Paging Cause Conveyance for 5G Inactive UEs

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Solution Overview

Problem

Current proposals for the Third Generation Partnership Project (3GPP) do not provide a method to convey the Paging Cause to a user equipment (UE) in a Radio Resource Control Inactive (RRC_INACTIVE) state, which is essential for determining the appropriate paging strategy.

Innovation Solution

The proposed solution involves carrying the Paging Cause in the GTP-U subheader of every data packet on the N3 and N9 interfaces, utilizing the Differentiated Service Code Point (DSCP) value from the IP header, and including it in the CN tunnel header, allowing the NG-RAN to enforce specific paging policies when the UE is in an RRC_INACTIVE state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the Paging Cause is conveyed to UE in RRC_IDLE state using existing proposals, then the UE can determine appropriate paging response strategy, but there is no mechanism to convey Paging Cause to UE in RRC_INACTIVE state

Engineering Contradiction:

ImprovePaging Cause informationVSAvoidPaging strategy applicability

Core Design Contradiction:

Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent extends the existing Paging Cause mechanism (originally designed for RRC_IDLE state) to also function for RRC_INACTIVE state UEs. By making the paging message format and processing logic universal across both RRC_IDLE and RRC_INACTIVE states, the system enables Paging Cause information to be effectively conveyed to both types of UEs using the same infrastructure, thus resolving the information loss for inactive UEs while maintaining system versatility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces the AMF (Access Management Function) as an intermediary that determines and includes the Paging Cause in the paging message sent to the RAN. This intermediary ensures that the Paging Cause information is properly generated and transmitted through the network infrastructure to reach RRC_INACTIVE UEs, bridging the gap between the core network's paging decision and the inactive UE's reception capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If Paging Cause is included in paging message for all UEs, then traffic prioritization is improved, but message complexity increases

Engineering Contradiction:

ImprovePaging strategy efficiencyVSAvoidPaging message structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent utilizes the existing Paging Cause parameter (with predefined values like 'IMS voice', 'IMS SMS', 'IMS other', or 'other') that was originally designed for RRC_IDLE UEs. By reusing this established parameter without modifying its definition or structure, the system achieves traffic prioritization for RRC_INACTIVE UEs while avoiding any increase in message complexity. The parameter's meaning and format remain unchanged, ensuring backward compatibility and simplicity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11985626B2Paging cause determination for an inactive device in a 5G system

Publication Date: 2024.05.14 APPLE INC

AI summary

An apparatus of a next generation NodeB (gNB) comprises one or more baseband processors to receive a downlink Protocol Data Unit (DL PDU) from User Plane Function for a user equipment (UE) in a Radio Resource Control Inactive (RRC_INACTIVE) state, wherein the DL PDU includes a Paging Cause to indicate to the UE a reason for the page, and to send the Paging Cause in a paging message to the UE. The apparatus can include a memory to store the paging message.