Protocol for over 300 metres and minimum of 20 kbytes datarate?

Question

We are trying to choose the most suitable connection protocol for wearable devices, with the following constraints:

1. 300 - 500 devices will simultaneously connect
2. About 1 km² site area—coverage is needed throughout the site.
3. Devices are moving
4. This is an industrial site, and so there will be concrete and steel obstructions
5. At least a 20 kilobyte datarate is necessary.

Update 7.12.2017

At the moment we are looking into:

1. Bluetooth mesh networking (Bluetooth 5, BLE)
2. LoRa
3. Nordic proprietary protocol

Has anyone worked with those protocols and in conditions stated above?

Answer 1

I would recommend some sort of mesh network, as obviously plain old WiFi or BT won't cover those distances. Zigbee is as good a candidate as any.

For hardware, AdaFruit does some good wearables, although if everyone has a smartphone, you might as well use those.

And, if you can figure out how to power it by battery, take a look at my answer to this question and the $20 Flutter :

Flutter is a high performance microcontroller platform for the connected age. Fast ARM CPU, hardware cryptography, battery charging, and onboard wireless with over 1 kilometer range. Easy to program with Arduino onboard.

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