5G Network Slice Interworking for 4G Session Continuity

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Solution Overview

Problem

Current interworking between 5GS network slicing and EPC connectivity does not support efficient maintenance of existing packet data unit sessions when user equipment moves between 5G and 4G networks, leading to potential session drops and inadequate customization for seamless service continuity.

Innovation Solution

Implement mechanisms such as enhanced Network Slice Selection Policies (NSSP) to map applications to network slices and access point names, maintain PDN connections and S-NSSAI mappings, configure AMF with slice mappings, and augment UE usage types in the home subscriber server to ensure seamless connectivity across networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current interworking solutions between 5GS network slicing and EPC connectivity are used, then basic connectivity is provided, but session continuity is lost when user equipment moves between 5G and 4G networks

Engineering Contradiction:

Improvesession continuityVSAvoidnetwork mobility support

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a mapping mechanism that acts as an intermediary between 5GS network slicing concepts (S-NSSAI, DNN) and EPC connectivity concepts (APN). This mapping entity translates and correlates the different network parameters, enabling seamless session maintenance during mobility between 5G and 4G networks while preserving session continuity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If network slicing concepts are implemented in 5GS, then service customization is enabled, but interworking with EPC becomes complex due to concept differences

Engineering Contradiction:

Improveservice customizationVSAvoidinterworking complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the interworking complexity by changing the parameter representation through mapping relationships. Instead of directly handling complex 5GS network slicing parameters (S-NSSAI, DNN) in EPC, the system maps these to equivalent EPC parameters (APN), simplifying the interworking while preserving service customization capabilities.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If dedicated EPC core network support is implemented, then network slice connectivity is maintained, but system complexity increases

Engineering Contradiction:

Improvenetwork slice connectivityVSAvoidcore network configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal mapping mechanism that can handle multiple network slice scenarios through a single APN mapping framework. This multi-functional approach allows the system to support various network slice configurations and mobility scenarios without requiring separate dedicated configurations for each case, thereby reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12635019B2Mechanism to enable interworking between network slicing and evolved packet core connectivity

Publication Date: 2026.05.19 QUALCOMM INC

AI summary

Aspects of the present disclosure relate to a mechanism to enable interworking between fifth generation system (5GS) network slicing and evolved packet core (EPC) connectivity. In an example, techniques are provided for existing packet data unit (PDU) sessions that provide connectivity to a network slice from a set of network slices. Connectivity to the network slice is in response to a user equipment (UE), that uses network slices, moving between a 5G network and a 4G network. The existing PDU sessions are connected to a dedicated EPC core network that supports the same services provided by the network slice.