Section: 5.9.2.2 Reporting at Presence Reporting Area entering and leaving
Content: In some use cases policy control/charging decisions, such as QoS modification or charging rate change depend on whether the UE is located inside or outside a specific area of interest (Presence Reporting Area), and especially on whether the UE enters or leaves that specific area of interest. A Presence Reporting Area can be: - Either a "UE-dedicated Presence Reporting Area", defined in the subscriber profile and composed of a short list of TAs/RAs, or eNodeBs and/or cells/SAs in a PLMN; - Or a "Core Network predefined Presence Reporting Area", predefined in MME/SGSN and composed of a short list of TAs/RAs, or eNodeBs and/or cells/SAs in a PLMN. NOTE 1: eNodeBs are identified via the Global eNodeB ID IE defined in TS 36.413[ Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 Application Protocol (S1AP) ]  [36]. NOTE 2: Change of UE presence in Presence Reporting Area reporting does not apply to roaming. The reporting of changes of UE presence in Presence Reporting Area is for a specific UE and is triggered as defined in TS 23.203[ Policy and charging control architecture ]  [6]. The PDN GW may request to Start/Stop reporting of changes of UE presence for one or more Presence Reporting Area(s) by using the Presence Reporting Area Action parameter. For UE-dedicated Presence Reporting Areas, the reporting request (Start) shall contain the PRA identifier(s) and the list(s) of TAs/RAs, or eNodeBs and/or cells/SAIs composing the Presence Reporting Area(s). For Core Network predefined Presence Reporting Areas, the reporting request (Start) shall contain the PRA identifier(s). The request to Stop a reporting contains the PRA identifier(s). Each Core Network predefined Presence Reporting Area can be configured with a priority level in the MME/S4-SGSN. In order to prevent overload, the MME/S4-SGSN may set the reporting for one or more of the received Presence Reporting Area(s) to inactive under consideration of the priority configured for each of Core Network predefined Presence Reporting Area(s), while storing the reporting request for this Presence Reporting Area in the user context. Upon reception of a request for change of UE presence in Presence Reporting Area reporting, the MME/S4-SGSN shall report to the PDN GW via the SGW the Presence Reporting Area Information comprising the PRA identifier(s) and indication(s) on whether the UE is inside or outside the Presence Reporting Area(s). If the UE is in ECM-IDLE state, the MME may either bring the UE into ECM-CONNECTED state, or, report based on the UE's last known location and when the UE was there. One or more Presence Reporting Area may be set for a given PDN connection at a time. The serving node if needed only sets the reporting of UE presence in a Presence Reporting Area to inactive when receiving the reporting request for this Presence Reporting Area. If the MME/S4-SGSN decides to set the reporting of UE presence in one or more of the received Presence Reporting Area(s) to inactive, the MME/S4-SGSN shall also report the inactive Presence Reporting Area(s). The MME/S4-SGSN shall notify the PDN GW when the UE enters or leaves a Presence Reporting Area, and no notifications are sent for UE movements inside or outside a Presence Reporting Area. The report of the change of UE presence in Presence Reporting Area shall contain the Presence Reporting Area Information comprising the PRA identifier(s) and indication(s) on whether the UE is inside or outside the area(s). A report shall be sent if the UE presence is different to the last one reported. The MME/S4-SGSN may be configured with a PRA identifier which refers to a Set of Core Network predefined Presence Reporting Areas. The PDN GW may request Start reporting for this Set of Presence Reporting Areas by only indicating this PRA identifier in the Presence Reporting Area Action. When the Presence Reporting Area(s) to be reported belong to a set of Core Network predefined Presence Reporting Areas in which the MME/S4-SGSN is requested to report on change of UE presence, the MME/S4-SGSN shall additionally add to the report the PRA identifier of the Set of Core Network predefined Presence Reporting Areas. Upon change of serving EPC node (MME, S4-SGSN), the PRA identifier(s) and if provided by the PDN GW the list(s) of Presence Reporting Area elements are transferred for all PDN connections as part of MM Context information to the target serving node during the mobility procedure. If one or more Presence Reporting Area(s) was set to inactive, the target serving node may decide to reactivate one or more of the inactive Presence Reporting Area(s). The target serving node indicates per PDN connection to the corresponding PDN GW the PRA identifier(s) and whether the UE is inside or outside the Presence Reporting Area(s) as well as the inactive Presence Reporting Area(s), if any. NOTE 3: The target serving node cannot set the Presence Reporting Area(s) received from the source serving node to inactive.