Methods for mobility related handover in NR
A method of operating a user equipment, UE, according to some embodiments includes receiving a handover, HO, command, to perform a handover to a target cell, wherein the HO command includes a mobility configuration for lower layer mobility associated to multiple physical cell identities, PCIs, configured for the target cell, and applying the HO command including the mobility configuration. A method of operating a first network node includes receiving a HO request from a second network node to handover a UE to the first network node, the HO request including measurement information associated to multiple cells or multiple PCIs associated to the first network node, generating a HO command that includes a mobility configuration for lower layer mobility associated to multiple PCIs configured for the target cell, and transmitting the HO command to the second network node for delivery to the UE.
1 . A method of operating a user equipment, UE, the method comprising:
receiving a handover, HO, command, to perform a handover to a target cell, wherein the HO command comprises a mobility configuration for lower layer mobility associated to multiple physical cell identities, PCIs, configured for the target cell, wherein the lower layer mobility is used to trigger a change of at least a cell or a PCI upon reception of a lower layer signaling; and
applying the HO command including the mobility configuration.
2 . The method of claim 1 , wherein the mobility configuration for lower layer comprises a dedicated configuration, wherein the dedicated configuration is applied upon reception of the lower layer signaling indicating a change of PCI and/or a change of cell for the UE, wherein the dedicated configuration comprises TCI states associated to PCI(s) that can be different from the PCIs configured for the target cell.
3 . The method of claim 1 , wherein the HO command comprises an RRCReconfiguration including a Reconfiguration WithSync information element.
4 . The method of claim 1 , wherein the lower layer signaling comprises a medium access control, MAC, control element, CE.
5 . The method of claim 1 , wherein the mobility configuration for lower layer comprises a cell configuration that is different from a cell configuration for the target cell, wherein the cell configuration is applied upon reception of a lower layer signaling indicating a change of cell for the UE.
6 . The method of claim 1 , wherein the mobility configuration is provided using delta signaling that indicates changes from an existing mobility configuration of the UE.
7 . The method of claim 1 , wherein the HO command comprises a contention free random access, CFRA, configuration associated to a plurality of beams of the target cell indicated in the HO command.
8 . The method of claim 7 , wherein respective ones of the plurality of beams are associated to different physical cell identifiers.
9 . The method of claim 7 , further comprising:
performing a random access procedure to the target cell using the CFRA configuration, wherein performing the random access procedure comprises:
selecting a beam for transmitting a random access preamble based on the CFRA configuration;
determining resources on the selected beam for transmitting the random access preamble;
transmitting the preamble on the determined resources of the selected beam;
receiving a random access response in response to the preamble; and
transmitting a reconfiguration complete message in response to the random access response.
10 . The method of claim 9 , wherein selecting the beam comprises at least one of:
prioritizing a PCI or a cell identified in the CFRA configuration;
selecting a synchronization signal block, SSB, or channel state information reference signal, CSI-RS, associated to any PCI and/or cell configured in the CFRA configuration; and
selecting a SSB or CSI-RS according to an order of priority provided in the CFRA configuration.
11 . The method of claim 10 , wherein selecting the beam comprises selecting a beam based on a power measurement associated with the beam being above a threshold.
12 . The method of claim 11 , wherein the power measurement comprises a reference signal received power, RSRP, measurement.
13 . The method of claim 11 , wherein the threshold is configured with one of: per SSB per PCI, per CSI-RS per PCI, per PCI, for both contention free random access, CFRA, and contention based random access, CBRA, and per PCI and/or cell for CFRA and per PCI and/or cell for CBRA.
14 . The method of claim 1 , wherein the mobility configuration comprises a set of common random access parameters for a plurality of different PCIs.
15 . The method of claim 1 , wherein the mobility configuration comprises a CBRA configuration associated to a plurality of beams in the target cell.
16 . The method of claim 15 , wherein respective ones of the plurality of beams are associated to different PCIs.
17 . The method of claim 1 , wherein the mobility configuration comprises a CBRA configuration and a CFRA configuration, the method further comprising:
determining whether a configured beam has a power measurement associated above a predetermined threshold and is either configured for CFRA or is associated to a high priority; and
selecting the configured beam.
18 . The method of claim 17 , further comprising, if it is determined that no configured beam has a power measurement associated above the predetermined threshold and is either configured for CFRA or is associated to a high priority, determining whether a configured beam is either configured for CBRA or is associated to a high priority; and
selecting the configured beam.
19 . The method of claim 18 , further comprising, if it is determined that no configured beam is either configured for CBRA or is associated to a high priority, determining whether a configured beam has a CFRA configuration; and
selecting the configured beam.
20 . The method of claim 17 , further comprising:
selecting a random access resource associated with the selected beam.