Janus general discussion forum

Janus general discussion forum

Wake-up tones - make them optional?

posts: 46
Dale Green (our FH and JANUS physical layer guru) has recommended that the wake-up tones at the beginning of the JANUS signal should be made optional. The advantages of this approach are that it saves power and a lot of time-bandwidth product when nodes are in conversation, driving down costs and overhead.

With the wake-up tones made optional, a node looking to make contact can still preface the main JANUS signal with wake-up tones to increase the chances of stimulating other nodes that may be asleep. Alert nodes can run their detectors on the 32-chip preamble and sleeping nodes can choose either to do that (with options to wake up only for the next message, or perhaps store enough raw data to detect and decode afterwards) or listen for the wake-up tones, as they wish.

One implication of this is that general detectors and decoders must be independent of the wake-up tones, using the 32-chip sequence to detect, synchronise and estimate Doppler, etc., as meets their needs. The example implementations to be released with ver 1.0 will satisfy these requirements.