Whats the minimal time required to advertise, connect and transfer the smallest packet using BLE Beacons?

[Al]

Thanks for your help עוטד. I want to use BLE / beacon technology in order to track items that pass-by in high-speed and close proximity (0.5m). This means I only have a few ms (1-100) in order to track the device. It is a set of devices that are already paired. Can BLE support such use case?

[Petter Myhre]

The minimum advertising interval is 20 ms, so if the devices are only in range for 1 ms, then it is a a very big chance that the advertisement is missed by the scanner.

Then you have to connect, and exchange the data.

Is 1 ms a hard limit?

[Petter Myhre]

I think this is the minimum time, or close to it. Bear in mind that this does not take into account the time it takes for the scanner to actually catch an advertisement, this depends on the advertising interval, scan window/interval, interference and so on. It also assumes that the central knows which peripheral to connect to, so it doesn't have to receive an advertisement, look for a specific UUID or similar in the advertisement, and then connect. It also assumes that the central knows the attribute handle of the characteristic value it wants to read, as it doesn't do any service discovery and so on.