Backscatter radio communication for wireless powered communication networks

Backscatter radio communication has become a newly emerging technique for low-rate, low-power and large-scale wireless sensor networks. As this promising technology enables a long-range communication for sensors with low power in a distributed area, it is desirable to support wireless powered communication networks (WPCNs) that experience doubly near-far problem. In a backscatter radio based WPCN, users harvest energy from both the signal broadcast by the hybrid access point and the carrier signal transmitted by the carrier emitter in the downlink and transmit their own information in a passive way via the reflection of the carrier signal using frequency-shift keying modulation in the uplink. We characterize the energy-free condition and the signal-to-noise ratio (SNR) outage zone in a backscatter radio based WPCN. Numerical results demonstrate that the backscatter radio based WPCN achieves an increased long-range coverage and a diminished SNR outage zone compared to the active radio based WPCNs.