Positioning Calculation Function

In Release 15, the PCF (Positioning Calculation Function) was newly introduced as a distinct logical function within the positioning architecture, with its key characteristic defined by where the position calculation is performed, either as an MS-based PCF or a network-based PCF. The release also standardized interactions for PCF discovery and selection, and introduced support for specific PCF services, including Npcf_UEPolicyControl and Npcf_EventExposure. Furthermore, procedures were defined for PCF-initiated AM Policy association termination and PCF resource cleanup.

• Clarification on PCF selection TS 23.501CR0015
• Alignment of PCF selection description TS 23.501CR0435
• Update to PCF discovery and selection TS 23.501CR0597
• Interactions with PCF - Updates to reference architecure for interworking TS 23.501CR0639
• Clarification on DN authorization data between PCF and SMF TS 23.501CR0726
• Addition of PCF services Npcf_UEPolicyControl and Npcf_EventExposure TS 23.501CR0904

+ 27 more changes

In Release 16, the PCF (Positioning Calculation Function) saw its role expanded to support new service requirements, including the transport of Time-Sensitive Networking (TSN) information and TSC assistance information between the SMF and PCF. The release also introduced enhancements for PCF discovery and selection, such as using DNN replacement as a factor and ensuring the same PCF is selected for a given combination of UE ID, S-NSSAI, and DNN. Furthermore, PCF functionality was updated to handle policy control request triggers for TSN and to allow location information retrieval for the GMLC.

• Allowing IMS to use N5 interface to interact with PCF TS 23.228CR1203
• Additional corrections for allowing IMS to use N5 interface to interact with PCF TS 23.228CR1204
• eSBA communication schemas related to PCF discovery and selection TS 23.501CR0802
• Allowing IMS to use N5 interface to interact with PCF TS 23.501CR1134
• 23.501 part of PCF selection for PDU sessions with same DNN and S-NSSAI TS 23.501CR1375
• Location information retrieval for GMLC TS 29.504CR0086

+ 55 more changes

In Release 17, the PCF (Positioning Calculation Function) was enhanced to support a network-based calculation mode as an alternative to mobile-based positioning, as defined in the GPS positioning mechanism. The release also completed the procedures for PCF discovery and registration within the network architecture, including updates for PDU session contexts. Furthermore, it introduced the PCF as a consumer of the Npcf_PolicyAuthorization service to enable new analytics and notification capabilities.

• Selecting the same PCF for AMF and SMF TS 23.501CR2644
• PCF impacts of 5MBS TS 23.501CR2880
• NWDAF instance provisioning to the PCF TS 29.507CR0181
• NWDAF instance provisioning to the PCF TS 29.512CR0849
• PCF control of MPS for DTS TS 29.513CR0257
• Selecting the same PCF for AMF and SMF TS 29.513CR0263

+ 70 more changes

In Release 18, the PCF saw significant enhancements for new positioning services and policy control. Key additions include explicit support for Sidelink (SL) Positioning and Ranging SL Positioning Policy, along with new connection management procedures for user plane positioning. The release also completed the provisioning of slice-related inactivity timers and introduced PCF support for 5GS Packet Delay Variation monitoring exposed to the AF.

• Enhancements of PCF Services and NEF Services TS 23.501CR3796
• PCF support of 5GS Packet Delay Variation monitoring based on QoS monitoring mechanism and exposed to AF TS 23.501CR3792
• PCF provides the Periodicity to SMF via PCC rules for resolving the EN for KI#8 TS 23.501CR4529
• Support of SL Positioning TS 23.501CR4555
• Specifying and adding reference for Ranging/SL Positioning Policy TS 24.526CR0181
• New connection capability for LCS user plane positioning TS 24.526CR0225

+ 39 more changes

In Release 19, key enhancements for the PCF included its new awareness of I-SMF insertion for managing Local Offloading, support for ML model provisioning to the LMF for AI/ML-based positioning, and the ability to handle and pass Non-3GPP device information. The release also introduced mechanisms for UP path event reporting to an AF via the PCF and added specific conditions for the PCF to detect PCEF failures in a timely manner.

• Add the PCRF/PCF-based restoration solution for EPC/5GC NF failure TS 23.380CR0128
• IMS restoration procedure after PCRF/PCF failure TS 23.380CR0130
• PCF's awareness of I-SMF insertion for Local Offloading Management TS 23.501CR5833
• NWDAF model provision for AI positioning TS 23.501CR5635
• Passing non-3gpp device information to the PCF TS 29.512CR1292
• Support of UP path event reporting to AF via PCF TS 29.512CR1327

+ 43 more changes

In Release 20, the PCF (Positioning Calculation Function) saw updates related to its integration with other network functions, specifically concerning the selection of the SMF and PCF for procedures like UIA_ARC. Additionally, corrections were made to the energy consumption calculation models used by the PCF, particularly for scenarios involving redundant transmission or a PDU Session with multiple PDU Session Anchors.

• SMF and PCF Selection for UIA_ARC TS 23.501CR6504
• Correction on Energy Consumption calculation for redundant transmission or PDU Session with multiple PDU Session Anchors TS 23.501CR6522