SMF Data Usage Updates During UPF and Session Function Changes
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Solution Overview
Problem
In 6G communication systems, there is a need to effectively monitor data usage when a user plane function (UPF)/session management function (SMF) for a session and service continuity mode 3 PDU session is changed, as existing methods fail to accurately reflect data used in the remaining allowed usage value.
Innovation Solution
A session management function (SMF) entity is provided with a transceiver and processor to determine changes in target UPF or SMF, transmitting update requests to a policy control function (PCF) to update remaining allowed usage, and manage data usage monitoring through various events and triggers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If UPF/SMF is changed during SSC mode 3 PDU session, then session continuity is maintained, but data usage monitoring accuracy deteriorates
Solution Approach 1:
The SMF transmits accumulated data usage information to the PCF before the UPF/SMF change is completed. This preliminary action ensures that the PCF has the most current data usage information available, allowing accurate remaining allowed usage calculation even as the session transitions to new network functions.
Solution Approach 2:
The system implements a feedback mechanism where the SMF continuously monitors data usage and provides updates to the PCF. When a UPF/SMF change is detected, the SMF feeds back the accumulated data usage information to the PCF, which then recalculates and updates the remaining allowed usage value, ensuring continuous monitoring accuracy throughout the session lifecycle.
2Measurement precision
If data usage information is continuously updated during UPF/SMF change, then monitoring accuracy is improved, but signaling overhead increases
Solution Approach 1:
The SMF transmits the accumulated data usage information to the PCF in advance, before the UPF/SMF change is finalized. This preliminary transmission ensures that the PCF receives the data usage information at the right moment without requiring continuous updates during the entire change process, thus reducing signaling overhead while maintaining monitoring accuracy.
3Adaptability or versatility
If remaining allowed usage is calculated after UPF/SMF change, then session mobility is improved, but data usage reflection accuracy deteriorates
Solution Approach 1:
The SMF transmits the accumulated data usage information to the PCF before the UPF/SMF change is completed. This ensures that the PCF has the accurate data usage information from the previous session phase, which will be used to calculate the remaining allowed usage after the change, preventing information loss and ensuring accurate reflection of total data usage.
Solution Approach 2:
The PCF receives feedback from the SMF containing the accumulated data usage information and uses this feedback to calculate the remaining allowed usage value after the UPF/SMF change. This feedback mechanism ensures that the calculation incorporates all data usage information from the entire session history, not just the post-change period, maintaining accuracy while enabling session mobility.
Data Source
AI summary
A session management function (SMF) entity related to a first protocol data unit (PDU) session between a user equipment (UE) and a data network (DN) for a network slice, for monitoring data usage is provided. The SMF entity includes a transceiver, and at least one processor coupled with the transceiver and configured to determine to change at least one of a target user plane function (UPF) or a target SMF for connectivity between the UE and the DN for the network slice, transmit an update request message including accumulated data usage information for the first PDU session to a policy control function (PCF) configured to update remaining allowed usage, based on the determining to change at least one of the target UPF or the target SMF, and receive a response message from the PCF, the remaining allowed usage being updated based on the accumulated data usage information.