Modelling Battery-free Communications for the Cooja Simulator.

Recent progress on backscatter communications enable devices that, assisted by an unmodulated carrier, receive and transmit standard wireless protocols such as IEEE 802.15.4 with sub-milliwatt power consumption. This paradigm, that we call carrier-assisted communications, enables batteryfree devices due to its reduced power consumption. To develop at scale, and integrate seamlessly into networks of unmodified conventional nodes, we need novel protocols at the MAC layer and above that can coordinate the carrier generators with receivers and transmitters while maintaining energy and spectral efficiency. A highly effective tool to develop such protocols is a network simulator. We introduce models for the communication range, energy consumption and other characteristics of carrier-assisted links based on parameters gathered from real-world experiments. We implement the models in Cooja, a well-known simulator, creating the first carrier-assisted communications framework to simulate interoperable battery-free devices alongside conventional sensor nodes. We illustrate how such a tool can offer valuable insights in the development and evaluation of efficient protocols for carrier-assisted communications.