Multi-SIM UE Busy Indication for Priority-Based Page Handling

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Solution Overview

Problem

User equipment (UE) with multiple SIMs faces challenges in handling pages from one network while prioritizing operations with another network, particularly in managing busy indications effectively when in an RRC inactive state.

Innovation Solution

The UE sends a non-access stratum (NAS) busy indication to the network using various signaling messages such as RRC Resume Request, RRC Resume Complete, RRC Setup Complete, or a newly defined Signaling Radio Bearer (SRB) message, depending on its state and priority of operations, to indicate its inability to handle pages from the first network when in an RRC inactive state with the second network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE monitors the second network for pages while in RRC inactive state, then the UE can detect incoming pages from the second network, but the UE cannot handle pages from the first network when operations with the second network have higher priority

Engineering Contradiction:

Improvepage handling capabilityVSAvoidmulti-network operation flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The UE dynamically adjusts its page handling behavior based on the priority of ongoing operations with the second network. When high-priority operations are detected, the UE transitions from a state where it can handle pages to a state where it sends BUSY indications, allowing flexible adaptation to changing network conditions and operational priorities

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The BUSY indication message serves as an intermediary mechanism between the UE and the first network. Instead of directly rejecting pages or attempting to handle them simultaneously, the UE uses the BUSY indication to communicate its unavailable state to the first network, resolving the conflict between monitoring the second network and handling pages from the first network

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the UE sends BUSY indication to the first network, then the UE can prioritize operations with the second network, but additional signaling overhead is introduced

Engineering Contradiction:

Improveoperation priority managementVSAvoidsignaling messages

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The BUSY indication is merged with existing RRC signaling messages such as RRC Resume Request or RRC Setup Complete. By combining the BUSY indication functionality with already-necessary signaling messages, the patent avoids introducing separate dedicated signaling overhead while still achieving priority management

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20240080804A1BUSY Indication Transmitted by a Multi-SIM User Equipment

Publication Date: 2024.03.07 APPLE INC

AI summary

A multi-universal subscriber identity module (MUSIM) user equipment (UE) is configured to operate in an Radio Resource Control (RRC) inactive state with a first network associated with the first SIM, operate in an RRC connected state with a second network associated with the second SIM, receive a page from the first network, determine that a priority of at least one operation being performed between the UE and the second network is higher than a priority of the page and send a BUSY indication to the first network in response to the page.