Ambient Backscatter Assisted Wireless Powered Communications

Abstract

Ambient backscatter communication technology has been introduced recently, and is then quickly becoming a promising choice for self-sustainable communication systems as an external power supply or a dedicated carrier emitter is not required. By leveraging existing RF signal resources, ambient backscatter technology can support sustainable and independent communications and consequently open up a whole new set of applications that facilitate Internetof-Things (IoT). In this article, we study an integration of ambient backscatter with wireless powered communication networks (WPCNs). We first present an overview of backscatter communication systems with an emphasis on the emerging ambient backscatter technology. Then we propose a novel hybrid transmitter design by combining the advantages of both ambient backscatter and wireless powered communications. Furthermore, in the cognitive radio environment, we introduce a multiple access scheme to coordinate the hybrid data transmissions. The performance evaluation shows that the hybrid transmitter outperforms traditional designs. In addition, we discuss some open issues related to the ambient backscatter networking. Index TermsAmbient backscatter communications, modulated backscatter, RF energy harvesting, self-sustainable communications, wireless powered communications, Internet-of-Things. I. INTRODUCTIONInformation transmission based on modulated backscatter of incident signals from external RF sources has emerged as a promising solution for low-power wireless communications. The power consumption of a typical backscatter transmitter is less than 1 µW [1], which renders excessively long lifetime, e.g., 10 years, for an on-chip battery. This low power consumption well matches the harvestable wireless energy from RF sources, e.g., typically from 1 µW to tens of µW [2], [3]. This additionally renders RF energy harvesting to be an alternative to power backscatter transmitters. Furthermore, backscatter communications Dong In Kim is the corresponding author 2 can be embedded into small gadgets and objects, e.g., a radio frequency identification (RFID) and passive sensor. Therefore, backscatter communications is also envisioned as the last hop in the Internet-of-Things (IoT) [4], which requires low cost and ubiquitous deployment of small-sized devices [5].Due to recent dramatic increases in application demands, the requirement for backscatter communications has gone beyond the conventional RFID towards a more data-intensive way. This strongly raises the need for re-engineering backscatter transmitters for better reliability, higher data rates, and longer interrogation/transmission range. However, traditional backscatter communication techniques, e.g., RFID, are hindered by three major shortcomings: 1) The activation of backscatter transmitters relies on an external power supply such as an active interrogator (also called a reader or carrier emitter) which is costly and bulky.2) A backscatter transmitter passively responds only when inquired by a reader. The communication link ...

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