Mobile Station PDP Context Synchronization Method
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Solution Overview
Problem
In GSM/GPRS networks, the lack of dual transfer mode support leads to asynchronous PDP context status between mobile stations and the network, preventing simultaneous maintenance of circuit-switched and packet-switched connections, resulting in failed GPRS service requests due to unsynchronized PDP context deactivation.
Innovation Solution
A method where the mobile station requests service suspension, deactivates the PDP context after establishing a circuit-switched connection, and informs the network of deactivation status upon service resumption, ensuring synchronized PDP context status through periodic routing area updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the mobile station deactivates the PDP context locally after establishing a circuit-switched connection, then the mobile station can release wireless resources, but the network does not know the PDP context is deactivated, causing asynchronous PDP context status
Solution Approach 1:
The mobile station sends a Routing Area Update Request message to the network after deactivating the PDP context locally. This message includes an information element indicating the PDP context deactivation status, providing feedback to the network so that the network can update its records and maintain synchronous PDP context status with the mobile station.
Solution Approach 2:
The mobile station performs local PDP context deactivation before the circuit-switched connection is fully established or before attempting to re-establish packet-switched service. This preliminary action allows the mobile station to release resources in advance, and then inform the network through the Routing Area Update procedure to ensure status synchronization.
2Loss of information
If the mobile station waits for network response to deactivate PDP context, then PDP context status remains synchronous, but the mobile station cannot establish GPRS connection during GSM call, causing service interruption
Solution Approach 1:
The mobile station performs PDP context deactivation locally in advance, before the GSM call connection is fully established or before packet-switched service is needed. This allows the mobile station to have the PDP context ready for quick reactivation after the call, improving service continuity while maintaining status synchronization through subsequent network notification.
Solution Approach 2:
The mobile station dynamically adjusts the timing of PDP context deactivation and network notification based on the circuit-switched connection status. The deactivation occurs at an optimal moment when it does not block essential signaling, and the network notification is sent when the mobile station can establish a data connection, ensuring both synchronization and service continuity.
3Reliability
If the mobile station re-sends Deactivate PDP Context Request message repeatedly, then the mobile station tries to maintain PDP context deactivation, but the mobile station consumes excessive time and resources waiting for network response
Solution Approach 1:
The mobile station performs local PDP context deactivation immediately without waiting for repeated network responses. This preliminary local action ensures the mobile station can release resources and proceed with circuit-switched service without being blocked by repeated timeout waiting, while still maintaining reliability by notifying the network through the Routing Area Update procedure.
Data Source
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AI summary
A method for synchronously maintaining packet data protocol (PDP) context status between a wireless communication network and a mobile station and an associated mobile station are disclosed to prevent from the asynchronous PDP context status caused by the prior arts. When both the mobile station and the network activate a PDP context for a packet-switched service, if the mobile station is to establish a circuit-switched connection with the network and dual transfer mode (DTM) is not supported, the mobile station will request the network to suspend the packet-switched service. After the circuit-switched connection is established, the mobile station locally deactivates the PDP context. After the circuit-switched connection is disconnected, if the network informs the mobile station that the packet-switched service is resumed, the mobile station will inform the network that the PDP context has been deactivated.