User Equipment Duplicate Message Handling
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Solution Overview
Problem
In communication systems, user equipment (UE) experiences call setup failures due to receiving duplicate messages during state transitions, primarily caused by re-establishment in the Radio Link Control (RLC) layer of the access stratum, leading to unnecessary failure notifications and call abortions.
Innovation Solution
The UE implements a method to detect duplicate messages by checking for an indication attached to subsequent messages after RRC layer re-establishment of a signaling radio bearer, discarding such messages without transmitting failure notifications to prevent procedure failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transmits a failure notification upon receiving a duplicate message during state transition, then the protocol error is detected and reported, but the call setup procedure fails and is aborted
Solution Approach 1:
The patent converts the harmful effect of duplicate message reception (which causes call setup failure) into a beneficial outcome by introducing an indication mechanism. When the RRC layer re-establishes a signaling radio bearer, it provides an indication to the NAS layer that a duplicate message may follow. Upon receiving such indication, the NAS layer can identify and silently discard duplicate messages while still detecting the protocol anomaly, thus converting the harmful failure condition into a manageable situation that maintains call setup success.
2Productivity
If the UE silently discards duplicate messages without failure notification, then the call setup procedure continues successfully, but the duplicate message detection capability is reduced
Solution Approach 1:
The patent introduces an intermediary mechanism in the form of an indication flag passed from the RRC layer to the NAS layer. This indication acts as a mediator that prepares the NAS layer to expect and handle duplicate messages appropriately. The indication does not eliminate duplicate message detection capability; rather, it enables the NAS layer to distinguish between legitimate messages and expected duplicates, allowing selective discarding while maintaining detection awareness.
3Reliability
If the RRC layer re-establishes the signaling radio bearer, then the radio link quality is improved, but duplicate messages are generated at the NAS layer
Solution Approach 1:
The patent applies preliminary action by having the RRC layer provide an indication to the NAS layer before the duplicate message is received. When the RRC layer re-establishes the signaling radio bearer to improve radio link quality, it proactively notifies the NAS layer that a duplicate message may follow. This preliminary notification allows the NAS layer to prepare and correctly handle the incoming duplicate message, preventing call setup failure while maintaining the beneficial radio link re-establishment.
Data Source
AI summary
A method of handling messages at a user equipment received from a communications network during a procedure, the method implemented at the user equipment comprising: receiving a first message from the network while the user equipment is in a first operating state; processing the first message and entering a second operating state in response to receiving the first message; receiving a second message from the network while the user equipment is in the second operating state; detecting that the second message is a duplicate of the first message; and checking for an indication that the second message is a potential duplicate of the first message. If the indication is not present, the method further comprises transmitting a failure notification to the network. If the indication is present, the method further comprises discarding the second message and not transmitting a failure notification to the network to prevent failure of the procedure.