During the NR Registration procedure, UE will include its support for Dual Active Protocol stack (DAPS) Handover in the UE Capability message. If there is no support for DAPS from UE, then the network will not configure DAPS handover for one more DRBs during the handover procedure.
Below is the message that UE includes in UE Capability, Please note that DAPS handover is introduced in Release-16 of the 3GPP Specification and it is an optional UE feature and UE support is not mandatory.
interFreqDAPS-r16 SEQUENCE {
interFreqAsyncDAPS-r16 ENUMERATED {supported}
interFreqDiffSCS-DAPS-r16 ENUMERATED {supported}
interFreqMultiUL-TransmissionDAPS-r16 ENUMERATED {supported}
interFreqSemiStaticPowerSharingDAPS-Mode1-r16 ENUMERATED {supported}
interFreqSemiStaticPowerSharingDAPS-Mode2-r16 ENUMERATED {supported}
interFreqDynamicPowerSharingDAPS-r16 ENUMERATED {short, long}
interFreqUL-TransCancellationDAPS-r16 ENUMERATED {supported}
}
intraFreqDAPS-r16 SEQUENCE {
intraFreqDiffSCS-DAPS-r16 ENUMERATED {supported}
intraFreqAsyncDAPS-r16 ENUMERATED {supported}
}
| UE Capability IE | Description |
|---|---|
| interFreqDAPS-r16 | Indicates whether the UE supports inter-frequency handover, e.g. support of simultaneous DL reception of PDCCH and PDSCH from source and target cell. A UE indicating this capability shall also support synchronous DAPS handover and single UL transmission for inter-frequency DAPS handover. This is a Conditional IE. |
| interFreqAsyncDAPS-r16 | Indicates whether the UE supports asynchronous DAPS handover. |
| interFreqDiffSCS-DAPS-r16 | indicates whether the UE supports different SCS in source PCell and inter-frequency target PCell in DAPS handover. |
| interFreqMultiUL-TransmissionDAPS-r16 | indicates whether the UE supports simultaneous UL transmission in source PCell and target PCell during a DAPS handover. The UE can include this field only if any of semiStaticPowerSharingDAPS-Mode1-r16, semiStaticPowerSharingDAPSMode2-r16, or dynamicPowersharingDAPS-r16 are included. Otherwise, the UE does not include this field. |
| interFreqSemiStaticPowerSharingDAPS-Mode1-r16 | indicates whether the UE supports semi-static UL power-sharing mode 1 during DAPS handover between source and target cells of the same FR |
| interFreqSemiStaticPowerSharingDAPS-Mode2-r16 | indicates whether the UE supports semi-static UL power-sharing mode 2 during DAPS handover between source and target cells of same FR. It is only applicable to DAPS Handover in synchronous scenarios. The UE only includes this field if semiStaticPowerSharingDAPS-Mode1-r16 is included. Otherwise, the UE does not include this field. |
| interFreqDynamicPowersharingDAPS-r16 | indicates the value of T offset (short or long) that the UE supports for dynamic UL power-sharing during DAPS handover between source and target cells of same FR. The UE only includes this field if semiStaticPowerSharingDAPS-Mode1-r16 is included. Otherwise, the UE does not include this field. |
| interFreqUL-TransCancellationDAPS-r16 | indicates support of canceling UL transmission to the source PCell for inter-frequency DAPS handover. |
| intraFreqDAPS-r16 | Indicates whether UE supports intra-frequency DAPS handover, e.g. support of simultaneous DL reception of PDCCH and PDSCH from source and target cell. A UE indicating this capability shall also support synchronous DAPS handover, single UL transmission, and canceling UL transmission to the source cell for Intra frequency DAPS handover. |
| intraFreqAsyncDAPS-r16 | indicates whether the UE supports asynchronous DAPS handover |
| intraFreqDiffSCS-DAPS-r16 | indicates whether the UE supports different SCS in source PCell and intra-frequency target PCell in DAPS handover. |
| featureSetCombinationDAPS | If this field is present for a band combination, it reports the feature set combination supported for the band combination when any DAPS bearer is configured. |
DAPS Uplink UE Capability Information
| UE Capability IE | Description |
|---|---|
| intraFreqDAPS-UL-r16 | Indicates whether UE supports enhanced uplink capabilities for intra-frequency DAPS handover. The UE only includes this capability signaling if intraFreqDAPSr16 is included in the FeatureSetDownlink for the same FeatureSet. |
| intraFreqDynamicPowersharingDAPS-r16 | indicates the value of T offset (short or long) that the UE supports for dynamic UL power-sharing during DAPS handover between source and target cells of same FR. The UE only includes this field if intraFreqSemiStaticPowerSharingDAPS-Mode1-r16 is included. Otherwise, the UE does not include this field. |
| intraFreqMultiUL-TransmissionDAPS-r16 | indicates whether the UE supports simultaneous UL transmission in source PCell and target PCell during a DAPS handover. The UE only includes this field if any of intraFreqSemiStaticPowerSharingDAPS-Mode1-r16, intraFreqSemiStaticPowerSharingDAPS-Mode2-r16 or intraFreqDynamicPowersSharingDAPS-r16 are included. Otherwise, the UE does not include this field. |
| intraFreqSemiStaticPowerSharingDAPS-Mode1-r16 | indicates whether the UE supports semi-static UL power-sharing mode 1 during DAPS handover between source and target cells of the same FR. |
| intraFreqSemiStaticPowerSharingDAPS-Mode2-r16 | indicates whether the UE supports semi-static UL power-sharing mode 2 during DAPS handover between source and target cells of same FR. It is only applicable to DAPS Handover in synchronous scenarios. The UE only includes this field ifintraFreqSemiStaticPowerSharingDAPS-Mode1-r16 is included. Otherwise, the UE does not include this field. |
| intraFreqTwoTAGs-DAPS-r16 | indicates whether the UE supports different timing advance groups in source PCell |
In Release-16 3GPP has also introduced Condition Handover CHO, I have discussed that in detail in the below Post.