PGW Reselection for Network Slice Compatibility in 5G
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Solution Overview
Problem
In 5G wireless systems, the mobility management entity (MME) may select a packet data network gateway (PGW) that supports the requested access point name (APN)/data network name (DNN) but not the network slice subscribed by the user, leading to EPS to 5GS mobility failure.
Innovation Solution
A PGW can reject a Create Session Request from the MME if it does not support the user's subscribed network slice, and provide the Fully Qualified Domain Name (FQDN) or IP address of another PGW that supports the correct network slice, allowing the MME to re-establish the PDN connection with the correct PGW.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the MME selects a PGW based on APN/DNN support, then the PGW can provide the requested data network access, but the PGW may not support the user's subscribed network slice, causing mobility failure
Solution Approach 1:
The patent applies preliminary action by having the PGW proactively check whether it supports the user's subscribed network slice before the mobility failure occurs. When the PGW receives a Create Session Request, it retrieves the user's subscription information and verifies network slice compatibility in advance. If the PGW does not support the required network slice, it rejects the session request with a specific cause code, allowing the MME to select a different PGW that does support the network slice, thus preventing mobility failure before it happens.
2Reliability
If the PGW rejects the Create Session Request with a specific cause code, then the MME can select a correct PGW supporting the network slice, but the session establishment process requires additional rejection and re-establishment steps
Solution Approach 1:
The patent implements feedback by introducing a specific cause code (cause code 36: 'PGW does not support the network slice subscribed by the UE') in the Create Session Response message. This feedback mechanism provides the MME with precise information about why the session establishment failed, enabling the MME to immediately select a different PGW that supports the required network slice. The feedback loop closes when the MME uses this information to make an informed reselection decision, reducing unnecessary trial-and-error attempts.
Data Source
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AI summary
Systems, methods, apparatuses, and computer program products for packet data network gateway (PGW) selection for network slicing are provided.