Network Slice PDU Session Transfer for Congestion and Maintenance
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Solution Overview
Problem
Existing 3GPP specifications do not provide comprehensive functionality for controlling the use of network slices in cellular communications systems, limiting operators' ability to optimize network performance and manage congestion or maintenance.
Innovation Solution
Implementing methods and systems that allow network functions to initiate and manage the transfer of Protocol Data Unit (PDU) sessions between network slices, including options for deregistering UEs, transferring PDU sessions, and applying Session and Service Continuity (SSC) logic, using extended message protocols and procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If network slicing is implemented to support multiple services with different service-level requirements, then network versatility and service capability are improved, but network complexity and control difficulty increase
Solution Approach 1:
The network is divided into multiple independent network slices, each serving specific services with dedicated resources and control mechanisms. This segmentation allows versatile service support while maintaining manageable complexity through modular isolation of different network functions and slices.
Solution Approach 2:
A Network Slice Admission Control Function (NSACF) is introduced as an intermediary component to manage and control network slice operations. This mediator handles admission control, monitoring, and coordination between different network slices, reducing overall network complexity by centralizing control functions.
2Reliability
If the number of registered UEs or PDU sessions per network slice is controlled to manage congestion, then network reliability and performance are improved, but network flexibility and ease of operation deteriorate
Solution Approach 1:
The NSACF continuously monitors network slice conditions including UE count, PDU session status, and resource utilization. Based on this feedback, the system dynamically adjusts admission control decisions to maintain reliability while adapting to changing network conditions, thereby preserving operational flexibility through automated response to real-time metrics.
3Productivity
If PDU sessions are transferred between network slices to alleviate congestion or enable maintenance, then network productivity and resource utilization are improved, but session continuity and user experience may be affected
Solution Approach 1:
The system performs preliminary actions by establishing PDU sessions in target network slices before transferring users from source slices. This make-before-break approach ensures session continuity by having the target slice ready to immediately take over, preventing service interruption during the transfer process and maintaining user experience while enabling productive slice management.
Data Source
AI summary
Systems and methods for controlling the use of a network slice in a core network of a cellular communications system are disclosed. In one embodiment, a method comprises, at a first Network Function (NF) in a core network of a cellular communications system, sending, to a second NF associated with a first network slice, a first message that initiates transfer of one or more Protocol Data Unit (PDU) sessions of a User Equipment (UE) from the first network slice to a second network slice. The method further comprises, at the second NF, receiving the first message from the first NF and sending, toward the UE, a session management message that causes the transfer of the one or more PDU sessions of the UE from the first network slice to the second network slice.