PDU Session Handling in LTE to 5G Inter-System Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inter-system mobility between LTE and NR/5G systems poses challenges for seamless service continuity in wireless communication systems, particularly in handling PDU sessions during network transitions.
Innovation Solution
A communication device and method that manage PDU sessions by connecting to NR/5G and LTE networks, performing tracking area updates, and maintaining PDU Session IDs to ensure continuous service across network transitions, allowing for seamless mobility between the two systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs a tracking area update procedure when moving between LTE and NR/5G systems, then service continuity can be maintained, but the complexity of inter-system mobility management increases
Solution Approach 1:
The network stores the PDU session ID and session context information in advance before the UE moves between systems. When the UE performs tracking area update, the network can quickly retrieve the stored session information and restore the PDU session without requiring complex real-time negotiation, thus maintaining service continuity while reducing mobility management complexity.
Solution Approach 2:
The core network acts as an intermediary that maintains PDU session context information during inter-system mobility. The network entity stores and manages the PDU session ID and session parameters, mediating between the UE and the access networks (LTE/NR) to ensure seamless session continuity without burdening the UE with complex mobility management logic.
2Reliability
If the PDU session context is maintained during network switching, then service continuity is improved, but the network resource consumption increases
Solution Approach 1:
The network maintains PDU session context information selectively at specific network entities (such as the core network or access network controllers) rather than throughout the entire network. This localized storage approach ensures service continuity while minimizing overall network resource consumption by only preserving essential session parameters where needed.
Solution Approach 2:
The network employs a strategy of discarding detailed PDU session context when the UE is inactive or in a low-power state, and recovering only the essential PDU session ID and minimal parameters when the UE becomes active again. This approach balances service continuity with network resource efficiency by maintaining only necessary information during idle periods.
Data Source
AI summary
A communication device for handling mobility between a new radio (NR)/fifth generation (5G) network and a long-term evolution (LTE) network comprises a storage device for storing instructions and a processing circuit coupled to the storage device. The processing circuit is configured to execute the instructions stored in the storage device. The instructions comprise connecting to the NR/5G network; communicating a Protocol Data Unit (PDU) Session identity/identifier (ID) identifying a PDU Session with the NR/5G network; communicating data of the PDU Session with the NR/5G network; disconnecting the NR/5G network, connect to the LTE network and performing a tracking area update (TAU) procedure with the LTE network; disconnecting the LTE network and connect to the NR/5G network, after performing the TAU procedure; and communicating the PDU Session ID identifying the PDU Session with the NR/5G network, when disconnecting the LTE network and connecting to the NR/5G network.