MME Backoff Timer for HSS Overload Control
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Solution Overview
Problem
In wireless communication systems, system overload occurs when errors occur at control nodes or during system upgrades, leading to temporary overload of the Home Subscriber Server (HSS), which can cause registration failures and impact service availability.
Innovation Solution
A method and apparatus that reject request messages from terminals to the HSS for a predetermined period by configuring an MME-backoff time, allowing the system to manage overload by blocking transmissions during peak loads, thereby preventing system overload propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the HSS processes all location update request messages from terminals, then service availability is maintained, but system overload occurs during node errors or upgrades
Solution Approach 1:
The patent implements periodic action by introducing a backoff timer mechanism that periodically blocks request messages from terminals during overload conditions. The HSS sends a location update reject message with a backoff time parameter to the MME, which then rejects terminal requests for a predetermined period, creating a periodic interruption pattern that allows system recovery while maintaining reliability.
2Productivity
If the HSS blocks all request messages during overload, then system overload is controlled, but service availability deteriorates
Solution Approach 1:
The patent applies local quality by implementing selective blocking rather than universal blocking. The reject message includes a backoff time parameter that is locally configured based on the specific overload condition, allowing the MME to reject only terminal requests during the backoff period while maintaining normal processing of other messages. This localized control prevents complete service disruption.
3Reliability
If the MME forwards all TAU request messages to the HSS, then registration success rate is maintained, but network traffic increases during overload
Solution Approach 1:
The patent implements preliminary action by having the MME proactively reject terminal TAU requests before they reach the HSS during overload conditions. When the MME receives a backoff time parameter from the HSS, it preemptively rejects subsequent terminal requests for the specified duration, preventing these messages from consuming network resources and adding to traffic volume during critical periods.
Data Source
AI summary
The present invention relates to a method for controlling system overload in a wireless communication system. The method comprises: a first step in which a mobility management entity (MME) that has received a tracking region update request message from a first terminal transmits a location update request message to a home subscriber server (HSS); a second step in which, if the HSS has determined that a system overload has occurred, the HSS sets MME-backoff time for preventing the transmission of a request message to the HSS, and transmits a location update rejection message including said MME-backoff time to the MME; and a third step in which the MME drives a backoff timer corresponding to said MME-backoff time and rejects a TAU update request message from a terminal received prior to the completion of the driving of the backoff timer.