2 Mbps BLE or 2 Mbps Nordic proprietary mode

[Vlad Mokhnachov]

Hi!

We have working solution with custom rf protocol based on NRF52832 and NRF52840(now it use 2 Mbps Nordic proprietary mode). Now we want improve it.

Could You give some advice about rf mode selection?

As I see 2Mbps BLE mode has better rx sensivity and Co-Channel interference characteristic. But it requires 2 bytes in preamble.

We are using many devices in one room with different rf channels so crosstalk is very important things for us. Will it better use 2Mbps BLE mode?

[Andreas]

Hi,

 

In theory you should see somewhat better performance with the 2Mbps BLE mode, but you will have to test it in your specific use case. If building your system from the bottom, not requiring backwards compatibility with the 2Mbps NRF mode you might as well just use the 2 Mbps BLE mode.

 

Best regards,

Andreas

[niebert]

2 byte preamble may not be necessary, this is ambiguous. BLE standard requires two bytes, but the "BLE mode" may be compatible with 1 byte preamble.

Concerning crosstalk, what exactly is it you want to avoid by this choice? What you want to do is to use different access addresses for different channels to avoid collisions.

[Vlad Mokhnachov]

Address dependent from channel, so device will not receive packet from another pair.

In our cases some different pairs(Master + Slave) can be placed close one to another. They will make noise for each other if they have close channels. From current experiments they should have channels N and N + 6 for stable link(no failed packets).

So we have 88 / 6 = 14 not overlapped channels. And some of them will be poor because of WIFI.

It will be perfect increase this number.