Multi-SIM Modem Paging Gap Detection for Call Reliability
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Solution Overview
Problem
Dual SIM Dual Standby (DSDS) mobile devices can only manage one subscriber identity at a time, leading to missed calls on the other SIM due to limited radiofrequency and baseband modules, resulting in high missed call rates, especially during background activities or signaling procedures.
Innovation Solution
A multi-SIM modem with a control unit that monitors communication activities on one SIM to identify gaps for reading Paging Channel data blocks on the other SIM, allowing for simultaneous monitoring of both SIMs and prioritizing incoming calls by categorizing activities into foreground and background classes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RF module and baseband module are shared by two SIMs in Idle-DRX mode, then device complexity is reduced, but the ability to manage both SIMs simultaneously is lost leading to missed calls
Solution Approach 1:
The patent implements dynamic time-sharing of the single RF and baseband modules between two SIMs. The system dynamically switches between SIM1 and SIM2 based on active communication needs, allowing the same hardware to serve multiple purposes at different times. This dynamic allocation resolves the contradiction by maintaining low device complexity while improving call reception reliability through intelligent resource management.
Solution Approach 2:
The system employs periodic switching between SIMs during Idle-DRX mode, where the RF and baseband modules are allocated to different SIMs in periodic intervals. This periodic action ensures that both SIMs receive adequate attention for paging reception and call setup while sharing the same hardware resources, thus maintaining both low complexity and high reliability.
2Productivity
If the modem is active on one SIM for background activities or signaling, then communication tasks are performed, but the other SIM cannot be monitored leading to missed incoming calls
Solution Approach 1:
The patent segments communication activities into different priority levels and time slots. Background activities and signaling procedures on one SIM are segmented from incoming call monitoring on the other SIM by allocating specific time intervals for each function. This segmentation allows the system to perform background communication tasks while still dedicating periodic intervals to monitor incoming calls on both SIMs.
Solution Approach 2:
The system performs preliminary actions by pre-scheduling paging channel monitoring intervals for both SIMs even when one SIM is engaged in background activities. The modem proactively allocates time slots for PCH reading on the inactive SIM before conflicts arise, ensuring that incoming calls are not missed due to ongoing background communication tasks.
3Stability of the object's composition
If paging channel reading is performed only when both SIMs are in idle mode, then resource conflicts are avoided, but call setup rate decreases when one SIM is active
Solution Approach 1:
The patent changes the operational parameters of the modem by introducing dynamic state transitions between different SIMs. When one SIM is in idle mode, the system changes the state of the RF and baseband modules to actively monitor PCH for that SIM, even if the other SIM is currently active. This parameter change enables the system to maintain stability while improving MT call setup rate by flexibly adapting to different operational conditions.
Data Source
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Figure 3
Figure 4(a)~5(c)
AI summary
There is described a mobile device with a multiple subscriber identity arrangement having a modem (10) capable of receiving messages related to either one of at least two subscriber identities, but not simultaneously. The arrangement further comprises a control unit (13) configured to, when the modem performs communication activity associated with a first subscriber identity: determine whether gaps (40, 44, 50, 54) not allocated for the communication activity associated with the first subscriber identity coincide with paging occasions (41-42, 51-53) associated with a second subscriber identity; and, if at least one gap (44, 54) not allocated for the communication activity associated with the first subscriber identity coincides with at least one paging occasion associated with the second subscriber identity, cause the modem to switch to the second subscriber identity to read one paging message on a paging channel associated with the second subscriber identity.