EPS Bearer Suspension for Packet Switched Service Continuity
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Solution Overview
Problem
Current mobile communication systems face challenges in providing seamless packet switched service continuity during circuit switched fallback operations, particularly due to the lack of dual transfer mode support, which results in suspended PS services during CSFB transitions, especially when handovers occur to networks that do not support DTM.
Innovation Solution
The solution involves the UE performing a GPRS suspend procedure when handover to a non-3GPP access network is necessary, allowing for the handover of all or selected PDN connections from E-UTRAN to the non-3GPP access network, and using mechanisms like MAPCON and IFOM to manage PS bearers, ensuring service continuity by maintaining suspended bearers over E-UTRAN or GERAN/UTRAN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover to non-3GPP access network is performed during CSFB operation, then PS service continuity is improved, but device complexity increases due to need for dual transfer mode support and coordination between multiple networks
Solution Approach 1:
The patent extracts the PS service management functionality from the UE by introducing a network-side mechanism where the MME suspends and manages EPS bearers during CSFB operations. This removes the need for complex DTM support in the UE, as the network handles the bearer suspension and resumption automatically.
Solution Approach 2:
The MME acts as an intermediary between the E-UTRAN and GERAN/UTRAN networks, coordinating the PS service continuity during CSFB. The MME receives indications from the target network about DTM support and manages the bearer suspension/resumption process, eliminating the need for direct UE involvement in complex inter-network coordination.
2Ease of operation
If DTM is not supported in target network, then ease of operation is improved, but PS service suspension occurs during CSFB transitions
Solution Approach 1:
The patent implements preliminary action by having the MME proactively suspend EPS bearers before the CSFB handover occurs, based on an indication from the target network that DTM is not supported. This preemptive suspension prevents service disruption during the transition, and the bearers are automatically resumed after the CS call completes.
3Adaptability or versatility
If PS bearers are suspended during CSFB, then adaptability to non-DTM networks is improved, but loss of time occurs during service resumption
Solution Approach 1:
The patent maintains continuity of useful action by keeping the EPS bearer contexts suspended rather than fully released during CSFB operations. The bearers remain in a suspended state with their configuration preserved, allowing for rapid resumption after the CS call without requiring full re-establishment, thus minimizing service interruption time.
Data Source
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Figure 3
Figure 3A
AI summary
Methods and apparatus to provide packet switched service continuity during circuit switched fallback operation are described. One example method includes determining that a target system does not support packet switched handover; determining if non- 3GPP access for packet switched service is available; and triggering handover to the non-3GPP access.