I have a question about Long Range communication of nRF52840.

[schosdas]

Hello,

I'm going to send data from a distance of 100-150m using Bluetooth long range communication.

When I looked up some examples of this, I saw that two development boards were used as central and peripheral, respectively.

I have a few questions about this.

1. Can I test this long range with one nrf52840 board and nRF connect app?  I'm planning to buy more nrf52840 later, but I only have one now. Would this be possible?

2. I will not use a special antenna because my goal is to develop a small device.  In this case, is it possible to communicate at a distance of about 150 meters in an obstructed building?

And is the communication slow?  (Continues to transmit sensor data to central from peripheral)

3. Which example would you recommend starting with for this test? (SDK v17)

Thank you!

[Simonr]

Hi

1. This depends on what phone you're using the nRFConnect app with, as quite a few phones still don't support Coded PHY advertising/scanning. We have a GitHub issue on this here, with a list of Coded PHY tested phones. Additionally to the ones listed there, most flagship models from 2019 and onwards support Coded PHY as well.

2. That depends heavily on the environment in this building I think. Is it an office space or similar that has a lot of other radio activity at the 2.4GHz band, and what exactly do you mean by an obstructed builiding? If there are multiple concrete walls between the two it's safe to say that they won't be able to communicate. I think the number of obstructions and the interference from other devices should be rather limited to achieve this. I would get a second DK and test this in the building you're planning on setting this up in if I were you.

The communication is 8 times slower than "regular" 1MBPS BLE transmissions, because of the way the Coded PHY works, where it essentially sends every message 8 times on different channels to make sure the message is received and put together in the receiving end. 

3. There are no example projects that use Coded PHY by default in the nRF5 SDK v17.0.2 I'm afraid, but modifying an example like the ble_app_uart project should be simple enough. In fact, we've done so as a demo before for SDK v15.2, which I can upload here if you'd like. We also have the heart rate monitor application (central and peripheral) in the nRFConnect SDK modified to use the Coded PHY.

Best regards,

Simon