Random Access Resource Switching for Coverage-Enhanced Terminals

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Solution Overview

Problem

The random access procedure in future radio communication systems, such as NR, is indefinite, leading to reduced communication throughput unless coverage enhancement is achieved.

Innovation Solution

A terminal that receives information related to a first random access procedure and uses a first random access resource, and a second random access resource different from the first, for a second random access procedure without message 1 repetition, enhancing coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If random access procedure uses message 1 repetition for coverage enhancement, then coverage is improved, but device complexity increases due to indefinite procedure definition

Engineering Contradiction:

Improvecoverage areaVSAvoidrandom access procedure complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The random access procedure is segmented into two distinct types: first random access procedure with message 1 repetition for coverage enhancement, and second random access procedure without repetition for normal operation. This segmentation allows the system to apply complexity only where needed (coverage enhancement scenarios) while maintaining simple operation for standard cases.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The terminal dynamically selects between first and second random access resources based on received information indicating which procedure type should be used. This dynamic selection mechanism allows the system to adapt to varying coverage requirements without permanently increasing complexity for all operations.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If random access procedure is made indefinite, then flexibility is improved, but communication throughput deteriorates

Engineering Contradiction:

Improveprocedure flexibilityVSAvoidcommunication throughput

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The system changes the parameter of random access resource selection based on received information. By receiving indication information that specifies whether to use first or second random access resources, the terminal can adapt the procedure type to match current coverage conditions, maintaining both flexibility and efficient throughput by avoiding unnecessary complexity in normal operations.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If message 1 repetition is used for coverage enhancement, then reliability is improved, but loss of time increases due to repeated transmissions

Engineering Contradiction:

Improverandom access reliabilityVSAvoidaccess time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Message 1 repetition is applied locally only to the first random access procedure when coverage enhancement is needed, while the second random access procedure maintains single transmission for faster access. This localized application of repetition ensures reliability improvement is concentrated where coverage problems exist, without unnecessarily extending access time for all random access operations.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260006650A1Terminal, radio communication method, and base station

Publication Date: 2026.01.01 NTT DOCOMO INC

AI summary

A terminal according to an aspect of the present disclosure includes a receiving section that receives information related to first random access procedure including a repetition of a message 1, and a control section that, based on the information, uses, for the first random access procedure, a first random access resource and uses, for second random access procedure not including the repetition of the message 1, a second random access resource different from the first random access resource. According to an aspect of the present disclosure, it is possible to enhance coverage in random access procedure.