Dual SIM Paging Collision Resolution via Forced Cell Reselection
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Solution Overview
Problem
Multi-SIM wireless communication devices often experience paging collisions due to overlapping paging occasions, leading to missed calls or packet channel assignments, as they can only receive one paging message at a time with a single RF device.
Innovation Solution
The method involves detecting probable paging collisions and using forced cell reselection or paging message position recomputation to ensure all SIMs can receive paging messages by selecting a non-serving cell with stronger signal strength or altering the paging message position based on Temporary Mobile Subscriber Identity (TMSI) instead of International Mobile Subscriber Identity (IMSI).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RF device is used to receive paging messages for multiple SIMs, then device complexity is reduced, but paging collision occurs when paging occasions overlap
Solution Approach 1:
The patent implements dynamic cell reselection for SIMs experiencing paging collisions. The system monitors paging occasion overlaps and triggers forced cell reselection when collisions are detected, allowing the device to adaptively change the serving cell for affected SIMs. This dynamic adjustment resolves the contradiction by maintaining single RF device operation while preventing paging message loss through real-time parameter changes.
Solution Approach 2:
The patent changes paging-related parameters (cell identity, paging occasion timing) when collisions are detected. By modifying the serving cell parameters for SIMs involved in paging collisions, the system shifts their paging occasions to non-overlapping time slots. This parameter change approach allows the single RF device to receive all paging messages without requiring additional hardware.
2Ease of operation
If paging occasions for multiple SIMs are scheduled independently, then each SIM can have optimal paging timing, but paging collision occurs when occasions overlap in time
Solution Approach 1:
The patent implements a feedback mechanism where the system monitors paging occasion schedules for all SIMs and detects when overlaps occur. Upon detecting a paging collision, the system triggers forced cell reselection for the affected SIM, which changes its paging occasion timing. This feedback loop ensures that paging occasions are dynamically adjusted to prevent message loss while maintaining independent scheduling capabilities.
Solution Approach 2:
The patent performs preliminary detection of paging collisions before they cause message loss. By monitoring the scheduling of paging occasions in advance and identifying potential overlaps, the system can proactively trigger cell reselection to prevent the collision from occurring. This preliminary anti-action approach maintains independent scheduling while preventing information loss.
3Reliability
If forced cell reselection is performed to resolve paging collision, then paging message reception is improved, but call establishment time increases due to cell reselection delay
Solution Approach 1:
The patent performs cell reselection in advance when paging collisions are detected, before any paging messages are lost. By proactively changing the serving cell and adjusting paging occasion timing beforehand, the system prevents the need for reselection after a collision occurs. This preliminary action reduces the time penalty by avoiding post-collision recovery procedures.
Solution Approach 2:
The patent implements dynamic cell reselection that is triggered only when paging collisions are detected, rather than performing reselection continuously or periodically. This on-demand dynamic approach minimizes the time penalty by avoiding unnecessary cell changes while still resolving collisions promptly when they occur, thus maintaining both reliability and timing efficiency.
Data Source
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AI summary
Methods and devices for resolving paging collisions in a communication device (105-1) are described. The method includes detecting a probable paging collision between two subscriber identity modules (SIMs) (115) of the communication device (105-1) and determining whether at least one SIM of the communication device (105-1) has a non-serving cell in a corresponding broadcast control channel (BCCH) allocation list (BA-list). Further, the method includes ascertaining, based on one or more selection parameters, whether the at least one SIM can be selected for forced cell reselection and indicating, based on the ascertaining, exclusion of a currently serving cell of a SIM selected for the forced cell reselection from normal cell reselection procedure. Further, the forced cell reselection is initiated for the selected SIM. Further in some embodiments, if none of the SIMs can be selected for a forced cell reselection, then a Paging Message Position (PMP) recomputation Request is sent to a network controller to change the paging block position computation from IMSI-based computation to TMSI-based computation.