Session Management Back-Off Timer Control for PLMN Reconnection
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Solution Overview
Problem
In mobile communication networks, when a packet data network connection request is rejected, mobile terminals often attempt to reconnect simultaneously across different mobile network codes, leading to futile mass connection attempts that negatively impact user experience and system load, as existing solutions do not effectively manage reconnection attempts across equivalent PLMNs with different mobile network codes.
Innovation Solution
A method and system where a network element generates a response message to a mobile terminal rejecting a packet data network connection request, including information on equivalent PLMNs and individual timer values for each, indicating the period during which reconnection attempts are restricted, allowing for differentiated rejection periods based on cause codes and network conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single back-off timer is applied to one mobile network code, then network resource utilization is controlled for that specific code, but mobile terminals moving between cells with different equivalent mobile network codes will reset the back-off condition and make futile reconnection attempts
Solution Approach 1:
The patent segments the back-off timer mechanism by creating separate timers for each mobile network code in the equivalent PLMN list. Instead of a single timer affecting all equivalent codes, each code now has its own timer instance, allowing independent control of reconnection attempts per code while maintaining the overall back-off functionality across equivalent networks.
Solution Approach 2:
The patent applies local quality by making the back-off condition specific to each mobile network code rather than universal across all equivalent codes. The rejection parameters (timer values, cause codes) are localized to individual codes, allowing differentiated control where each code's reconnection behavior is independently managed based on its specific network conditions.
2Adaptability or versatility
If mobile terminals are allowed to attempt reconnection across different equivalent PLMNs, then mobility functionality is maintained, but mass simultaneous attempts occur when terminals move between cells, negatively impacting user experience and system load
Solution Approach 1:
The patent implements preliminary action by pre-configuring the network with a list of equivalent PLMNs and their associated back-off parameters before reconnection attempts occur. When a connection is rejected, the terminal receives advance information about which equivalent PLMNs are subject to back-off conditions and for how long, allowing it to proactively suppress reconnection attempts during mobility events rather than reacting to each failure individually.
Solution Approach 2:
The patent employs feedback mechanisms where the network provides rejection messages containing cause codes and timer information back to the mobile terminal. This feedback loop allows the terminal to understand why a connection was rejected and how long it should wait before attempting reconnection on equivalent PLMNs, creating a controlled feedback-driven reconnection strategy that prevents mass simultaneous attempts.
Data Source
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AI summary
The invention relates to a solution for controlling of a mobile terminal to request an establishment of a packet data network connection to a public land mobile network. A method according to the solution comprises: receiving (310), in a network element, a packet data network connection re-quest from the mobile terminal (150); generating (320), by the network element, a response message rejecting the packet data network connection request, wherein the response message comprises information element indicating if the rejection is applicable in at least one other public land mobile network than the one into which the mobile terminal (150) is registered to; and transmitting (330) the generated message to the mobile terminal (150). The invention also relates to a network element and a system implementing at least part of the method.