S1-AP UE Context Preservation via SCTP Failover Signaling
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Solution Overview
Problem
In wireless communication networks, SCTP failures lead to the loss of S1-AP UE contexts, resulting in disruptions such as audio drops and video frame loss, and conventional systems face inefficiencies in processing power and reliability when handling large numbers of connected users.
Innovation Solution
The method involves determining the validity of S1-AP UE contexts after an SCTP failure and communicating this information through S1 Setup Request and Response messages, using optional information elements like hash values to indicate preserved contexts, allowing network nodes to retain and reuse existing UE contexts without resetting all connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SCTP association is lost, then the eNodeB deletes all its UE contexts to ensure data consistency, but this results in audio disruption during Voice over LTE calls and dropped video frames
Solution Approach 1:
The patent segments the UE context management by introducing a context validity indicator that allows the eNodeB to differentiate between valid and invalid UE contexts after SCTP failure. Instead of treating all UE contexts uniformly (deleting them all), the system divides them into valid contexts that can be retained and invalid contexts that need reinitialization, thereby preventing service disruption while maintaining data consistency.
Solution Approach 2:
The patent applies preliminary action by having the eNodeB determine the validity of UE contexts before actually processing them after SCTP failure. The context validity indicator is prepared and included in the S1 Setup Request message in advance, allowing the MME to respond appropriately and avoid disruptive reinitialization of valid contexts.
2Reliability
If the eNodeB resets all connections after SCTP failure, then data consistency is maintained, but this generates nearly a million messages traversing the network for 150,000 connected users
Solution Approach 1:
The patent extracts the context validity information from the traditional S1 Setup procedure by introducing a dedicated context validity indicator. This allows the MME to identify and retain valid UE contexts without processing reinitialization for all 150,000 users, thereby reducing network signaling from nearly a million messages to only the necessary subset of invalid contexts.
Solution Approach 2:
The patent changes the parameter of the S1 Setup Request message by adding a context validity indicator. This parameter change enables the MME to differentiate between valid and invalid UE contexts, allowing selective reinitialization only for invalid contexts rather than resetting all connections, thus dramatically improving network signaling efficiency.
3Duration of action of stationary object
If the eNodeB retains UE contexts after SCTP failure, then service continuity is maintained, but this may cause stranded UE contexts if the MME has deleted them
Solution Approach 1:
The patent implements feedback by having the MME respond to the S1 Setup Request with information about the validity of UE contexts. The MME uses the context validity indicator from the eNodeB to determine which contexts are valid, and this information is fed back to the eNodeB in the S1 Setup Response, ensuring both sides have synchronized context validity information and preventing stranded contexts.
Solution Approach 2:
The context validity indicator serves as an intermediary mechanism between the eNodeB and MME. It carries critical information about UE context validity through the S1 Setup procedure, enabling both nodes to synchronize their understanding of which contexts are valid without direct context exchange, thus maintaining both service continuity and context synchronization.
Data Source
AI summary
According to some embodiments, a method in a network node of a wireless communication network comprises determining that a plurality of S1-AP UE contexts maintained by the network node remain valid after a SCTP failure; generating an S1 Setup Request message comprising an indication that the UE contexts remain valid; and communicating the S1 Setup Request message to a MME. In particular embodiments, a method in an MME comprises receiving an S1 Setup Request message from a network node comprising an indication that UE contexts maintained by the network node remain valid after a SCTP failure. The MME determines a plurality of UE contexts maintained by the MME remain valid after a SCTP failure; generates an S1 Setup Response message comprising an indication that UE contexts maintained by the MME remain valid; and communicates the S1 Setup Response message to the network node.