Anchor initiator

Wireless Connectivity Ultra-Wideband
1

Folks:

Can anyone explain an anchor initialization procedure ?

  1. How does it communicate with other anchors ?
  2. Supose that there are 4 anchors separated by 30 m in a square. How does it work ?
  3. Now supose that there is a 5th anchor which is not in range of initiator but is in range of one of the 4 anchors. How it receives synchronization ?
  4. Also what is the purpose of an anchor initiator?
    What is the documentation that explains in detail about this subject ?

Regards

Andre

2

Hi Andre,

  1. In short, if there is no existing network, the Initiator will start a new one. Then one by one the other Anchors will join. If there is already an existing network, the Initiator will join and become a normal Anchor.
  2. The Anchors will daisy chain, so they would be synchronized and each will occupy a non-colliding air-time.
  3. It will receive and being connected via any already connected Anchor (just one is enough).
  4. See 1 and also https://www.decawave.com/dwm1001/systemoverview/

Cheers,
TDK

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3

Thanks TDK, your explanation is great.

Some clarifications I think might be helpful:

  1. A network is defined by a “PANID”. All nodes (initiators, anchors, tags and observers) with the same PANID will be part of the same network. As TDK mentioned, a network is started by an initiator and other nodes can join the network. Having multiple networks (with a different PANID) is also supported but the initiator of the first network will be used to ensure the TDMA scheme. Different AES keys can be set up to keep information private between the networks.

  2. A more correct term for the “daisy chain” is TDMA (Time-Division Multiple Access). This means each node has a specific time slot available to do it’s UWB communication. This could be sensor data and/or location uplink, TWR (To Way Ranging) between anchors and a tag, … This is explained in detail in the system overview linked to in point 4.

  3. Anchors will forward the needed data to neighboring anchors. This will make the

  4. The main role of the initiator is to start the TDMA cycle.

2 Likes
4

Guys:

Thanks for the answers. I appreciate it a lot!

There is another question. Are the superframe duration of 100ms and the location rate capacity of 150 Hz the same for different data rates like 110K and 850 K ?

Warmest regards

5

Hello Andre

This is also outlined in the system overview. See section 2, “Summery Performance”:

The data rate of the PANS system is fixed at 6.81Mbps, and thus the superframe duration is also fixed.

It is however possible to set the location rate per tag. This impact the amount of tags that can be located since the size of the superframe is fixed, meaning it is possible to have e.g:
750 tags @ 0.2 Hz
150 tags @ 1 Hz
15 tags @ 10 Hz
etc.

The minimal sampling rate is 0.0167Hz, allowing to use 9000 tags. In theory it is possible to sample 1 tag @150Hz, but I’m not sure if the location engine of the tag will be quick enough. The maximum location rate is 10Hz, allowing to use 15 tags.

The DW1000 can use different data rates, but this is not supported by PANS.