8.7.15 E-UTRA – NR Cell Resource Coordination

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

8.7.15.1 General

The purpose of the E-UTRA – NR Cell Resource Coordination procedure is to enable coordination of radio resource allocation between an eNB and an en-gNB that are sharing spectrum and whose coverage areas are fully or partially overlapping. During the procedure, the eNB and en-gNB shall exchange their intended resource allocations for data traffic, and, if possible, converge to a shared resource. The procedure is only to be used for the purpose of E-UTRA – NR spectrum sharing.

The procedure uses non-UE-associated signalling.

8.7.15.2 Successful Operation

Figure 8.7.15.2-1: eNB-initiated E-UTRA – NR Cell Resource Coordination request, successful operation

Figure 8.7.15.2-2: en-gNB-initiated E-UTRA – NR Cell Resource Coordination request, successful operation

If case of network sharing with multiple cell ID broadcast with shared X2-C signalling transport, as specified in TS 36.300 [15], the E-UTRA – NR CELL RESOURCES COORDINATION REQUEST message and the E-UTRA – NR CELL RESOURCES COORDINATION RESPONSE message shall contain the Interface Instance Indication IE to identify the corresponding interface instance.

eNB initiated E-UTRA – NR Cell Resource Coordination:

An eNB initiates the procedure by sending the E-UTRA – NR CELL RESOURCE COORDINATION REQUEST message to an en-gNB over the X2 interface. The en-gNB extracts the Data Traffic Resource Indication IE and it replies by sending the E-UTRA – NR CELL RESOURCE COORDINATION RESPONSE message. The en-gNB shall calculate the full eNB resource allocation by combining the Data Traffic Resource Indication IE and the Protected E-UTRA Resource Indication IE that were most recently received from the eNB.

In case of conflict between the most recently received Data Traffic Resource Indication IE and the most recently received Protected E-UTRA Resource Indication IE, the en-gNB shall give priority to the Protected E-UTRA Resource Indication IE.

If the Initiating Node Type is eNB, then the E-UTRA – NR CELL RESOURCE COORDINATION REQUEST message shall contain at least one EUTRA Cell ID in the List of E-UTRA Cells in NR Coordination Request. If the Initiating Node Type is en-gNB, then the E-UTRA – NR CELL RESOURCE COORDINATION REQUEST message shall contain at least one NR-Cell ID in the List of NR Cells in NR Coordination Request.

en-gNB initiated E-UTRA – NR Cell Resource Coordination:

An en-gNB initiates the procedure by sending the E-UTRA – NR CELL RESOURCE COORDINATION REQUEST message to an eNB. The eNB replies with the E-UTRA – NR CELL RESOURCE COORDINATION RESPONSE message. The en-gNB shall calculate the full eNB resource allocation by combining the Data Traffic Resource Indication IE and the Protected E-UTRA Resource Indication IE that were most recently received from the eNB.

In case of conflict between the most recently received Data Traffic Resource Indication IE and the most recently received Protected E-UTRA Resource Indication IE, the en-gNB shall give priority to the Protected E-UTRA Resource Indication IE.