Radio-triggered Wake-ups with Addressing Capabilities for Extremely Low Power Sensor Network Applications

Sensor network applications are generally characterized by long idle durations and intermittent communication patterns. The traffic loads are typically so low that overall idle duration energy consumption dominates. Low duty cycle MAC protocols are used in order to reduce the energy consumption in idle periods. However, lowering the duty cycle value in favour of energy consumption results in increased latency, which makes this approach undesirable for many practical applications. In this paper, we propose Radio Triggered Wake-up with Addressing Capabilities (RTWAC) that allows suppressing the idle duration current consumption. Our solution consists of an external low-cost hardware wake-up circuit attached to the microcontroller of a sensor node. In order to communicate with a sensor node, a special kind of out-ofband modulated wake-up signal is transmitted. The modulated signal contains data that enables to distinguish between differently addressed nodes in order to avoid undesired node wake-ups. Furthermore, we advocate the idea of combining RTWAC to a MAC protocol running on the normal sensor node radio in order to simultaneously achieve low energy consumption and low latency for reliable data communication.