Wireless Timer Control for Idle Mode Signaling Reduction
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Solution Overview
Problem
The existing 3GPP LTE system faces challenges in efficiently managing timers associated with idle mode signalling reduction (ISR) when user equipment (UE) moves between different network types, leading to potential loss of UE context and network resource inefficiencies due to incorrect timer settings and network congestion.
Innovation Solution
A method is introduced to control timers such as the periodic tracking area update (P-TAU) timer, mobility management backoff (MM-BO) timer, and deactivate ISR timer, ensuring proper UE location registration and context maintenance by starting and managing these timers based on specific network conditions and messages, particularly when the UE moves between LTE and 2G/3G networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the UE uses idle mode signalling reduction (ISR) to remain registered in both 2G/3G routing area and LTE tracking area, then mobility signalling is reduced and battery life is improved, but timer management becomes complex and UE context may be lost when moving between network types
Solution Approach 1:
The patent implements dynamic timer management where the deactivate ISR timer is selectively started based on network type and timer state. When the P-TAU timer expires and the UE is in 2G/3G network with MM-BO timer running, the deactivate ISR timer is started to properly manage ISR state. This dynamic adaptation resolves the contradiction by making timer management context-dependent rather than static, reducing complexity while maintaining energy efficiency.
Solution Approach 2:
The patent introduces feedback mechanisms through timer expiration events and network type detection. When P-TAU timer expires or MM-BO timer state changes, the system feedback triggers appropriate timer actions. This feedback loop ensures proper UE context maintenance during mobility between LTE and 2G/3G networks, preventing context loss while managing ISR efficiently, thus reducing complexity without sacrificing battery life benefits.
2Reliability
If the UE frequently updates its location between LTE and 2G/3G networks, then network connectivity is maintained, but network congestion increases and signaling overhead increases
Solution Approach 1:
The patent applies preliminary action by starting the deactivate ISR timer in advance when specific conditions are met (P-TAU expiration combined with MM-BO timer running state in 2G/3G network). This proactive timer management prepares the system for potential ISR deactivation before actual mobility events occur, allowing the UE to maintain connectivity through proper context management while avoiding unnecessary location update signaling, thus reducing signaling overhead while preserving reliability.
3Productivity
If the UE maintains accurate UE context during mobility between network types, then network resource efficiency is improved, but timer control complexity increases
Solution Approach 1:
The patent implements local quality by applying different timer management strategies based on local network conditions. Specifically, the deactivate ISR timer is started only when the UE is in 2G/3G network with specific timer states (P-TAU expired, MM-BO running), rather than uniformly across all scenarios. This localized approach maintains accurate UE context where needed while avoiding unnecessary timer complexity in other scenarios, achieving network resource efficiency without excessive complexity.
Data Source
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AI summary
The technical features of this document provide a method and wireless apparatus for controlling a number of timers associated with ISR function. The method is applicable to a user equipment moving between different networks, i.e., different radio access networks such as 2G/3G and LTE. The method is associated with a deactivate timer which can be initiated following a periodic tracking area updating timer. The method comprises starting the deactivate ISR timer when the periodic tracking area updating timer expires and the mobility management back-off timer is running while the UE is in the coverage of LTE.