Unlicensed Spectrum Base Station Synchronization Method

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Solution Overview

Problem

The limited time availability of unlicensed spectrum resources in wireless communication systems hampers continuous data transmission due to the need for continuous detection of spectrum usage, leading to reduced utilization as existing synchronization methods are inefficient in achieving downlink synchronization within the short available time.

Innovation Solution

An unlicensed-spectrum base station preemptively sends synchronization signals intensively between a first time point and a second time point, where the second time point marks the start of an effective subframe, allowing user equipment to complete downlink synchronization quickly and initiate data transmission early, thereby improving spectrum resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If existing synchronization methods are used in unlicensed spectrum cells, then downlink synchronization can be achieved, but the synchronization time is too long which reduces the time available for data transmission

Engineering Contradiction:
Improvesynchronization timeVSAvoiddata transmission time
Core Design Contradiction:
Loss of timeVSProductivity

Solution Approach 1:

The base station sends synchronization signals in advance during the preemption period before the effective subframe starts. This preliminary action allows user equipment to complete downlink synchronization before data transmission begins, reducing the loss of time and increasing the time available for productive data transmission in unlicensed spectrum cells.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the base station continuously detects unlicensed spectrum usage, then spectrum collision can be avoided, but the unlicensed spectrum cannot be occupied continuously reducing resource utilization

Engineering Contradiction:
Improvespectrum collision avoidanceVSAvoidspectrum resource utilization
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The base station performs periodic carrier sensing and occupies the unlicensed spectrum in periodic intervals rather than continuously. This allows the system to maintain reliability by detecting spectrum availability while improving productivity by maximizing the utilization of available unlicensed spectrum resources through repeated occupation cycles.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3091799B1Synchronization method, base station, and user equipment
Publication Date: 2020.01.01 HUAWEI TECH CO LTD
  • EP3091799B1 patent drawingFigure 1~2
  • EP3091799B1 patent drawingFigure 3
  • EP3091799B1 patent drawingFigure 4

AI summary

Embodiments of the present invention provide a synchronization method, a base station, and user equipment. The method includes: completing, by an unlicensed-spectrum base station, preemption of a radio channel of an unlicensed spectrum at a first time point; determining, by the unlicensed-spectrum base station, a second time point, where the second time point is a subframe boundary at which the base station starts to send an effective subframe; intensively sending, by the unlicensed-spectrum base station, synchronization signals in a first time period between the first time point and the second time point, so that user equipment UE completes uplink synchronization in the first time period; and starting, by the base station, to send the effective subframe at the second time point. According to the embodiments of the present invention, after preempting the radio channel of the unlicensed spectrum, the unlicensed-spectrum base station intensively sends the synchronization signal. Therefore, the UE completes synchronization with an unlicensed-spectrum cell or base station in a short time, to start to perform data transmission by using the unlicensed spectrum as early as possible, thereby improving utilization of an unlicensed spectrum resource.