Mobile Termination Roaming Forwarding Call Setup Delay
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Solution Overview
Problem
Current wireless communication systems face delays and resource wastage in delivering mobile terminated calls during inter-VLR location updates, as the call routing mechanism often fails to accurately redirect calls to the new location area, leading to incomplete call setups and inefficient network usage.
Innovation Solution
Implementing a Mobile Termination Roaming Forwarding (MTRF) mechanism that allows the old VMSC to request routing information from the new VMSC, enabling direct call forwarding from the old VMSC to the new VMSC during location updates, thereby avoiding rerouting and reducing setup delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the old VMSC pages the mobile device during a mobile terminated call, then the call setup process is initiated, but the mobile device cannot be located in the original location area due to ongoing location update, resulting in failed call delivery
Solution Approach 1:
The old VMSC receives the cancel location message from HLR indicating the mobile device has moved to a new location area. Before attempting to page the mobile device, the old VMSC proactively forwards the mobile terminated call to the new VMSC using the new location area information received in the cancel location message. This preliminary forwarding action prevents the failed paging attempt and reduces call setup delay.
Solution Approach 2:
The HLR acts as an intermediary that provides the new location area information to the old VMSC through the cancel location message. This intermediary mechanism enables the old VMSC to obtain accurate routing information without having to page the mobile device in the old location area, thereby improving call delivery reliability.
2Reliability
If the GMSC reroutes the call to the new VMSC after failed paging, then the call can be delivered to the mobile device, but two serial calls must be placed which wastes network resources and introduces delay
Solution Approach 1:
The old VMSC performs the call forwarding action in advance, before the paging failure occurs. By using the new location area information from the HLR to forward the call to the new VMSC proactively, the system avoids the need for serial call attempts and reduces network resource waste.
Solution Approach 2:
The HLR provides feedback to the old VMSC through the cancel location message, indicating that the mobile device has moved to a new location area. This feedback mechanism enables the old VMSC to adjust its call delivery strategy and forward the call directly to the new VMSC, avoiding unnecessary paging attempts and improving network resource efficiency.
3Ease of operation
If the HLR returns routing information for the old VMSC to the GMSC, then the call routing follows the standard procedure, but the call is routed to the wrong VMSC since the mobile device has already moved to a new location area
Solution Approach 1:
The old VMSC receives the cancel location message from HLR before attempting call delivery. It proactively uses the new location area information to forward the call to the new VMSC, ensuring routing accuracy without complicating the overall call routing procedure.
Solution Approach 2:
The HLR serves as an intermediary that provides accurate routing information to the old VMSC through the cancel location message. This intermediary mechanism ensures that the old VMSC has up-to-date location information for accurate call routing, while maintaining the simplicity of the standard call routing procedure.
Data Source
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AI summary
A method for delivering a mobile terminated call to a mobile device communicating with a mobile switching center (MSC) in one example comprises steps of attempting to deliver the mobile terminated call to a mobile device, receiving a message that the mobile device is no longer in the location area served by the visiting MSC and forwarding the mobile terminated call to a different visiting MSC. The mobile terminated call is forwarded directly from one VMSC to another VMSC without requiring two potentially international calls to be placed serially from the GMSC to a VMSC. This method of Mobile Termination Roaming Forwarding can reduce substantial delay in call setup while saving network resources during establishment of the first call.