) addressed in [9][10][11][12][13]. In particular, a multipleinput single-output (MISO) system was studied [9] while the authors in [10] considered a transmit power allocation issue for a hybrid EH single relay network with channel and energy state uncertainties with the aim to optimizing system throughput over a limited number of transmission intervals, in which sub-optimal online, optimal online and optimal offline allocation schemes were put forward.…”

“…In particular, a multipleinput single-output (MISO) system was studied [9] while the authors in [10] considered a transmit power allocation issue for a hybrid EH single relay network with channel and energy state uncertainties with the aim to optimizing system throughput over a limited number of transmission intervals, in which sub-optimal online, optimal online and optimal offline allocation schemes were put forward. In [11], two-way fullduplex (TWFD) relaying with a residual loop interference (LI) was studied, where data is exchanged between users by the assistance of a FD relay.…”

Exploiting hybrid time switching-based and power splitting-based relaying protocol in wireless powered communication networks with outdated channel state information

“…In addition, thanks to recent advancements of circuit, it is noted that WPCN is feasible, since extending coverage range of relaying wireless networks and then combining them with RF-based energy harvesting become key factors of next generation wireless systems [3][4][5][6][7][8][9]. In [3,4], the authors put forward an energy pattern aided simultaneous wireless information and power transfer (SWIPT) system and the optimal design for SWIPT in downlink multi-user of orthogonal frequency division multiplexing systems, in which such systems utilize signals received from a fixed access point (AP) to perform two duties, harvesting energy and decoding information.…”

“…Meanwhile, it is proved that communication security and the efficiency of wireless energy transfer can be provided effectively in a joint cooperative beam forming and energy signal scheme in [5]. To evaluate the performance of wireless powered system, there were various investigations conducted into the trade-off between the functions of information transfer and wireless power transfer [6][7][8][9]. In particular, the work in [9] focused on SWIPT in multi-relay scheme of two-hop relay systems, in which by utilizing the concept of distributed space-time coding by multiple relay nodes at the same time, the transmission was positively assisted from source to destination.…”

“…To evaluate the performance of wireless powered system, there were various investigations conducted into the trade-off between the functions of information transfer and wireless power transfer [6][7][8][9]. In particular, the work in [9] focused on SWIPT in multi-relay scheme of two-hop relay systems, in which by utilizing the concept of distributed space-time coding by multiple relay nodes at the same time, the transmission was positively assisted from source to destination. Furthermore, a multiple-input single-output system was considered, in which an AP functions as a SWIPT for a user terminal which was not provided with any external power supplies [10].…”