UE Idle-State Paging Across 3GPP and Non-3GPP Access
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Solution Overview
Problem
The challenge in 5G networks is that UEs in CM-IDLE state over non-3GPP access become unreachable when they move out of coverage, preventing the activation of the user plane for down-link data or signaling, even if they remain within non-3GPP coverage.
Innovation Solution
Implementing methods such as AMF-initiated paging or handover procedures to trigger Service Requests over preferred access types, including indications for 3GPP or non-3GPP access, ensuring data delivery even when UEs transition to CM-IDLE state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If UE enters CM-IDLE state over non-3GPP access to save energy and reduce network resources, then energy consumption and network resource usage are reduced, but the UE becomes unreachable when moving out of coverage, preventing data delivery
Solution Approach 1:
The patent implements dynamic access type indication in paging messages, allowing the network to flexibly indicate whether the UE should perform service request over 3GPP or non-3GPP access based on current coverage conditions. This dynamic adaptation resolves the contradiction by enabling the UE to switch access types dynamically rather than being static in CM-IDLE state
Solution Approach 2:
The patent introduces an intermediary indication mechanism in the paging message that mediates between the network's desire to reach the UE and the UE's energy-saving idle state. This intermediary signal guides the UE's behavior without requiring continuous monitoring, thus maintaining reachability while preserving energy benefits
2Duration of action of moving object
If UE remains in CM-IDLE state to maintain battery life, then battery life is extended, but user plane activation and data delivery are prevented when UE moves out of non-3GPP coverage
Solution Approach 1:
The patent applies preliminary action by providing the access type indication in advance within the paging message, before the UE needs to decide whether to activate user plane. This allows the UE to prepare the appropriate service request without prolonged idle state, thus extending battery life while maintaining data delivery capability
Solution Approach 2:
The patent changes the parameter of access type selection by encoding it in the paging message. This parameter change enables the UE to transition from passive idle state to active service request with the correct access type, resolving the contradiction between battery life extension and data delivery capability
3Reliability
If network implements paging and service request procedures to ensure UE reachability, then UE reachability is improved, but network signaling overhead and complexity increase
Solution Approach 1:
The patent segments the service request procedure by including access type indication as a separate element in the paging message. This segmentation allows the network to provide targeted guidance to the UE, improving reachability while reducing the complexity of the overall signaling procedure by avoiding unnecessary trial-and-error approaches
4Reliability
If UE performs service request over 3GPP access when in CM-IDLE over non-3GPP access, then data delivery is ensured, but network resource usage and energy consumption increase
Solution Approach 1:
The patent applies local quality by making the access type selection specific to each paging scenario through the access type indication. This allows the UE to choose the most energy-efficient access type (non-3GPP when available, 3GPP when necessary) on a case-by-case basis, rather than always defaulting to 3GPP, thus reducing energy consumption while ensuring data delivery
Data Source
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AI summary
The embodiments herein relate to methods and functions for handling a user equipment, UE, that is in an idle state with respect to at least one access type e.g., 3GPP access or non-3GPP access. According to an embodiment, an Access and mobility Management Function, AMF, receives from a Session Management Function, SMF, a request to establish User Plane, UP, for a UE's PDU session, wherein the request comprises information indicating a preferred access type. According to another embodiment, an SMF receives from a User Plane Function, UPF, a notification that the UPF is buffering downlink data for a UE's PDU sessions; and in response to the notification sent by the UPF, the SMF sends to an AMF, serving the UE, a request to establish User Plane, UP, for the PDU session, wherein the request comprises information indicating a preferred access type. According to a further embodiment, a UE receives a page message, wherein the page message is configured to trigger the UE to make a Service Request, SR, over non-3GPP access; and the UE, in response to receiving the page message, performs a Service Request procedure over non-3GPP access if non-3GPP access is available.