Access Domain Selection During Inter-RAT Transitions
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Solution Overview
Problem
During an ongoing Inter-Radio Access Technology (IRAT) procedure, multimode mobile phones face challenges in selecting the proper access domain for Mobile Originated (MO) calls, leading to increased call rejection probabilities due to the indeterminate currently used RAT.
Innovation Solution
Defer Access Domain Selection (ADS) until the IRAT procedure is completed, using guard timers to ensure a proper access domain is chosen, considering factors like device states, user preferences, and network indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If Access Domain Selection is performed during an ongoing IRAT procedure, then the MO call can be established quickly, but the call may be rejected due to indeterminate RAT state
Solution Approach 1:
The patent applies preliminary action by checking whether an IRAT procedure is ongoing before performing Access Domain Selection. The system proactively identifies the problematic condition (ongoing IRAT) and prevents the harmful action (ADS during IRAT) from occurring, thereby avoiding call rejection while maintaining quick establishment when conditions are favorable
2Reliability
If Access Domain Selection is deferred until IRAT procedure completes, then call rejection probability decreases, but call establishment time increases
Solution Approach 1:
The patent implements dynamics by making the Access Domain Selection timing adaptive rather than static. The system dynamically adjusts when to perform ADS based on the IRAT procedure state: immediately when no IRAT is ongoing (fast path), or after IRAT completion (deferred path). This dynamic approach optimizes both speed and reliability by selecting the appropriate timing based on real-time conditions
Data Source
AI summary
A mobile communication device with a processor is provided. The processor determines whether an Inter-Radio Access Technology (IRAT) procedure is ongoing when receiving a request for a Mobile Originated (MO) call, starts a first guard timer in response to the IRAT procedure being ongoing, and performs an Access Domain Selection (ADS) for making the MO call in response to the IRAT procedure being completed and the first guard timer not expiring.