Restoring Packet Data Connectivity During GSM to UMTS Handover
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Solution Overview
Problem
Always-on user equipment in 3GPP networks faces challenges in maintaining packet data connectivity during transitions between networks that do not support concurrent voice and data to those that do, particularly after GSM to UMTS handovers or reselections, leading to delayed restoration of data connectivity and unreachability from packet data perspectives.
Innovation Solution
The method involves performing a routing area update with PDP context status information immediately after a GSM to UMTS handover or reselection, and sending a small packet to push servers after a voice call handover to detect changes in PDP contexts and restore preferred connections, ensuring continuous connectivity by monitoring transitions to networks that support concurrent voice and data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the user equipment performs GSM to UMTS handover or reselection, then voice service continuity is maintained, but packet data connectivity is lost or delayed
Solution Approach 1:
The patent applies preliminary action by performing a routing area update procedure immediately after GSM to UMTS handover or reselection, before any data transmission is attempted. This proactive update ensures the network has current location information and can restore PDP contexts promptly, eliminating the delay that would otherwise occur until the first data transmission attempt.
Solution Approach 2:
The patent implements feedback by monitoring the status of PDP contexts after handover and triggering appropriate update procedures based on whether the handover was successful and whether the UE is in idle or active mode. This feedback mechanism ensures connectivity is restored appropriately in different scenarios without unnecessary signaling.
2Reliability
If the user equipment does not perform routing area update immediately after handover, then signaling overhead is reduced, but push service availability is compromised
Solution Approach 1:
The patent applies dynamics by adapting the routing area update behavior based on the UE's operational state. In idle mode, the UE performs update only when transitioning to a network that supports concurrent voice and data. In active voice call mode, the UE performs update immediately after handover. This dynamic adaptation ensures push service availability without unnecessary signaling in stable conditions.
Solution Approach 2:
The patent changes the routing area update parameter behavior based on network capability detection. When the UE detects it has transitioned to a UMTS network that supports concurrent voice and data, it activates the update procedure. This parameter change approach ensures push service availability only when network conditions warrant it, avoiding unnecessary signaling overhead.
3Reliability
If the user equipment suspends packet session during voice call in GSM, then voice call quality is maintained, but data connectivity is lost until call ends
Solution Approach 1:
The patent applies preliminary action by restoring the packet data session and performing routing area update during the voice call handover to UMTS, rather than waiting until the call ends. This allows the data session to be re-established in advance, so when the voice call terminates, data connectivity is immediately available without delay.
4Adaptability or versatility
If the user equipment transitions from GPRS to UMTS network, then concurrent voice and data support is enabled, but PDP context compatibility issues arise
Solution Approach 1:
The patent implements feedback by monitoring handover success and network type changes, then triggering routing area update procedures to restore PDP contexts. The UE detects when it has successfully handed over to UMTS and when it is in idle or active mode, and performs appropriate updates to ensure PDP context compatibility between GPRS and UMTS networks.
Data Source
AI summary
A method and apparatus to restore always on connectivity to user equipment, the method having the steps of: monitoring whether the user equipment has transitioned to a network that supports concurrent voice and data; performing, upon the monitoring step detecting the transition, a routing area update; checking whether the user equipment was in a voice call at the time of the transition, and if yes, sending a data packet to the network.