is BLE SPP full duplex?

Question

I'm working on a project that requires BLE Serial Profile.

I have successfully implemented it, but now I'm wondering what happens when server is sending data to the client, and client wants to send data back (while server is still sending). Is this handled on the low level with a queue or something similar?

Is there any risk that messages will get lost?

Thanks for any help.

Answer 1

Bluetooth provides the effect of full duplex transmission through the use of time division duplex (TDD). In principle transmission and reception do not happen at the same time. So in your case there is no risk of collision (loss) of data packets.

As you can see "Central" and "Peripheral" have a window of 625us during which they transmit.

For further details you can read "Timeslot" chapter of the base band specification in Core Bluetooth specification. https://www.bluetooth.com/specifications/specs/core-specification-5-3/