Cell Selection Logic for RedCap and eRedCap Access Restrictions

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Solution Overview

Problem

Existing technologies face challenges in implementing appropriate cell access restrictions for RedCap UEs and eRedCap UEs when they are present in mixed states, as specified in 3GPP Release-17 and 18.

Innovation Solution

A terminal equipped with a reception unit to receive broadcast information on access restrictions for both RedCap and eRedCap UEs, and a control unit to perform cell selection based on these restrictions, ignoring or assuming access restrictions for RedCap UEs when indicated for eRedCap UEs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If access restriction for RedCap UE is indicated in broadcast information, then cell access control for RedCap UE is achieved, but when eRedCap UE is also present, the access restriction cannot be appropriately differentiated between the two terminal types

Engineering Contradiction:

Improvecell access control accuracyVSAvoidsupport for multiple terminal types

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the access restriction indication by introducing terminal type-specific fields: one set of indication bits for RedCap UE and another set for eRedCap UE. This allows independent control and differentiation of access restrictions for each terminal type, resolving the contradiction between accurate access control and multi-terminal-type support.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing differentiated access restriction parameters tailored to each terminal type's specific capabilities. RedCap UE receives access restriction settings appropriate for its capability level, while eRedCap UE receives different settings suited to its enhanced capabilities, allowing optimized access control for each segment.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a single access restriction parameter is used for both RedCap UE and eRedCap UE, then broadcast information structure is simple, but appropriate access control for each terminal type cannot be achieved

Engineering Contradiction:

Improvebroadcast information structureVSAvoidaccess restriction accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent divides the access restriction indication into separate segments for RedCap UE and eRedCap UE, with dedicated indication bits and parameters for each terminal type. This segmentation maintains clear structure while enabling precise access control for each category.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic flexibility by allowing the network to independently configure access restriction parameters for different terminal types based on current network conditions and terminal capabilities, rather than using fixed single-parameter restrictions.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4668871A1Terminal and wireless communication method

Publication Date: 2025.12.24 NTT DOCOMO INC

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AI summary

A terminal receives broadcast information including access restrictions to a cell for a first type of terminal of which a capability is reduced compared to a capability of a normal terminal, and a second type of terminal of which a capability is further reduced compared to the capability of the first type of terminal; and the terminal performs cell selection based on content of the access restrictions. The terminal ignores the access restriction for the first type of terminal, when the access restriction for the second type of terminal is indicated using the broadcast information.