CSFB Prepaging Guard Timer for Call Setup Efficiency
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in handling mobile terminated calls during Circuit Switch Fallback (CSFB) transitions, particularly due to the inability of prepaging to function effectively in these scenarios, leading to unnecessary resource usage and call setup inefficiencies.
Innovation Solution
A method and apparatus for delivering mobile terminated calls that involve sending a PRN Ack message before completing the paging request, utilizing a guard timer to manage call forwarding processes, and integrating with LTE networks to handle CSFB operations during prepaging, ensuring efficient resource utilization and call setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If prepaging is implemented to page the UE during the PRN procedure, then call setup efficiency is improved, but it cannot function effectively with CSFB leading to resource waste
Solution Approach 1:
The patent applies preliminary action by sending the PRN Ack message containing the roaming number before the paging procedure is fully completed. The VMSC sends the PRN Ack to the HLR in advance, allowing the HLR to forward the calling UE's number to the GMSC提前, so that when paging eventually completes and the UE is reached, the call path is already prepared, maintaining call setup efficiency while accommodating CSFB requirements
Solution Approach 2:
The patent introduces dynamic timing control through a guard timer mechanism. The VMSC starts a guard timer when sending the paging request and dynamically adjusts when to send the PRN Ack based on whether the timer expires before or after paging completes. This dynamic approach allows the system to adapt to different scenarios (UE answers quickly vs. UE takes longer) and ensures prepaging works effectively with CSFB without wasting resources
2Reliability
If the call path is set up through the wireless network to the termination MSC before paging, then call delivery is ensured, but network resources are wasted if the UE does not accept the call
Solution Approach 1:
The patent applies preliminary action by preparing the call path information (roaming number) in advance through the PRN Ack message sent before paging completes. However, the actual call path setup through the wireless network to the termination MSC is deferred until after the UE is successfully paged and confirms availability. This ensures call delivery assurance is prepared in advance while avoiding premature resource allocation that would waste energy if the UE rejects the call
3Manufacturing precision
If the PRN Ack message is sent after paging completion, then call path accuracy is ensured, but call setup time increases
Solution Approach 1:
The patent applies preliminary action by sending the PRN Ack message with the roaming number before paging completion. This allows the HLR to prepare the call path information in advance. The call path accuracy is maintained because the VMSC can still verify and complete the paging procedure first, and only send the PRN Ack once paging is confirmed or timeout occurs, thus balancing early preparation with accuracy assurance
Solution Approach 2:
The patent uses dynamic timing control with a guard timer to balance call path accuracy and setup time. If the guard timer expires before paging completes, the VMSC sends the PRN Ack early (reducing setup time). If paging completes before timeout, the VMSC waits and sends PRN Ack after confirmation (ensuring accuracy). This dynamic approach optimizes both parameters based on actual paging progress
Data Source
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AI summary
A method and apparatus for delivering a mobile terminated call to user equipment (UE) in a circuit switched fall back (CSFB) capable wireless network system using prepaging. When the visiting mobile switching center (VMSC) registered in the home location register (HLR) of the called UE receives a provide roaming message (PRN) from the HLR indicating that a CS call to the UE has been originated at a gateway mobile switching center (GMSC), the VMSC starts a paging process with a mobility management entity (MME) then returns a mobile station roaming number (MSRN) to the HLR when it receives a SGs service request indicating that the called UE is in EMM-connected mode. Alternatively, the VMSC sets a guard timer in response to the SGs service request and returns the MSRN to the HLR when the guard timer expires. In the meantime, the VMSC remain in a paging stage waiting for the response from the UE falling back to the UMTS/GSM network from the LTE network.