Centralized time synchronization for time difference of arrival (TDOA) using ultra-wideband (UWB)
In some implementations, a server may obtain metric information from each of a group of RF positioning anchors, wherein the metric information of a respective RF positioning anchor comprises information regarding: a time source accessible to the respective RF positioning anchor, a ground truth accuracy of a known location of the respective RF positioning anchor, a clock stability of the respective RF positioning anchor, a geographic location of the respective RF positioning anchor, a prevalence of Line of Sight (LoS) links of the respective RF positioning anchor, or power consumption information of the respective RF positioning anchor, or a combination thereof. The server may select the synchronization reference anchor from the group of RF positioning anchors based at least in part on the metric information. The server may transmit information indicative of the selected synchronization reference anchor to each RF positioning anchor of the group of RF positioning anchors.
1 . A method of designating a synchronization reference anchor for a group of radio frequency (RF) positioning anchors to enable downlink Time Difference of Arrival (DL-TDoA) positioning of mobile devices, the method comprising:
obtaining, at a server, metric information from each RF positioning anchor of the group of RF positioning anchors, wherein the metric information of a respective RF positioning anchor comprises information indicating:
a time source accessible to the respective RF positioning anchor,
a ground truth accuracy of a known location of the respective RF positioning anchor,
a clock stability of the respective RF positioning anchor,
a geographic location of the respective RF positioning anchor,
power consumption information of the respective RF positioning anchor, or a combination thereof,
determining a weighted-closeness centrality value for each RF positioning anchor of the group of RF positioning anchors, wherein the weighted-closeness centrality value for each RF positioning anchor is based on:
the metric information of the respective RF positioning anchor, and
a value indicative of a number of hops of the respective RF positioning anchor to a plurality of other RF positioning anchors of the group of RF positioning anchors;
selecting, at the server, the synchronization reference anchor from the group of RF positioning anchors based at least in part on the weighted-closeness centrality value; and
transmitting information indicative of the selected synchronization reference anchor to each RF positioning anchor of the group of RF positioning anchors.
2 . The method of claim 1 , wherein each RF positioning anchor of the group of RF positioning anchors comprises a UWB anchor.
3 . The method of claim 2 , wherein the server comprises a Connected Intelligent Edge (CIE).
4 . The method of claim 2 , wherein group of RF positioning anchors comprises a cluster of UWB anchors, and the synchronization reference anchor comprises an Init-anchor.
5 . The method of claim 2 , wherein group of RF positioning anchors comprises a network of two or more clusters of UWB anchors and the synchronization reference anchor comprises a Global-anchor.
6 . The method of claim 1 , wherein selecting the synchronization reference anchor is further based at least in part on information regarding a cost metric (CM) for each RF positioning anchor of the group of RF positioning anchors.
7 . The method of claim 1 , wherein each RF positioning anchor of the group of RF positioning anchors comprises a Fifth Generation (5G) New Radio (NR) anchor.
8 . The method of claim 7 , wherein the server comprises a Location Management Function (LMF).
9 . The method of claim 1 , wherein obtaining the metric information from each RF positioning anchor of the group of RF positioning anchors comprises:
sending a request for the metric information from the server to each RF positioning anchor of the group of RF positioning anchors; and
responsive to sending the request, receiving metric information at the server from each RF positioning anchor of the group of RF positioning anchors.
10 . The method of claim 9 , wherein sending the request for the metric information and receiving the metric information is performed using an out-of-band (OOB) message of an RF technology different than an RF technology used by the RF positioning anchors to provide the DL-TDoA positioning.
11 . The method of claim 1 , further comprising sending, to each RF positioning anchor of the group of RF positioning anchors, information indicative of the weighted-closeness centrality value to the respective RF positioning anchor.
12 . The method of claim 1 , further comprising transmitting timing information to enable each RF positioning anchor of the group of RF positioning anchors to synchronize with the selected synchronization reference anchor.
13 . A server comprising:
a transceiver;
a memory; and
one or more processors communicatively coupled with the transceiver and the memory, wherein the one or more processors are configured to:
obtain metric information from each radio frequency (RF) positioning anchor of a group of RF positioning anchors, wherein the metric information of a respective RF positioning anchor comprises information indicating:
a time source accessible to the respective RF positioning anchor,
a ground truth accuracy of a known location of the respective RF positioning anchor,
a clock stability of the respective RF positioning anchor,
a geographic location of the respective RF positioning anchor,
power consumption information of the respective RF positioning anchor, or
a combination thereof,
determine a weighted-closeness centrality value for each RF positioning anchor of the group of RF positioning anchors, wherein the weighted-closeness centrality value for each RF positioning anchor is based on:
the metric information of the respective RF positioning anchor, and
a value indicative of a number of hops of the respective RF positioning anchor to a plurality of other RF positioning anchors of the group of RF positioning anchors;
select a synchronization reference anchor from the group of RF positioning anchors based at least in part on the weighted-closeness centrality value; and
transmit, via the transceiver, information indicative of the selected synchronization reference anchor to each RF positioning anchor of the group of RF positioning anchors.
