Mobility Management Procedure Selection for LTE Attach Without PDN
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high overhead costs associated with mobility management in LTE systems due to excessive message exchanges during attach procedures when a user equipment (UE) moves between networks without a Packet Data Network (PDN) connection.
Innovation Solution
A communication device and method that dynamically select either an attach procedure or a Tracking Area Update (TAU) procedure based on whether the target network supports an attach without PDN connection establishment, reducing unnecessary signaling exchanges by initiating a TAU procedure if supported and an attach procedure if not.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an attach procedure is performed when a UE moves from a first network to a second network without a PDN connection in the first network, then the UE can establish mobility management with the second network, but the overhead of message exchanges between the MME and the UE increases significantly
Solution Approach 1:
The patent applies preliminary action by checking whether the UE has a PDN connection in the first network before initiating the attach procedure. If the UE already has a PDN connection, the network can prepare and maintain the mobility management context in advance, avoiding the need for complete re-establishment and reducing signaling overhead when the UE moves to the second network.
Solution Approach 2:
The patent implements dynamics by dynamically selecting between different mobility management procedures based on the UE's PDN connection status. The system adapts its behavior: using full attach procedure when no PDN connection exists, and using simplified procedures when PDN connection is established, thereby optimizing the balance between reliability and signaling overhead according to real-time conditions.
2Reliability
If an attach procedure is always performed during network transitions without PDN connection, then mobility management is ensured, but the system capacity and throughput of the LTE system are reduced due to excessive overhead
Solution Approach 1:
The patent applies partial action by performing only the necessary mobility management functions rather than always executing the complete attach procedure. When the UE has an existing PDN connection, the system performs partial updates (such as tracking area updates) that maintain mobility management while consuming fewer resources, thereby preserving system throughput while ensuring reliability.
Solution Approach 2:
The patent changes the parameter of mobility management procedure selection based on the PDN connection status. By monitoring whether the UE has an active PDN connection, the system dynamically adjusts the mobility management approach, switching between full attach and simplified procedures, which reduces overall signaling overhead and improves system capacity and throughput.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A communication device for handling mobility management comprises a storage unit for storing instructions and a processing circuit coupled to the storage unit. The processing circuit is configured to execute the instructions stored in the storage unit. The instructions comprise attaching to a first network and not having an active Packet Data Network (PDN) connection with the first network; selecting a second network after attaching to the first network; initiating an attach procedure to the second network, if the second network does not support an attach without the PDN connection establishment; and initiating a tracking area update (TAU) procedure to the second network, if the second network supports the attach without the PDN connection establishment.