LR-TSCH: Network Time Synchronization for Dummies!

One of the most important things to master, in order to become successful in today’s society, is Time Management. Operating ultra-low power wireless mesh networks are not different – arriving perfectly on time, getting the job done efficiently and effectively, and then moving on to the next task (or taking a rest) is what’s required in order to excel. LumenRadio are best-in-class in this discipline – let us explain what’s in it for you.

What is it?  

When you are operating mesh networks, while also duty-cycling the radios to conserve power, synchronizing the clocks of all devices becomes ridiculously important. Duty-cycling basically means turning the radio on and listening at defined intervals, and then back off again to save power and/or do other things. And if you then wake up at the wrong time, you will hear nothing but silence.

Within MiraMesh, we have implemented a technology we call LR-TSCH to handle above – as in LumenRadio’s performance-tuned version of Time-Synchronized Channel-Hopping. What makes this technology different is that it is:

  • Lean, as in that it uses all available sources (i.e. timestamps) for synchronization. It does not rely on a specific type of message/beacon being sent in the network – if something is transmitted by a device, we see it as relevant input for clock synchronization.
  • Adaptive, as it learns the clock-drift for each individual device and starts to compensate for it. And as drift also varies with the ambient temperature – location (indoor/outdoor), time-of-day or season does not affect the accuracy we can achieve.
  • Automatic, since you as a user do not have to worry about this – MiraMesh takes care of this in the background.
What does it do?
  • Simple, it keeps the clocks of all devices in a network accurately synchronized. And when we say accurately, we mean REALLY accurately – 5 us maximum clock-drift between neighboring devices and maximum 50 us across a whole network.
Why is this important for you? 
  • This allows you to build wireless meshing networks of battery-operated devices, thanks to the power savings enabled. Zero wires allow you to create new and completely unique user experiences from an installation and commissioning perspective, while also making retrofit a much more compelling offer.
  • You can also timestamp your data, knowing that observations from the same point-in-system-time actually happened at the same point-in-real-time. This will allow you and your customers to refine your analysis, rather than realize you’ve been chasing ghosts in your dataset due to clock drift.
  • It also goes the other way around, giving you the possibility to schedule events with an extreme accuracy to happen simultaneously or in a deterministic sequence across your network.
  • All-in-all, it helps you to maximize your efficiency in the time dimension. To use an analogy, it’s like perfectly timing catching your bus to work – it allows you to snooze one more time before getting up and you don’t waste any time waiting at the stop.
What does it mean for LumenRadio?  
  • Since ultra-low power consumption is one of our trademarks, not wasting time and energy by “waking up too early or staying up too late” becomes key – being able to duty cycle the radio extremely hard, is what enables us to build meshing networks of battery-operated devices with 10+ years battery-time.
  • And keeping the devices on a very tight leash in the time dimension, also enables us to offer one of our other killer features – providing a concurrent Bluetooth connection (or any other third-party radio protocol) by time-sharing the radio between multiple communication stacks. (Check back for an explanation of this feature in a couple of weeks.) This requires perfect timing to succeed, which leaves no room for clock-drift among your devices.

 

Don’t miss the first part in our  “for Dummies” blog trilogy covering our Cognitive Coexistence technology for interference mitigation here.