Terminal Resource Control for Cross-RAT Collision Avoidance

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Solution Overview

Problem

Existing wireless communication systems face challenges in sharing resources between device-to-device direct communications that use different Radio Access Technologies (RATs), as signals of one RAT are distinct from those of another, making it difficult to detect and avoid collisions.

Innovation Solution

A terminal is equipped with a communication unit that operates in overlapping resource pools of multiple RATs, and a control unit that excludes resources in one RAT that collide with those of another RAT in the time domain, enabling resource sharing between different RATs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If terminals autonomously determine resources and perform collision-avoiding operations by decoding signals, then resource utilization efficiency improves, but resource sharing between different RATs deteriorates due to signal incompatibility

Engineering Contradiction:
Improveresource utilization efficiencyVSAvoidresource sharing between different RATs
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a base station as an intermediary to allocate resources for D2D communication. The base station receives buffer status reports from terminals, determines appropriate resource pools (first RAT or second RAT), and allocates resources accordingly. This intermediary approach enables resource sharing between different RATs by centralizing the allocation decision-making process, resolving the signal incompatibility issue that prevents autonomous collision avoidance between different RATs.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where terminals report buffer status to the base station, and the base station uses this feedback to make informed resource allocation decisions. The base station determines whether to allocate resources in the first RAT resource pool or second RAT resource pool based on the buffer status feedback, enabling dynamic and efficient resource sharing across different RATs while maintaining autonomous transmission capabilities.

Inventive Principle:
Principle #23Feedback

2Reliability

If separate resource pools are used for different RATs, then collision avoidance between RATs improves, but resource sharing and utilization efficiency deteriorates

Engineering Contradiction:
Improvecollision avoidance between RATsVSAvoidresource sharing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic resource pool selection where the base station can flexibly allocate resources to either the first RAT resource pool or the second RAT resource pool based on real-time buffer status feedback. This dynamic allocation allows the system to adapt to changing traffic conditions and utilize the most appropriate resource pool for each transmission, achieving both collision avoidance and efficient resource sharing between different RATs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the allocation parameter from fixed separate resource pools to dynamic selection between overlapping resource pools. By modifying the resource allocation parameters based on buffer status reports, the system can switch between using the first RAT resource pool and the second RAT resource pool, enabling efficient resource sharing while maintaining collision avoidance through base station-controlled allocation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4618681A1Terminal and communication method
Publication Date: 2025.09.17 NTT DOCOMO INC
  • EP4618681A1 patent drawingFigure 1
  • EP4618681A1 patent drawingFigure 2~4
  • EP4618681A1 patent drawingFigure 5

AI summary

A terminal includes: a communication unit configured to perform transmission and reception in a resource pool of a first RAT (Radio Access Technology) and a resource pool of a second RAT, the resource pools overlapping with each other; and a control unit configured to control communications in the resource pool of the first RAT. The control unit excludes, from candidates used for transmissions in the first RAT, at least several resources among resources in the resource pool of the first RAT that collide with transmissions in the resource pool of the second RAT in a time domain.