Base Station LAA Parameter Handling for Unlicensed Band Interference

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Solution Overview

Problem

Current 3GPP specifications do not define the necessary functions for Radio Units (RUs) to detect the usage state of unlicensed bands in a Centralized Radio Access Network (C-RAN), which is crucial for preventing interference with other radio systems using the same band in License-Assisted Access (LAA) configurations.

Innovation Solution

The proposed solution involves a base station configuration where the Central Digital Unit (DU) generates and transmits LAA processing parameters to the RU, enabling the RU to perform Listen Before Talk (LBT) processes, including determining the backoff time, carrier sense time, and unlicensed band frequency range, to assess and manage the use state of the unlicensed band, thereby ensuring interference-free communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If LAA functions are implemented in C-RAN with DU and RU architecture, then communication efficiency in unlicensed bands is improved, but the specification definition for LBT detection function location is unclear

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidspecification clarity
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the LAA functionality by separating the LBT detection function from the data transmission function. The RU is assigned the LBT detection function while the DU handles data transmission, creating a clear functional division that resolves the specification ambiguity and enables efficient unlicensed band communication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a parameter transmission mechanism as an intermediary between DU and RU. The DU transmits parameters to the RU, which then performs LBT detection based on these parameters. This intermediary mechanism clarifies the interaction protocol and resolves the specification uncertainty about function location.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If RU performs LBT detection function, then interference with other radio systems is reduced, but current specifications do not define this function

Engineering Contradiction:
ImproveinterferenceVSAvoidspecification complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the LBT detection function from the DU and assigns it to the RU. This extraction reduces interference by enabling localized spectrum sensing at the RU, while the specification complexity is managed by clearly defining the parameter transmission interface between DU and RU.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If LBT parameters are transmitted from DU to RU, then detection accuracy is improved, but information transmission overhead increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidinformation transmission
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by transmitting specific LBT parameters only to the RU that needs them for detection. This targeted parameter transmission improves detection accuracy at the local RU level while minimizing overall information transmission overhead by avoiding redundant parameter distribution.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3410761B1Base station and transmission method
Publication Date: 2022.06.01 NTT DOCOMO INC
  • EP3410761B1 patent drawingFigure 1
  • EP3410761B1 patent drawingFigure 2
  • EP3410761B1 patent drawingFigure 3

AI summary

A base station used as a first base station in a wireless communication system including the first base station, a second base station that communicates with the first base station, and a user equipment that communicates with the first base station includes: a reception unit that receives a parameter used for performing communication in a specific band and data to be transmitted toward the user equipment from the second base station; and a detection unit that performs a process of detecting a use state of the specific band according to the parameter when the data is transmitted to the user equipment.