A Software-Defined Radio System for Backscatter Sensor Networks

Backscatter radio is proposed for sensor networks. In that way, the transmitter for each sensor is simplified to a transistor connected to an antenna and therefore, the cost for each sensor´s communicator becomes negligible, while energy used for wireless communication per sensor is minimized. A software-defined transceiver is built to transmit a carrier, receive the reflections from various sensors and extract their transmitted messages. This work presents a thorough model of the backscatter radio link, the system architecture and a set of data extraction techniques for each sensor´s information, testing in practice a sensor communicating through backscatter at a range of approximately 15 meters indoors, with 5 milliwatt transmission power at 10 bits per second. This work highlights the idiosyncrasies of the backscatter channel and provides a new communication perspective in the fertile area of scalable sensor networks, especially when low bit-rate, ultra-low cost sensors are required.