Multi-SIM RRC Resume Timing for Inactive Context Retention
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Solution Overview
Problem
In multi-SIM user equipment (UE) operations, the premature termination of an RRC resume procedure on one SIM due to a high-priority service request on another SIM leads to loss of RRC INACTIVE context and potential context mismatch, causing inefficiencies and resource wastage.
Innovation Solution
The UE delays the execution of a multi-SIM suspend request until a response to the RRC resume request is received from the network, allowing it to maintain the RRC INACTIVE state and minimize signaling, thereby optimizing network resource usage and power savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE immediately executes the multi-SIM suspend request when a high-priority service is triggered on the second SIM, then the high-priority service can be established quickly, but the RRC INACTIVE context on the first SIM is lost and causes RRC context mismatch between the UE and the first network
Solution Approach 1:
The UE performs preliminary action by transmitting the RRC resume request to the network before executing the multi-SIM suspend request. This ensures that the resume procedure is initiated and the RRC context is maintained with the network, while still allowing the high-priority service on the second SIM to be established. The suspend request is executed only after the RRC resume request has been transmitted, preventing context mismatch.
2Reliability
If the UE delays the execution of the multi-SIM suspend request until RRC resume response is received, then the RRC INACTIVE context is maintained and signaling is minimized, but the high-priority service on the second SIM is delayed
Solution Approach 1:
The UE applies partial action by transmitting the RRC resume request without waiting for the complete resume procedure to finish. This partial execution of the resume procedure is sufficient to maintain the RRC context with the network, while the UE can simultaneously proceed with the high-priority service setup on the second SIM. The multi-SIM suspend request is executed after the resume request transmission, achieving a balance between context maintenance and service speed.
3Productivity
If the UE ends the RRC resume procedure prematurely to provide Layer 1 resources to the second SIM, then the high-priority service can be established, but the RRC INACTIVE context is lost and unnecessary signaling occurs
Solution Approach 1:
The UE performs preliminary action by transmitting the RRC resume request to the network before suspending the procedure. This ensures that the network is notified of the resume intent and the RRC context is maintained, avoiding the need for future context restoration signaling. The multi-SIM suspend request is then executed to allocate Layer 1 resources to the second SIM for the high-priority service, achieving efficient resource allocation without losing the RRC context or generating unnecessary signaling.
Data Source
AI summary
A user equipment (UE) configured to enter an RRC INACTIVE state on a first network using a first SIM and an RRC INACTIVE or RRC IDLE state on a second network using a second SIM, initiate an RRC resume including a resume request including a cause indication on the first SIM, during the RRC resume, decode a trigger for a service on the second SIM having a higher priority than the RRC resume, based on the trigger, initiate a multi-SIM suspend procedure on the first SIM, the multi-SIM suspend procedure including a multi-SIM suspend request from the NAS entity of the first SIM to the RRC entity of the first SIM and, at the RRC entity of the first SIM, delay an execution of the multi-SIM suspend request6 until a response to an RRC resume request is received from the first network.