Core Node Congestion Control via APN-Specific Back-Off Timers
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Solution Overview
Problem
Current congestion control methods in mobile core networks fail to effectively reduce the processing load on control nodes like MMEs, as radio terminals can transmit NAS messages with different APNs before the back-off timer expires, leading to increased message transmission and processing load during congestion states.
Innovation Solution
A core node and radio terminal system that detects congestion states, transmits a reject message including multiple APNs to the radio terminal, preventing it from sending NAS messages until the congestion is resolved, thereby reducing the number of messages and data transmitted to the core node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the MME transmits a reject message with a single back-off timer value, then the processing load is reduced for the specific rejected NAS message, but the radio terminal can still transmit new NAS messages with different APNs before the timer expires, causing the MME to remain in congestion state
Solution Approach 1:
The invention segments the congestion control mechanism by introducing multiple back-off timer values corresponding to different APNs. Instead of a single aggregate back-off timer, each rejected NAS message associated with a specific APN now has its own dedicated back-off timer value, allowing granular control over message transmission for each APN while maintaining overall congestion management.
Solution Approach 2:
The invention changes the parameter structure of the reject message by including multiple back-off timer values instead of a single value. Each back-off timer value is associated with a specific APN, transforming the congestion control from a coarse-grained approach to a fine-grained approach that can differentiate between various APN-based traffic streams.
2Adaptability or versatility
If the radio terminal transmits NAS messages with different APNs before the back-off timer expires, then the terminal maintains communication flexibility, but the MME cannot suppress transmission of NAS messages, leading to increased message transmission and processing load
Solution Approach 1:
The invention segments the back-off timer control by creating separate timer values for different APNs. This allows the radio terminal to maintain communication flexibility with APNs that have not been rejected while suppressing transmissions only for APNs associated with rejected messages, achieving selective message suppression based on APN-specific congestion states.
Solution Approach 2:
The invention applies local quality control by making the back-off timer APN-specific rather than global. Each APN can have its own back-off timer value, allowing the system to apply different congestion control policies to different APNs locally, thereby maintaining communication flexibility for non-congested APNs while controlling load for congested ones.
3Productivity
If the MME rejects all NAS messages during congestion, then the processing load is reduced, but the radio terminal cannot transmit any messages including those for non-congested services, reducing service availability
Solution Approach 1:
The invention segments the rejection control by APN, allowing the MME to reject messages for specific congested APNs while permitting messages for other non-congested APNs. This segmentation enables selective service availability maintenance, where services corresponding to non-congested APNs remain accessible even during overall network congestion.
Solution Approach 2:
The invention changes the reject message parameters to include multiple APN-specific back-off timer values instead of a single global timer. This parameter change enables the radio terminal to distinguish between congested and non-congested APNs, allowing it to continue transmitting messages for non-congested services while suppressing transmissions for congested services.
Data Source
AI summary
The present disclosure aims to provide a core node capable of reducing the number of messages or an amount of data to be transmitted to the core node. A core node (10) according to the present disclosure includes: a congestion state detector (11) configured to detect a congestion state of an own apparatus; a communication unit (13) configured to receive a NAS request message that has specified an APN from a radio terminal (20); and a controller (12) configured to determine that processing regarding the NAS request message will not be executed while the congestion state of the own apparatus is being detected. The communication unit (13) transmits a reject message including a plurality of APNs that can be specified by the radio terminal (20) to the radio terminal (20) when it is determined in the controller (12) that the processing regarding the NAS request message will not be executed.