  Wireless sensor networks are deployed in many monitoring applications but
still suffer from short lifetimes originating from limited energy sources and
storages. Due to their low-power consumption and their on-demand communication
ability, wake-up receivers represent an energy efficient and simple enhancement
to wireless sensor nodes and wireless sensor network protocols. In this
context, wake-up receivers have the ability to increase the network lifetime.
In this article, we present T-ROME, a simple and energy efficient cross-layer
routing protocol for wireless sensor nodes containing wake-up receivers. The
protocol makes use of the different transmission ranges of wake-up and main
radios in order to save energy by skipping nodes during data transfer. With
respect to energy consumption and latency, T-ROME outperforms existing
protocols in many scenarios. Here, we describe and analyze the cross layer
multi-hop protocol by means of a Markov chain model that we verify using a
laboratory test setup.
