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Towards Wide-area Backscatter Networks

Backscatter communication --- reflecting or absorbing ambient wireless signals --- enables transmissions at several orders of magnitude lower energy cost when compared to conventional low-power radios. The past few years have seen signficiant progress with systems demonstrating the ability to synthesise transmissions that are compatible with WiFi, ZigBee or BLE at μWs of power consumption. However, these systems achieve a maximum communication range of tens of meters which severely limits the possible applications. On the other hand, our recent system LoRea demonstrates that backscatter communication can achieve a significantly longer range reaching up to a few kms when the tag is co-located with the carrier source. In our vision, such a large range could be a key enabler to develop wide-area networks of battery-free sensors. In this paper, we build on our system LoRea and identify issues of improving the reliability of weak backscatter links, increasing the range and supporting the operation of multiple tags as the key challenge to our vision, and present our preliminary efforts to address them.