AMF Idle-Mode Mobility Using Shared Tracking Area Identities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 5G networks, particularly in enterprise private networks, frequent UE context transfers during idle mode mobility lead to significant signaling and processing overheads due to small cell sizes and AMF footprints, which are unnecessary when the UE remains in idle mode for short periods.
Innovation Solution
Provisioning multiple AMFs with the same tracking area identity (TAI) to avoid unnecessary UE context transfers by ensuring that UE context remains anchored at the original AMF even when the user equipment moves between cells, thereby eliminating mobility registration procedures in idle mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple AMFs are deployed with small cell sizes and AMF footprints to improve network flexibility and coverage, then network adaptability and service capability are enhanced, but frequent UE context transfers occur during idle mode mobility leading to increased signaling overhead and processing load
Solution Approach 1:
The patent segments the tracking area management by introducing the concept of multiple TAI values associated with a single AMF. Instead of having a one-to-one mapping between TAI and AMF, the system allows one AMF to serve multiple TAIs, thereby reducing the frequency of context transfers while maintaining network flexibility through proper segmentation of tracking areas.
Solution Approach 2:
The patent applies universality by enabling a single AMF to handle multiple tracking area identities (TAIs). This multi-functionality allows the AMF to serve multiple tracking areas without requiring context transfer, thereby reducing signaling overhead while maintaining the ability to support diverse network configurations and mobility scenarios.
2Reliability
If UE context is transferred frequently between AMFs during idle mode mobility, then mobility management accuracy is maintained, but processing load and resource consumption increase significantly
Solution Approach 1:
The patent implements preliminary action by pre-configuring multiple TAI values at the AMF before mobility events occur. When a UE moves between tracking areas, the AMF is already prepared to handle the new TAI without requiring context transfer, thereby maintaining mobility management accuracy while avoiding the processing overhead of frequent context transfers.
Solution Approach 2:
The patent changes the parameter mapping relationship between TAI and AMF from a one-to-one mapping to a one-to-many mapping. This parameter change allows the UE to move between multiple tracking areas under the same AMF without triggering context transfers, thereby maintaining mobility management accuracy while significantly improving processing efficiency.
3Reliability
If traditional mobility registration procedures are executed during idle mode mobility, then network control and security are maintained, but unnecessary signaling overhead occurs when UE remains in idle mode for short periods
Solution Approach 1:
The patent applies local quality by allowing different mobility management behaviors for different tracking areas. Within a set of tracking areas associated with the same AMF, the system implements a simplified mobility procedure that does not require full registration, while maintaining proper network control. This local optimization reduces signaling overhead for short-duration idle mode mobility while preserving security and control for longer-term mobility events.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method is provided for avoiding context transfers by a first Access and Mobility Management Function (AMF) connected to a first gNB to a second AMF when a user equipment (UE) in idle mode moves from the first gNB to a second gNB. The method may include provisioning the first AMF and the second AMF with the same tracking area identity (TAI), the first AMF and the second AMF being connected to a respective enterprise gNB. The method may also include configuring the 5G packet core network comprising a session management function (SMF) in communications with the first AMF and the second AMF, to avoid transferring a UE context from the first AMF to the second AMF when the user equipment (UE) in the idle mode moves from a first AMF to the second AMF. The UE context remains with the first AMF.