Performance analysis of simultaneous wireless information and power transfer in MISO systems

Abstract

A scenario in which a multi-antenna access point (AP) transfers both information and power to a single-antenna user terminal (UT) is considered. The UT harvests energy from the received signals to perform operations such as channel estimation, uplink signaling, and data decoding. Differently from most state-of-the-art works on this subject, a non-zero power consumption for data decoding at the UT is considered. Three cases of practical interest are studied: 1) time-division duplex (TDD) communications, and imperfect channel state information (CSI) at the AP, 2) frequency-division duplex (FDD) communications, and imperfect CSI at the AP, 3) no explicit duplexing scheme and absence of CSI at the AP. Closed-form representations of the ergodic downlink rate, and analytic approximations of the optimal durations of power transfer and channel estimation/feedback phases are derived for the three cases. Numerical findings confirm the accuracy of the analytic results. The presence of CSI at the AP for both considered duplexing schemes, albeit imperfect and resource-demanding, brings significant performance enhancements in simultaneous wireless information and power transfer (SWIPT) systems. Furthermore, the TDD scheme consistently outperforms FDD scheme over practical signal-to-noise ratio (SNR) range, confirming the potential of this duplexing scheme for future energy efficient networks.

Outage performance on threshold AF and DF relaying schemes in simultaneous wireless information and power transfer systems

“…In [8], the authors proposed a robust beamforming design for the multi-antenna SWIPT systems to maximize the worst-case harvested energy for the energy-harvesting receiver (ER), as well as to guarantee that the rate at the IR is above a threshold. In a MIMO SWIPT system, the authors of [9] derived closed-form expressions for the energy shortage and data outage probability under the three cases for the CSI knowledge at the transmitter: no CSI, and imperfect CSI in case of time-division duplexing and frequency-division duplexing communications. In a power splitting (PS)-based multiple-input single-output (MISO) interference channel for SWIPT, the total transmission power was minimized by joint beamforming and PS under both the SINR and EH constraints in the presence of local CSI [10].…”