An LTE-Harvesting BLE-to-WiFi Backscattering Chip for Single-Device RFID-Like Interrogation.

Recent work in backscatter modulation has enabled very low-power communication between an loT tag and commodity hardware such as WiFi or BLE transceivers [1]–[4], enabling a new set of exciting loT applications such as on-body sensors or asset trackers that demand low power and low deployment cost via compatibility with existing standards. However, such backscatter approaches tend to require two external devices: a transmitting tone generator [3], [5] or access point (AP) [1], [2], [4] and a receiving AP [1]–[5] in order to perform tone-to-WiFi [3], [5], WiFi-to-WiFi [1], [2], [4] or BLE-to-BLE [4] communication without requiring power-expensive RF signal generation on the backscattering loT tag (Fig. 21.5.1, top). Unfortunately, not all applications natively have multiple available APs, and deployment of additional infrastructure can be expensive. Since there are few, if any, commodity devices that feature full-duplex communication or multiple radios operating concurrently with the same standard in the same band, a low-power backscatter IC that can be interrogated by a single device has not been demonstrated. In addition, most such backscattering loT tags require either batteries or auxiliary energy harvesters, which can further increase deployment and/or maintenance costs.