QoS Parameter Mapping for EPS to 5GS Handover
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Solution Overview
Problem
The challenge lies in establishing a direct mapping of aggregate Quality of Service (QoS) parameters between the Evolved Packet System (EPS) and 5G System (5GS) networks during handovers, as the EPS network uses a single Access Point Name (APN) Aggregate Maximum Bit Rate (AMBR) for all sessions in a Packet Data Network (PDN), while the 5GS network controls each packet data unit session independently, leading to inconsistencies in QoS parameter usage.
Innovation Solution
A method and communications entity are introduced to determine authorized APN AMBR by summing authorized session AMBRs of PDU sessions, allowing for seamless QoS parameter mapping by calculating the authorized APN AMBR based on subscribed and session AMBRs, ensuring consistent QoS parameter usage across network transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single authorized APN AMBR is used for all sessions in a PDN connection in EPS network, then bandwidth control is simplified and easier to manage, but it cannot provide fine-grained QoS control for individual sessions compared to 5GS network
Solution Approach 1:
The patent segments the aggregate APN AMBR control into individual session AMBR controls. Each PDU session in 5GS network has its own authorized session AMBR, which can be independently controlled and mapped to EPS bearers. This segmentation enables fine-grained QoS control while maintaining the aggregate APN AMBR limit, resolving the contradiction between simplicity and granularity.
Solution Approach 2:
The patent transforms the QoS parameter representation from a single aggregate APN AMBR value in EPS to multiple session-specific AMBR values in 5GS. During handover, the network converts between these parameter forms by summing individual session AMBRs to derive the aggregate APN AMBR, enabling seamless transition while preserving control precision.
2Speed
If direct mapping of QoS parameters is attempted between EPS and 5GS networks during handover, then handover speed is improved, but mapping errors occur due to different aggregate control granularities
Solution Approach 1:
The patent introduces an intermediary conversion mechanism during handover that translates between EPS APN AMBR and 5GS session AMBR representations. The network entity calculates the aggregate APN AMBR by summing individual session AMBRs and uses this converted parameter for bearer establishment, ensuring accurate QoS mapping without direct one-to-one parameter correspondence.
Solution Approach 2:
The patent performs preliminary calculation of the aggregate APN AMBR by summing all authorized session AMBRs before establishing EPS bearers during handover. This advance computation ensures that the correct aggregate bandwidth limit is applied from the start, preventing mapping errors and ensuring reliable QoS parameter transfer.
3Measurement precision
If individual session AMBRs are controlled independently in 5GS network, then QoS precision for each session is improved, but the complexity of QoS parameter management increases compared to EPS network
Solution Approach 1:
The patent merges multiple individual session AMBR controls into a single aggregate APN AMBR control during EPS handover. By summing the authorized session AMBRs of all PDU sessions, the network creates a unified APN AMBR value that simplifies EPS bearer management while preserving the precision benefits of individual session control in the 5GS network.
Data Source
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AI summary
This application provides a parameter determining method and a communications entity. The method includes: When UE is in a system in which an EPS network and a 5GS network interwork, the UE is currently located in the 5GS network, and used QoS parameters include an authorized UE AMBR and an authorized session AMBR of a session. Because of movement of the UE, the UE needs to be handed over to the EPS network, and QoS parameters that need to be used for the UE in the EPS network include an authorized UE AMBR and an authorized APN AMBR. The authorized APN AMBR is determined by a first communications entity based on at least one of a subscribed APN AMBR and the authorized session AMBR of the PDU session, and the authorized UE AMBR is determined by a second communications entity based on the authorized APN AMBR. Therefore, a method for regenerating a QoS parameter when the UE is handed over from the 5GS network to the EPS network is provided.