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

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

Petter Myhre — Mon, 18 Sep 2017 11:28:22 GMT

No problem :) Again, sorry for the delay. If there is nothing else, I would appreciate if you would accept my answer by clicking the grey circle next to it.

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

Al — Sun, 17 Sep 2017 06:58:01 GMT

Amazing. This is very useful info. I really appreciate your help Peter!

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

Petter Myhre — Sun, 10 Sep 2017 11:00:56 GMT

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.

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

Petter Myhre — Sun, 10 Sep 2017 11:00:54 GMT

Sorry for the late reply.

I did a test where I connect a peripheral and a central, with the minimum connection interval, 7.5 ms.

The central will read a characteristic value on the peripheral, and then disconnect. Nothing else.

I measured this to take around 25 ms, from the advertisement is sent out, till the last packet from the peripheral is sent to central.

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

Al — Thu, 07 Sep 2017 17:00:23 GMT

Hi Peter,

Do you plan on testing this? :)

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

Al — Sat, 02 Sep 2017 19:14:16 GMT

I'm currently exploring this option and hence not limited to predefined HW. Both Advertiser and scanner won't be stationary - it's actually people :)

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

Petter Myhre — Thu, 31 Aug 2017 11:34:41 GMT

I'm not sure. I'll have to test. Which SoftDevice are you using? Which chipset? Will there be a Nordic chip on both sides of the link? If not what will be the other device? Will the advertiser be stationary? And the scanner be passing by? Or vice versa?

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

Al — Wed, 30 Aug 2017 16:19:41 GMT

Hi Peter,

Thanks for your quick answer. 1 ms events are pretty rare. Most of the events will take between 40 and 100 ms. What is the minimum time required to advertise, connect and exchange data? Lets say its a serial number of a few digits. Data exchange is only in one direction.

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

Petter Myhre — Wed, 30 Aug 2017 14:33:09 GMT

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?