Hop count routing: a routing algorithm for resource constrained, identity-free medical nanonetworks

Nanodevices, tiny robots operating within a human body, may help to detect and treat many kinds of diseases. As their individual abilities are limited by size, they need to work in concert. Communication provides the fundamental ability to enable this collaboration. In medicine, nanodevices act as a tool for a physician to report sensor data and receive action commands. Their communication thus flows to and from a gateway to the macro-world. Routing algorithms focus on enabling these data streams.We propose a new routing algorithm for medical nanonetworks based on a network topology constructed from the hop count distance to a single gateway. It exploits the distance as a direction indicator to deliver data towards or away from the gateway. The resource constrained nanodevices store no unique identity, but only require a single integer each. Simulation results show that a naive implementation produces an exponential number of messages. We mitigate this with a second approach by removing the hop count when retrieving sensor data, which requires only a linear number of messages. Our comparison finds the latter to be more efficient in terms of transmitted messages, while the first implementation is more suitable for routing several messages in parallel.