Transfer Speeds at 100m with 15 devices

[mredp]

Hey,

I am having trouble validating this idea through research. I was hoping someone could give me some ballpark feedback.

The setup:

- 15 NRF52832 devices on custom PCB (30mmx50mm)

- All around 100m away outside with little to no obstacles in the way

- I need to stream data from each device. This means that the Bluetooth transfer speed needs to be faster than the combined data collection speed.

- Each device collects at 24kbps. So there is a combined 360kbps of data. 

I imagine that I need to connect to each device individually and receive data. Then cycle through to the next device. 

The connection parameters would be:

- BLE 5.0

- PHY: 2M

- TX power: 4dB

- connection interval 7.5ms

- data packet length extension on

- connection event length extension on

I can calculate theoretical transfer speeds using the nordic online power profiler. However, it's hard to get data at long distances. Also, I am not sure if I can cycle through the 15 devices fast enough?

Can I achieve this transfer rate (360kbps) at 100m? If not, what distance should be OK?

[Dmitry]

I mean an implementation that uses radio directly. In this case, you have no overhead of LL/L2CAP/ATT layers and acknowledgements, and you have full control over timings, thus avoiding collisions. Of course, this is more complex challenge than using BLE.

mredp said:

To confirm, you think a simple custom protocol could communicate with 15 devices 70 Metres away sampling at 360kbps (total)?

I cannot confirm this (there are too many factors), you have to do some expreriments. What I can say exactly - Coded PHY will give you a longer distance, and in your case Coded PHY is possible only with custom protocol.