What is the maximum number of UWB beacons that can be used in a given environment ?
UWB beacons would require BLE connection for the UWB ranging to be carried out. However, there is an upper limit on the number of bonded BLE devices that can be saved on iPhones or Android. I believe this number is around 100. So, how does UWB beacon overcome this limitation if I want to have these installed across multiple floors in a large building ?
there is really no upper limit of UWB beacons; you can easily have hundreds or even thousands of them around. Of course if you put all of them really close to each other there will be collisions in the radio spectrum for both BLE and UWB, but we don’t think it is practical to do that.
Here is a typical scenario:
- UWB beacon advertises its presence over BLE
- A phone picks up the signal and hand-shake over BLE
- Once the connection is established (let’s say 1-2s later) both beacon and phone turn on UWB
- Both devices start ranging over UWB and produce distance measurement
- Now the best would be to simply close the BLE connection and close the UWB ranging; You got the measurement and unless you moved significantly there is not need to get another ranging session
All of above should take less than 2-3 seconds.
Phone can establish BLE connections to many beacons around at the same time.
Good practice would be to make sure you close these connections, so that the phone is not overwhelmed.
Thank you for your response. I have a couple of questions that I am not clear about.
- You still need to establish a BLE connection, right ? Does Estimote beacons only connect or do you have to pair each of them as well ?
- My understanding is that if you do not pair, then your BLE communication is not secure. Isn’t that a security concern on the Estimote beacons ?
- Can we carry out the BLE traffic via BLE beacons (iBeacon for example) instead of actually having a connection established ?
Adding to my previous questions.
If you do not pair and only connect, then does it mean you have to manually intervene to establish the connection or can it be done in the background as you approach different beacons placed in different areas of the building ?
the estimote SDK does all this connection related activity under the covers… but the beacons are not paired.
if u get the sample IOS app from apple you will see the complete flow…
normal BLE scan for known UUIDs
normal BLE connect
then normal BLE write to establish the UWB data session,
then normal BLE notify of the positioning data from the UWB device
then the apple notify will call back at other entrypoints with the positioning info.
initially only distance, later with the vector ranging info.
the estimote SDK hides all that and provides
and the ranging callback with estimote data and passthru vector info from the IOS ranging callback
you can provide some optional control on the BLE Connect… (do it automatically, or have some app control when to actually do ranging… )
I do both in our IOS app depending on the circumstances