Backscatter Communications: Inception of the Battery-Free Era—A Comprehensive Survey

Abstract

The ever increasing proliferation of wireless objects and consistent connectivity demands are creating significant challenges for battery-constrained wireless devices. The vision of massive IoT, involving billions of smart objects to be connected to the cellular network, needs to address the problem of uninterrupted power consumption while taking advantage of emerging high-frequency 5G communications. The problem of limited battery power motivates us to utilize radio frequency (RF) signals as the energy source for battery-free communications in next-generation wireless networks. Backscatter communication (BackCom) makes it possible to harvest energy from incident RF signals and reflect back parts of the same signals while modulating the data. Ambient BackCom (Amb-BackCom) is a type of BackCom that can harvest energy from nearby WiFi, TV, and cellular RF signals to modulate information. The objective of this article is to review BackCom as a solution to the limited battery life problem and enable future battery-free communications for combating the energy issues for devices in emerging wireless networks. We first highlight the energy constraint in existing wireless communications. We then investigate BackCom as a practical solution to the limited battery life problem. Subsequently, in order to take the advantages of omnipresent radio waves, we elaborate BackCom tag architecture and various types of BackCom. To understand encoding and data extraction, we demonstrate signal processing aspects that cover channel coding, interference, decoding, and signal detection schemes. Moreover, we also describe BackCom communication modes, modulation schemes, and multiple access techniques to accommodate maximum users with high throughput. Similarly, to mitigate the increased network energy, adequate data and power transfer schemes for BackCom are elaborated, in addition to reliability, security, and range extension. Finally, we highlight BackCom applications with existing research challenges and future directions for next-generation 5G wireless networks.

Wireless Power Transfer Techniques for Implantable Medical Devices: A Review

“…It is worth mentioning that radio frequency identification (RFID) demonstrated significant potential for low and high frequency WPT and energy harvesting applications. However, its implementation using different WPT techniques can be a major challenge for MIDs [220,221].…”

6G Enabled Smart Infrastructure for Sustainable Society: Opportunities, Challenges, and Research Roadmap

“…Ambient backscatter (AB) was proposed by [ 6 ] to enable tiny devices to operate without a battery, such that they are powered by redirecting ambient RF signals without requiring active RF transmission. Ambient backscatter communication is a form of backscatter communication that can harvest energy from devices in its “ambient” environment such as Wi-Fi, TV, and RF signal to modulate information [ 218 ]. When this passive backscatter system is integrated with an active transmission system, it forms the symbiotic radio (SR) [ 219 ].…”

“…There is also no need to allocate a different frequency spectrum for ambient backscattering communication systems (ABCS), thereby improving spectrum resource utilization [ 27 ]. When perfected, ambient backscatter communication will enhance the battery life of mobile devices [ 218 ].…”

Overview on 5G Radio Frequency Energy Harvesting

“…A backscatter communication architecture is suggested in [100], which combines ambient EH and reflection of this same energy modulated, with all its related signal processing aspects and multiple access techniques.…”