Mobility Management Entity S-NSSAI Mapping for EPC to 5GC Handover
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Solution Overview
Problem
There is no existing solution for determining Single Network Slice Selection Assistance Information (S-NSSAI) to establish a Protocol Data Unit (PDU) session when a terminal is handed over from an Evolved Packet Core (EPC) supporting a Dedicated Core Network (DCN) to a 5G Core (5GC) network slice.
Innovation Solution
A method where a mobility management entity obtains information about a PDN connection established in the EPC, determines the corresponding S-NSSAI, and uses this information to establish a PDU session in the target 5GC network slice, either by pre-configured correspondence or by requesting it from control plane or network storage entities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal is handed over from EPC supporting DCN to 5GC supporting network slice, then network connectivity is maintained, but there is no existing solution to determine S-NSSAI for PDU session establishment
Solution Approach 1:
The patent introduces a mapping relationship as an intermediary mechanism between the APN parameter in EPC and the S-NSSAI parameter in 5GC. This mapping relationship acts as a bridge that enables the mobility management entity to convert the APN information from the handover request into the corresponding S-NSSAI, thereby solving the problem of determining S-NSSAI during network slice handover without disrupting existing connectivity procedures
Solution Approach 2:
The patent establishes the mapping relationship between APN and S-NSSAI in advance before the handover occurs. By pre-configuring this mapping relationship in the mobility management entity, the system prepares the necessary transformation rules ahead of time, enabling seamless conversion during handover without requiring real-time complex calculations or additional signaling
2Ease of operation
If APN parameter is used in EPC for PDN connection, then connection establishment is simple, but S-NSSAI determination is complex during handover to 5GC
Solution Approach 1:
The patent addresses the parameter transformation issue by establishing a clear mapping relationship between the APN parameter (used in EPC) and the S-NSSAI parameter (used in 5GC). This parameter change mechanism allows the mobility management entity to systematically convert the APN information from the handover request into the corresponding S-NSSAI, making the determination process manageable and systematic rather than complex and ad-hoc
3Productivity
If multiple network slices share AMF entities, then network resource utilization is improved, but session establishment complexity increases
Solution Approach 1:
The patent applies segmentation by establishing separate mapping relationships between APN and S-NSSAI for different network slices. Each network slice can have its own mapping relationship configured in the mobility management entity, allowing independent management and selection of S-NSSAI for each slice. This segmentation approach enables the system to handle multiple slices sharing AMF entities while maintaining clear, manageable session establishment procedures for each slice
Data Source
AI summary
The present disclosure relates to session establishment methods, systems, and devices. One example method includes obtaining, by a first mobility management entity, information about a packet data network (PDN) connection that has been established when a terminal accesses an evolved packet core (EPC) network, and obtaining, by the first mobility management entity, single network slice selection assistance information (S-NSSAI) of a network slice corresponding to the PDN connection.