Multiple networks to cover large amount of tags?

Dear all,
to recognize several active tags with a high positioning rate of 10Hz in ONE AREA (and keeping in mind the limit of 150Hz clock) afaik I’m limited to 15 tags to be recognized by the 4 same anchors - correct?
To work around this limitation please let me know if this would work:

… what about using 4 additional anchors (mounted next to the ones already installed) but with a different PANID.
15 tags (give them even numbers, 2,4,6,…30) are configured for PANID #1
15 tags (give them odd numbers 1,3,5,…29) are configured for PANID #2
so I’d have 30 tags split into 2 PANIDs.

As I’ll be using active tags and localization gets received on the tag side I’m fine with different PANID’s - it actually doesn’t matter if a tag belongs to PANID #1 or #2 as long as the position is correct…

And how far does this go, let’s say by installing 4 networks with different PANID’s in one place, dividing tags into 4 groups (each group has 15 tags) - will I be able to track 60 tags in one place like that?

Thanks!

Hi Jens,

that would be a perfect scalable network :wink: but unfortunately is not the case of PANS and shared media network I believe. 150 Hz is really the physical limit which PANS can achieve.

When two networks with two different PANIDs overlaps, all nodes (Anchor/Tag/Bridge) in the overlapped area will share the air-time (they will be synchronous). The system should work in a such scenario, but due to sharing the air-time, you need to ensure the deployment rules should be applied for the combined network. E.g. the maximum amount of Anchors which can be in-range with each other is 30. As well as the limit of 150 Hz total location for the Tags is for the combined networks.

Nodes from each network will exchange measurements and data only with the nodes from its network. The air-time can be reused (either for the Anchors/Bridge or Tags) in any area if no limit of nodes have been exceeded. I.e. it’s possible to have a network of more than 30 anchors spread over the installation, or there can be another 15 Tags @ 10 Hz if they are not in range with other 15 active Tags running at 10 Hz (or Anchors which communicates with those Tags).

Cheers,
TDK

Hi TDK,

thanks!
So there is actually no way to work with TWO sets of 15 active tags within the same area unless update / refresh rate drops to a lower rate of maybe 5 Hz or 1 Hz for 150 tags?

But one thing makes me think - as you mention that nodes from each network will exchange measurements and data only with the nodes from its own network - how would two networks side by side work then?

The tags might ‘see’ each other due to the distance but are actually assigned to either one or the other network - will they still share the same air-time (even though they not communicating with the other anchors) or to put it into other words: to make this work, are there real physical boundaries needed to make sure that tags are wirelessly isolated from seeing the other group?

Thanks,
Jens

Hi Jens,

yes, you understand it correctly. There must be real physical boundaries so the Tags would not influence each other to achieve the 2 networks as listed above. PANS uses TDMA scheme and all nodes have implemented collision detection, avoidance and resolution mechanism. The TDMA has fixed slot scheme where some slots are assigned for the Anchors and some for the Tags. Each node can compete and reserve proper slot(s) for itself. The slot(s) assignment depends on if the slot if free in that area. Networks with different PANIDs will not exchange data, but they share the same air-time / TDMA slots - that’s the physical fact.

Considering the network pictures you sent in the previous post, then if the Network ID #1 fully overlaps the Network ID #2 then all Anchors will get some seat and all can join its network cluster. But some part of the Tags (either from both networks or from one of them) will not get free data slots. It will have to wait until some slot frees up. Please see also the documentation for more details:
https://www.decawave.com/dwm1001/systemoverview/

Cheers,
TDK

Hi, All!

I’ve got similar question.

There are all UWB devices in one PAN network. There are two areas (e.g. buildings). There are 15 tags @ 10Hz in one area and 15 tags @ 10Hz in another area. Tags from one area aren’t in-range with tags in another area.

So the questions are:

  1. Will it work without collapses?
  2. Will we get all 30 tags coordinates at 10Hz frequency?
  3. We should use at least 1 anchor initiator for each area, shouldn’t we?
  4. Can we have 2 host listeners for every area? So we would connect to different listeners IPs and get information from UWB devices for every area. And every area is under one host.

Hi @what_is_love_chik
If the network from Building 1 is not in range with the network from Building 2 then the answers are

  1. yes it will work without collapses
  2. yes
  3. You must use one Anchor initiator per area as they are separated.
  4. Actually Im not getting the point here but you can have as many listeners as you want but you must point them to the single proxy that will take care about the message duplicity.

Cheers
JK

Thank you for answers!