Chirp Based Backscatter Modulation

The Internet of Things (IoT) envisions ubiquitous, cheap and low data rate connectivity between humans, machines and objects. The main technology that can satisfy this vision is wireless communication technology, but to embed this into objects at a large scale, some requirements like battery-free and long range communication should be considered. In this work we propose a modulator that can backscatter different chirps, based on Chirp Spread Spectrum (CSS) modulation which can achieve high sensitivities, meaning long range communication. Moreover, we prove with this design that we can reflect backscatter Long Range (LoRa) preamble symbols with a Spreading Factor (SF) of 7 and 125 kHz of bandwidth. Thus, it will be possible to reuse the LoRa receivers already developed.