Energy efficient channel sensing for wake-up receivers.

ITU, the UN body that oversees development of information and communication technologies in its IMT 2020 recommendation identified three main heads of research for the development of communication systems for 5G and beyond. One these heads is « Massive Machine-Type Communications » which deals with developing low power technologies for communication in-between different machines. One of the main characteristic of these machine-type communications is that it is sparse, that is a message gets communicated rarely. As a result, it is inefficient in terms of energy to keep receivers permanently on. Instead, a standard practice is to duty-cycle the receivers, i.e., the receiver alternates between an ‘on’ and an ‘off’ state, and it is ensured that the receiver has a very low probability of missing the incoming signal. The detection algorithms however require the receiver to be on for the entire duration of the on-phase. We propose a new two-phase detection algorithm, which requires the receiver to quickly estimate whether there is an incoming signal at the beginning of the on-phase. If it detects an incoming transmission, it switches to a « cleaner » mode for the rest of the on-phase. Else, the receiver simply switches off for the rest of the on-phase and awakens only during the next on-phase. We show that this two-phase scheme has the same probability of false-alarm and missed detection as the basic receiver, and yet, on average, it consumes 50-60% less energy.