NR-U Reservation Signal Color Coding for Tight Frequency Reuse

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently sharing unlicensed spectrum among multiple network operating entities, with asynchronous sharing leading to lower spectral efficiency and network capacity, while coordinated priority-based sharing requires extensive coordination efforts.

Innovation Solution

Implementing tight frequency reuse color coding techniques, where each operator is assigned a unique waveform sequence for spectrum reservations, allowing energy detection-based LBT to determine spectrum access and enable synchronized communications among operators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If asynchronous spectrum sharing is used among multiple network operating entities, then spectrum access flexibility is improved, but spectral efficiency deteriorates

Engineering Contradiction:
Improvespectrum access flexibilityVSAvoidspectral efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies color coding to reservation signals where each network operating entity is assigned a unique color (waveform sequence). This allows receiving entities to quickly identify and filter reservations from different operators, enabling flexible asynchronous access while maintaining high spectral efficiency through efficient spectrum utilization and reduced collisions

Inventive Principle:
Principle #32Color changes

2Productivity

If coordinated priority-based spectrum sharing is implemented, then spectral efficiency is improved, but coordination complexity increases

Engineering Contradiction:
Improvespectral efficiencyVSAvoidcoordination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent enables each network operating entity to independently perform clear channel assessment and make transmission decisions based on detecting color-coded reservation signals from other entities. This self-service mechanism achieves coordinated spectrum sharing and high spectral efficiency without requiring complex centralized coordination infrastructure

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

By assigning unique color codes (waveform sequences) to each operator's reservation signals, the system enables automatic identification and filtering of reservations. This simplifies the coordination mechanism while maintaining high spectral efficiency through efficient spectrum utilization and collision avoidance

Inventive Principle:
Principle #32Color changes

3Reliability

If traditional LBT procedures are used in unlicensed spectrum, then collision avoidance is improved, but network capacity deteriorates

Engineering Contradiction:
Improvecollision avoidanceVSAvoidnetwork capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent enhances traditional LBT by incorporating color-coded waveform sequences in reservation signals. This allows entities to identify and prioritize reservations from different operators, enabling more aggressive spectrum access strategies that increase network capacity while maintaining collision avoidance through the underlying LBT mechanism

Inventive Principle:
Principle #32Color changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances spectral efficiency and network capacity by allowing better frequency reuse with reduced coordination complexity, enabling flexible spectrum sharing and lower interference.

Implementation Method 1

allowing energy detection-based LBT to determine spectrum access

Methodology Applied
Scientific EffectEnergy detection:

Data Source

PatentEP3871437B1Tight frequency reuse coloring for new radio-unlicensed (NR-u)
Publication Date: 2026.02.25 QUALCOMM INC
  • EP3871437B1 patent drawingFigure 1
  • EP3871437B1 patent drawingFigure 2
  • EP3871437B1 patent drawingFigure 3

AI summary

Wireless communications systems and methods related to communications in an unlicensed spectrum with tight frequency reuse color coding are provided. A first wireless communication device communicates, with a second wireless communication device, a first reservation signal to reserve a first transmission opportunity (TXOP) in a spectrum shared by a plurality of network operating entities. The first reservation signal includes a first waveform sequence identifying at least a first network operating entity of the plurality of network operating entities associated with the first wireless communication device and the second wireless communication device. The first wireless communication device communicates, with the second wireless communication device, a first communication signal in the spectrum during the TXOP.