Methods for reference signal configuration in wireless systems
A method performed by a WTRU may comprise receiving PRS configuration information and performing a first set of measurements based on the PRS configuration. The method may further comprise determining whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria. On a condition that the determining to trigger is affirmative, transmitting an on-demand PRS request. In embodiments, the on-demand PRS criteria may be based on an RSRP, TDoA, number of multipaths, accuracy and/or latency.
1 . A method performed by a wireless transmit/receive unit (WTRU), the method comprising:
receiving positioning reference signal (PRS) configuration information including (i) an initial PRS configuration for one or more transmission/reception points (TRPs) and (ii) information indicating a mapping between the one or more TRPs and associated PRS pre-configuration IDs;
performing, based on the received PRS configuration information, a first set of measurements on a PRS received according to the initial PRS configuration;
determining, by the WTRU, to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria, wherein the on-demand PRS criteria is based on one or more of a reference signal receive power (RSRP), a time difference of arrival (TDoA), or a number of multipath signals;
in response to determining to trigger the on-demand PRS request, selecting, using the mapping, a PRS pre-configuration ID from among the associated PRS pre-configuration IDs, the PRS pre-configuration ID corresponding to a PRS configuration to be requested via the on-demand PRS request, wherein the PRS configuration to be requested is an aperiodic PRS configuration or a semi-persistent PRS configuration; and
transmitting the on-demand PRS request including an indication of the PRS configuration to be requested and the selected PRS pre-configuration ID.
2 . The method of claim 1 , wherein the first set of measurements correspond to one or more cells or TRPs.
3 . The method of claim 1 , wherein the on-demand PRS criteria is further based on a positioning accuracy requirement.
4 . The method of claim 1 , wherein the on-demand PRS criteria is further based on a positioning latency requirement.
5 . The method of claim 1 , wherein the PRS configuration information is received from a Location Management Function (LMF).
6 . The method of claim 1 , wherein the determining, by the WTRU, to trigger the on-demand PRS request is based on one or more configured thresholds.
7 . The method of claim 1 , wherein transmitting the on-demand PRS request further comprises:
transmitting, in the on-demand PRS request, an indication including one or more of a TRP identifier associated with the selected PRS pre-configuration ID or an urgency of the on-demand PRS request, to a serving base station or a Location Management Function (LMF).
8 . The method of claim 1 , further comprising:
on a condition that a confirmation of the request or an on-demand configuration of the request is received:
performing a second set of measurements on one or more resources of the requested or received on-demand PRS configuration; and
transmitting a report including one or more of the second set of measurements or the selected PRS pre-configuration ID to a base station or a Location Management Function (LMF).
9 . A wireless transmit/receive unit (WTRU) comprising:
a transceiver; and
a processor:
wherein the transceiver and the processor are configured to:
receive positioning reference signal (PRS) configuration information including (i) an initial PRS configuration for one or more transmission/reception points (TRPs) and (ii) information indicating a mapping between the one or more TRPs and associated PRS pre-configuration IDs;
perform, based on the received PRS configuration information, a first set of measurements on a PRS received according to the initial PRS configuration;
determine whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria, wherein the on-demand PRS criteria is based on one or more of a reference signal receive power (RSRP), a time difference of arrival (TDoA), or a number of multipath signals;
on a condition that the WTRU determines to trigger the on-demand PRS request, selecting, using the mapping, a PRS pre-configuration ID from among the associated PRS pre-configuration IDs, the PRS pre-configuration ID corresponding to a PRS configuration to be requested via the on-demand PRS request, wherein the PRS configuration to be requested is an aperiodic PRS configuration or a semi-persistent PRS configuration; and
transmit the on-demand PRS request including an indication of the PRS configuration to be requested and the selected PRS pre-configuration ID.
10 . The WTRU of claim 9 , wherein the first set of measurements correspond to one or more cells or TRPs.
11 . The WTRU of claim 9 , wherein the PRS configuration information is received from a Location Management Function (LMF).
12 . The WTRU of claim 9 , wherein the determination of whether to trigger the on-demand PRS request is based on one or more configured thresholds.
13 . The WTRU of claim 9 , wherein the transceiver is further configured to:
transmit, in the on-demand PRS request, an indication including one or more of a TRP identifier associated with the selected PRS pre-configuration ID or an urgency of the on-demand PRS request, to a serving base station or a Location Management Function (LMF).
14 . The WTRU of claim 9 , wherein the transceiver and the processor are further configured to:
perform a second set of measurements on one or more resources of a configured on-demand PRS; and
transmit a report including one or more of the second set of measurements or the selected PRS pre-configuration ID to a base station or a Location Management Function (LMF).
15 . The WTRU of claim 9 , wherein the on-demand PRS criteria is further based on a positioning accuracy requirement.
16 . The WTRU of claim 9 , wherein the on-demand PRS criteria is further based on a positioning latency requirement.