Section: 5.7A.2 Usage Data Reporting for Secondary RAT
Content: When a Secondary RAT can be used in conjunction with E-UTRAN, the HPLMN or VPLMN operator may wish to record the data volume sent on the Secondary RAT. In order to reduce the complexity of this procedure, and to align with existing per EPS bearer accounting procedures, the following principles are used in this release: a) The PLMN locally activates the Secondary RAT Usage Data Reporting by E-UTRAN O&M. The activation can happen separately for Data Volume Reporting of NR and Unlicensed Spectrum. If the PLMN uses this feature, it should ensure that this functionality is supported by all eNodeBs that support NR, Unlicensed Spectrum aggregation (if used to record data volume sent over unlicensed spectrum) as a Secondary RAT. b) The E-UTRAN reports uplink and downlink data volumes to the EPC for the Secondary RAT on a per EPS bearer basis and per time interval. NOTE 1: Secondary RAT includes access type NR and usage data reporting for Secondary RAT includes reporting of the combination of NR usage as defined in TS 37.340[ Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-connectivity; Overall Description; Stage-2 ]  [85]. c) At X2 handover and S1 handover, the source eNodeB reports the data volumes to the EPC. The reported data volume excludes data forwarded to the target RAN node. d) At S1 Release, Connection Suspend, and EPS Bearer Deactivation the eNodeB reports the data volumes to the EPC. e) To assist "partial CDR" generation at the Serving GW and the PDN GW, E-UTRAN O&M can instruct the E-UTRAN to also make periodic reports if no event has triggered a report before the period expires. NOTE 2: The timing of these periodic E-UTRAN reports is not expected to align with the timing of partial CDR generation. Hence the frequency of E-UTRAN reports might be greater than that of partial CDR generation. NOTE 3: RAN needs to be able to partition the measurements in a report to indicate usage that occurred before and after an absolute time. An example of the absolute time is that RAN is configured to partition data usage reports that occurred before and after midnight. f) As an option, the Serving Gateway sends the data volume reports on to PDN GWs identified in bilateral roaming agreements.