14 . The server of claim 13 , wherein each RF positioning anchor of the group of RF positioning anchors comprises a UWB anchor.
15 . The server of claim 14 , wherein the server comprises a Connected Intelligent Edge (CIE).
16 . The server of claim 13 , wherein selecting the synchronization reference anchor is further based at least in part on information regarding a cost metric (CM) for each RF positioning anchor of the group of RF positioning anchors.
17 . The server of claim 13 , wherein each RF positioning anchor of the group of RF positioning anchors comprises a Fifth Generation (5G) New Radio (NR) anchor and the server comprises a Location Management Function (LMF).
18 . The server of claim 13 , wherein, to obtain the metric information from each RF positioning anchor of the group of RF positioning anchors, the one or more processors are configured to:
send a request for the metric information from the server to each RF positioning anchor of the group of RF positioning anchors; and
responsive to sending the request, receiving metric information at the server from each RF positioning anchor of the group of RF positioning anchors.
19 . The server of claim 18 , wherein the one or more processors are configured to send the request for the metric information and receive the metric information using an out-of-band (OOB) message of an RF technology different than an RF technology used by the RF positioning anchors to provide a DL-TDoA positioning.
20 . The server of claim 13 , wherein the one or more processors are further configured to send, to each RF positioning anchor of the group of RF positioning anchors, information indicative of the weighted-closeness centrality value to the respective RF positioning anchor.
21 . The server of claim 13 , wherein the one or more processors are further configured to transmit timing information to enable each RF positioning anchor of the group of RF positioning anchors to synchronize with the selected synchronization reference anchor.
22 . An apparatus for designating a synchronization reference anchor for a group of radio frequency (RF) positioning anchors to enable downlink Time Difference of Arrival (DL-TDoA) positioning of mobile devices, the apparatus comprising:
means for obtaining metric information from each RF positioning anchor of the group of RF positioning anchors, wherein the metric information of a respective RF positioning anchor comprises information indicating:
a time source accessible to the respective RF positioning anchor,
a ground truth accuracy of a known location of the respective RF positioning anchor,
a clock stability of the respective RF positioning anchor,
a geographic location of the respective RF positioning anchor,
power consumption information of the respective RF positioning anchor, or
a combination thereof,
means for determining a weighted-closeness centrality value for each RF positioning anchor of the group of RF positioning anchors, wherein the weighted-closeness centrality value for each RF positioning anchor is based on:
the metric information of the respective RF positioning anchor, and
a value indicative of a number of hops of the respective RF positioning anchor to a plurality of other RF positioning anchors of the group of RF positioning anchors;
means for selecting the synchronization reference anchor from the group of RF positioning anchors based at least in part on the weighted-closeness centrality value; and
means for transmitting information indicative of the selected synchronization reference anchor to each RF positioning anchor of the group of RF positioning anchors.
23 . The apparatus of claim 22 , wherein selecting the synchronization reference anchor is based at least in part on information regarding a cost metric (CM) for each RF positioning anchor of the group of RF positioning anchors.
24 . The apparatus of claim 22 , wherein each RF positioning anchor of the group of RF positioning anchors comprises a Fifth Generation (5G) New Radio (NR) anchor and the apparatus comprises a Location Management Function (LMF).
25 . The apparatus of claim 22 , wherein the means for obtaining the metric information from each RF positioning anchor of the group of RF positioning anchors comprises:
means for sending a request for the metric information to each RF positioning anchor of the group of RF positioning anchors; and
means for, responsive to sending the request, receiving metric information from each RF positioning anchor of the group of RF positioning anchors.
26 . The apparatus of claim 22 , further comprising means for transmitting timing information to enable each RF positioning anchor of the group of RF positioning anchors to synchronize with the selected synchronization reference anchor.
27 . A non-transitory computer-readable medium storing instructions for designating a synchronization reference anchor for a group of radio frequency (RF) positioning anchors to enable downlink Time Difference of Arrival (DL-TDoA) positioning of mobile devices, the instructions comprising code for:
obtaining metric information from each RF positioning anchor of the group of RF positioning anchors, wherein the metric information of a respective RF positioning anchor comprises information indicating:
a time source accessible to the respective RF positioning anchor,
a ground truth accuracy of a known location of the respective RF positioning anchor,
a clock stability of the respective RF positioning anchor,
a geographic location of the respective RF positioning anchor,
power consumption information of the respective RF positioning anchor, or
a combination thereof,
determining a weighted-closeness centrality value for each RF positioning anchor of the group of RF positioning anchors, wherein the weighted-closeness centrality value for each RF positioning anchor is based on:
the metric information of the respective RF positioning anchor, and
a value indicative of a number of hops of the respective RF positioning anchor to a Plurality of other RF positioning anchors of the group of RF positioning anchors;
selecting the synchronization reference anchor from the group of RF positioning anchors based at least in part on the weighted-closeness centrality value; and
transmitting information indicative of the selected synchronization reference anchor to each RF positioning anchor of the group of RF positioning anchors.