Session Management Back-off Timer for PDN Connection Re-activation
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Solution Overview
Problem
In wireless communication networks, particularly in 3GPP LTE systems, the network may reject bearer resource allocation or modification requests due to insufficient resources, leading to congestion and preventing re-establishment of PDN connections during session or mobility management back-off timers, which hinders network re-activation and re-attachment procedures.
Innovation Solution
A method where user equipment (UE) receives a session management back-off time value from the Mobility Management Entity (MME) upon rejection, starts a timer, and stops it upon receiving a deactivate bearer context request, allowing for subsequent packet data network connectivity requests after timer cessation, ensuring efficient resource management and re-activation of PDN connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the network provides back-off timers to control further signaling from the UE during congestion, then network congestion is alleviated, but the UE cannot re-establish PDN connections during the back-off timer period even when resources become available
Solution Approach 1:
The patent makes the back-off timer dynamic by allowing the UE to stop the timer when receiving a deactivate bearer context request message with cause code indicating reactivation requested. This transforms the static back-off mechanism into a dynamic one that can adapt to network conditions and resource availability, resolving the contradiction between congestion control and connection re-establishment capability.
Solution Approach 2:
The patent implements feedback by having the network send a deactivate bearer context request message with a specific cause code to the UE. The UE monitors this feedback signal and responds by stopping the back-off timer and initiating PDN connection re-establishment, creating a closed-loop control system that balances congestion management with service restoration.
2Speed
If the UE continuously requests bearer resource allocation during congestion, then connection establishment speed is improved, but network congestion worsens
Solution Approach 1:
The patent implements periodic action through the back-off timer mechanism, where the UE waits for a specified time period before attempting further bearer resource allocation requests. This periodic waiting pattern prevents continuous signaling during congestion while still allowing the UE to retry connections when the timer expires or is stopped, balancing connection speed with congestion control.
Data Source
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AI summary
The technical features of this document provide a method and wireless apparatus for processing data associated with bearer resources, session management, and/or mobility management. The method comprises transmitting a packet data network connectivity request message to a mobility management entity (MME) for establishing a packet data network connection; receiving a session management back-off time value from the MME when a request of bearer resource modification or bearer resource allocation for the established packet data network connection is rejected by the MME; starting a session management back-off timer according to the session management back-off time value, the session management back-off timer being associated with the established packet data network connection; and receiving a deactivate bearer context request message, from the MME, including a cause code indicating that reactivation is requested and stopping the session management back-off timer if the session management back-off timer is running.