8.7.21 EN-DC Resource Status Reporting Initiation

36.4233GPPEvolved Universal Terrestrial Radio Access Network (E-UTRAN)Release 17TSX2 Application Protocol (X2AP)

8.7.21.1 General

This procedure is used by the eNB to request the reporting of load measurements to the en-gNB .

The procedure uses non UE-associated signalling.

8.7.21.2 Successful Operation

8.7.21.2.1 Successful Operation – eNB-initiated

Figure 8.7.21.2-1: EN-DC Resource Status Reporting Initiation, successful operation – eNB-initiated

The procedure is initiated with an EN-DC RESOURCE STATUS REQUEST message sent from the eNB to the en-gNB to start a measurement, stop a measurement, add cells to report for a measurement.

If the Report Characteristics EN-DC IE is included in the EN-DC RESOURCE STATUS REQUEST message and indicates cell specific measurements, the NR Cell To Report EN-DC List IE shall be included.

Upon receipt of the EN-DC RESOURCE STATUS REQUEST message, the en-gNB:

– shall initiate the requested measurement according to the parameters given in the request in case the Registration Request EN-DC IE set to "start"; or

– shall stop all cells measurements and terminate the reporting in case the Registration Request EN-DC IE is set to "stop"; or

– shall add cells indicated in the NR Cell To Report EN-DC List IE list to the measurements initiated before for the given measurement IDs, in case the Registration Request EN-DC IE is set to "add". If measurements are already initiated for a cell indicated in the NR Cell To Report EN-DC List IE, this information shall be ignored.

The en-gNB shall send an EN-DC RESOURCE STATUS RESPONSE message to the eNB to indicate that all of the requested measurement objects the measurement can be initiated.

Interaction with other procedures

When starting a measurement, the Report Characteristics EN-DC IE in the EN-DC RESOURCE STATUS REQUEST indicates the type of objects en-gNB shall perform measurements on. For each cell, the en-gNB shall include in the EN-DC RESOURCE STATUS UPDATE message:

– the NR Radio Resource Status IE, if the first bit, "PRB Periodic" of the Report Characteristics EN-DC IE included in the EN-DC RESOURCE STATUS REQUEST message is set to "1". If the cell for which NR Radio Resource Status IE is requested to be reported supports more than one SSB, the NR Radio Resource Status IE for such cell shall include the SSB Area Radio Resource Status Item IE for all SSB areas supported by the cell. If the SSB To Report List IE is included for a cell, the NR Radio Resource Status IE for such cell shall include the requested SSB Area Radio Resource Status List IE.

– the TNL Capacity Indicator IE, if the second bit, "TNL Capacity Ind Periodic" of the Report Characteristics EN-DC IE included in the EN-DC RESOURCE STATUS REQUEST message is set to "1". The received TNL Capacity Indicator IE represents the lowest TNL capacity available for the cell, only taking into account interfaces providing user plane transport.

– the NR Composite Available Capacity Group IE, if the third bit, "Composite Available Capacity Periodic" of the Report Characteristics EN-DC IE included in the EN-DC RESOURCE STATUS REQUEST message is set to "1". If Cell Capacity Class Value IE is included within the NR Composite Available Capacity Group IE, this IE is used to assign weights to the available capacity indicated in the Capacity Value IE. If the cell for which NR Composite Available Capacity Group IE is requested to be reported supports more than one SSB, and if the SSB To Report List IE is included for a cell, the NR Composite Available Capacity Group IE for such cell shall include the requested SSB Area Capacity Value List IE, providing the SSB area capacity with respect to the Cell Capacity Class Value.

If the Reporting Periodicity EN-DC IE in the EN-DC RESOURCE STATUS REQUEST is present, this indicates the periodicity for the reporting of periodic measurements. The en-gNB shall only report more than once if the Reporting Periodicity EN-DC IE is included.

8.7.21.2.2 Successful Operation – en-gNB-initiated

Figure 8.7.21.2-2: EN-DC Resource Status Reporting Initiation, successful operation – en-gNB-initiated

The procedure is initiated with an EN-DC RESOURCE STATUS REQUEST message sent from the en-gNB to the eNB to start a measurement, stop a measurement, add cells to report for a measurement.

If the Report Characteristics EN-DC IE is included in the EN-DC RESOURCE STATUS REQUEST message and indicates cell specific measurements, the E-UTRA Cell To Report EN-DC List IE shall be included.

Upon receipt of the EN-DC RESOURCE STATUS REQUEST message, the eNB:

– shall initiate the requested measurement according to the parameters given in the request in case the Registration Request EN-DC IE set to "start"; or

– shall stop all cells measurements and terminate the reporting in case the Registration Request EN-DC IE is set to "stop"; or

– shall add cells indicated in the E-UTRA Cell To Report EN-DC List IE list to the measurements initiated before for the given measurement IDs, in case the Registration Request EN-DC IE is set to "add". If measurements are already initiated for a cell indicated in the E-UTRA Cell To Report EN-DC List IE, this information shall be ignored. The eNB shall ignore the E-UTRA Cell To Report EN-DC List IE, if included.

The eNB shall send an EN-DC RESOURCE STATUS RESPONSE message to the en-gNB to indicate that all of the requested measurement objects the measurement can be initiated.

Interaction with other procedures, en-gNB-initiated operation

When starting a measurement, the Report Characteristics EN-DC IE in the EN-DC RESOURCE STATUS REQUEST indicates the type of objects eNB shall perform measurements on. For each cell, the eNB shall include in the EN-DC RESOURCE STATUS UPDATE message:

– the Radio Resource Status IE, if the first bit, "PRB Periodic" of the Report Characteristics EN-DC IE included in the RESOURCE STATUS REQUEST message is set to "1";

– the S1 TNL Load Indicator IE, if the second bit, "TNL Load Ind Periodic" of the Report Characteristics EN-DC IE included in the RESOURCE STATUS REQUEST message is set to "1";

– the Hardware Load Indicator IE, if the third bit, "HW Load Ind Periodic" of the Report Characteristics EN-DC IE included in the RESOURCE STATUS REQUEST message is set to "1";

– the Composite Available Capacity Group IE, if the fourth bit, "Composite Available Capacity Periodic" of the Report Characteristics EN-DC IE included in the RESOURCE STATUS REQUEST message is set to "1". If the Cell Capacity Class Value IE is included within the Composite Available Capacity Group IE, this IE is used to assign weights to the available capacity indicated in the Capacity Value IE;

If the Reporting Periodicity EN-DC IE in the EN-DC RESOURCE STATUS REQUEST is present, this indicates the periodicity for the reporting of periodic measurements. The eNB shall only report more than once if the Reporting Periodicity EN-DC IE is included.

8.7.21.3 Unsuccessful Operation

Figure 8.7.21.3-1: EN-DC Resource Status Reporting Initiation, unsuccessful operation – eNB-initiated

Figure 8.7.21.3-2: EN-DC Resource Status Reporting Initiation, unsuccessful operation – en-gNB-initiated

If any of the requested measurements cannot be initiated, the en-gNB or the eNB shall send an EN-DC RESOURCE STATUS FAILURE message.

8.7.21.4 Abnormal Conditions

Void.