Which protocol to use?

RE: Which protocol to use?

endnode — Thu, 07 Dec 2017 08:45:32 GMT

...you need to be damn sure what to do with the data to justify such investment (big industrial manufacturer investing in IoT should go there, others probably not).

RE: Which protocol to use?

endnode — Thu, 07 Dec 2017 08:44:18 GMT

I could imagine that with having hundreds of moving battery powered devices and roughly the same number of grid powered stationary observers connected to some high-speed network like WiFi or Ethernet. Taht will work pretty well even with BLE on such large area even if it is construction hall in car factory or similar thing (after some fine-tuning of course to cover all special shielded corners). But installation, maintenance and purchasing cost of such system will be significant (basically 5-10$ per moving beacon + 10-100$ per boarder observer, 10-100 of units replaced per year, 2-6 weeks of full time installation job of 2-10 people - basically engineers who understand deeply the radio and whole system - also replacing of batteries basically once a month to all moving units + probably 12 full-time guys to maintain the system and device fleet). Still it can be great but...

RE: Which protocol to use?

endnode — Thu, 07 Dec 2017 08:36:20 GMT

You cannot cover the area without heaving easy access to (ideally) multiple "boarder" exit points at the time. Yes, it can work as demo or in theory with large network of moving devices and just few exit nodes but our research (~2 years ago) showed that even the best in class (at that moment) commercial mash networks based on 2.4GHz radio cannot achieve any reasonable throughput in anything like real time (like dozens of seconds or minutes between event on the device and information reaching backend/boarder). And that was just ten devices in few rooms. I cannot imagine how that could reliably work with hundreds of devices on area of square kilometer. But maybe BT SIG mash or some other proprietary/open source project can deliver better performance today then what I've seen some time ago. And yes, battery operation definitely don't help, you can end up with battery life in weeks.

RE: Which protocol to use?

Pavel K — Wed, 06 Dec 2017 21:55:23 GMT

Thanks Jan, is that because of the battery? what if we were compromise, what do you think would be the best option in terms of range and stability?

RE: Which protocol to use?

endnode — Mon, 04 Dec 2017 11:05:24 GMT

Thanks for details and I guess we both see that these are pretty much incompatible with any low-power 2.4GHz radio solution;) You can try to solve it with BT SIG mash or other proprietary mash network with only few boa5rder routers but my guess is that it won't work reliably.

RE: Which protocol to use?

Pavel K — Mon, 04 Dec 2017 10:08:02 GMT

Jan, thank you for reply!

RE: Which protocol to use?

Pavel K — Mon, 04 Dec 2017 10:07:43 GMT

Hello Jan,

Thank you very much for your reply! I do apologise for not properly explaining all the details, let me provide information on your questions:

Devices are moving - its a wearable device for people
Its more towards fewer routers, if it is bluetooth on site go 1 km2, that will be a lot of nodes, very hard to maintain and install
All devices are battery powered, 190 mAh, we do need to be economical

I hope that gives clarity.

Regards Pavel

RE: Which protocol to use?

endnode — Sun, 03 Dec 2017 20:48:43 GMT

Ahoj Pavle,

My two cents: Just based on your high-level requirements pretty much any technology should be in principle able to transport this low throughput from hundreds of devices. BLE can do it (when you will install set of "hubs" which will be connecting to sensors and gather data one by one), the same with proprietary technologies like ESB and Gazzel, ANT is doing this in a gym or in a peloton so why not here, fancy things like BT SIG mesh or some proprietary mesh or even networks based on IEEE 802.15.4, all should do the job after certain work on the topology and application layer. So far so good.

However what you haven't set are other three main criteria which will break many candidates easily:

These hundreds of devices will be static or moving?
Should they build self-contained solution meaning just one or few border routers installed or you can afford network of static hubs covering comfortably whole site? I guess you understand that typical visibility on 2.4GHz low-power radio inside industrial indoors complex with lot of metal, water, thick walls, people and 2.4GHz "noise" (e.g. heavy Wifi/Zigbee/BT traffic) is 10-20m (and there will be corner cases where it can easily be less then 10m). So if you don't put any assumptions on devices and hubs you can easily end up in situation where none of these BLE-like technologies on nRF5x chips solve your problems.
What are power consumption criteria? Are there any devices powered permanently from the grid? Which devices are battery powered and how sensitive you are about batter exchange/recharging?

Cheers Jan