5G PDU Session Management via AMF-SMF Coordination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The 5G cellular wireless communication system faces challenges in efficiently managing UP connection resources, particularly in scenarios where terminals transition between CM-IDLE and CM-CONNECTED states, leading to increased signaling load and resource inefficiencies due to the need for separate management of mobility and session functions.
Innovation Solution
A method is proposed where the session management function (SMF) and access and mobility management function (AMF) coordinate to determine the maintenance or release of user plane functions (UPFs) based on the NAS signaling connection state, using an indication for synchronization/asynchronization with the NAS signaling connection as an attribute of the PDU session, allowing for optimized UP connection management and reduced signaling load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate management of mobility and session functions is implemented, then network functionality and control are improved, but signaling load and system complexity increase
Solution Approach 1:
The patent segments the core network functions by separating the Access and Mobility Management Function (AMF) from the Session Management Function (SMF). The AMF handles mobility management and NAS signaling, while the SMF handles session management and UP connection control. This segmentation allows each function to be optimized independently, improving network control reliability while managing complexity through functional separation.
Solution Approach 2:
The patent introduces the AMF as an intermediary between the terminal and the SMF. The AMF receives NAS signaling from the terminal, determines the NAS connection state, and coordinates with the SMF to manage UP connections. This intermediary role reduces direct signaling between terminals and session management entities, lowering overall signaling load while maintaining reliable control.
2Speed
If UP connections are maintained during CM-IDLE state, then data transmission speed is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent implements dynamic UP connection management where the state of UP connections is synchronized with the NAS signaling connection state. When the terminal transitions to CM-IDLE, the AMF determines the NAS connection state and notifies the SMF, which then dynamically adjusts UP connection maintenance decisions. This allows the system to optimize between speed and resource efficiency based on actual connection states rather than using static rules.
Solution Approach 2:
The patent changes the parameter of UP connection maintenance from a static configuration to a dynamic state-dependent parameter. The SMF uses the indication for synchronization with NAS signaling connection state to determine whether to maintain or release UP connections. This parameter change enables flexible adaptation to different terminal states, improving both transmission speed when needed and resource efficiency when terminals are idle.
3Productivity
If UP connection resources are released during state transitions, then resource efficiency is improved, but data transmission latency increases
Solution Approach 1:
The patent implements preliminary action by maintaining UP connections in advance when the NAS signaling connection state indicates potential future data transmission needs. The SMF, upon receiving notification from the AMF about NAS connection state changes, can proactively maintain UP connections rather than releasing them immediately. This preliminary maintenance of connections reduces latency when data transmission is subsequently needed while still allowing resource release when connections are definitively not needed.
Data Source
AI summary
A communication method and system converges a 5G communication system for supporting higher data rates beyond a 4G system with an IoT technology. The system and method may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Embodiments provide a scheme for efficiently operating an UP connection of a session in case where a terminal has a plurality of sessions in a mobile communication system, such as a 5G system, having a network structure in which an AMF for mobility management and an SMF for session management are separated from each other. A terminal (UE) can optimize a non-access stratum (NAS) signaling message, and can perform data transmission/reception with low latency.