LAA Base Station Channel Access in Unlicensed Bands

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Solution Overview

Problem

Existing mobile communication systems face challenges in efficiently utilizing unlicensed band frequencies due to regulatory requirements, leading to potential interference with other unlicensed band apparatuses and limited capacity, necessitating a method to maximize channel usage while ensuring fair coexistence.

Innovation Solution

The implementation of a License Assisted Access (LAA) base station that performs channel sensing using an energy detect scheme, determines channel occupancy, and transmits reservation signals to ensure fair sharing, allowing data transmission only when the channel is empty, and dynamically adjusts transmission and idle periods based on regulatory requirements and environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the base station always occupies unlicensed band frequency to provide mobile communication service, then service continuity is improved, but other unlicensed band apparatuses cannot use the frequency

Engineering Contradiction:

Improveservice continuityVSAvoidfrequency sharing capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The base station performs periodic channel sensing (Clear Channel Assessment) and alternates between transmission periods and idle periods. During transmission periods, the base station occupies the unlicensed band for data transmission, while during idle periods, it releases the channel to allow other unlicensed band apparatuses to use the frequency. This periodic occupation pattern ensures both service continuity for mobile users and fair sharing with other devices.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The base station performs Clear Channel Assessment (CCA) before initiating data transmission to detect whether the channel is currently occupied by other apparatuses. This preliminary sensing action prevents interference with other unlicensed band devices and ensures the base station only transmits when the channel is clear, thereby maintaining both service reliability and fair coexistence.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the base station performs channel sensing and transmits reservation signals, then fair coexistence with other unlicensed band apparatuses is improved, but channel occupancy time is reduced

Engineering Contradiction:

Improvefair coexistence capabilityVSAvoidchannel occupancy time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The base station performs channel sensing and transmits reservation signals only for the minimum necessary duration required to indicate channel occupancy to other devices. Rather than occupying the channel for the maximum possible time, the base station uses just enough sensing and reservation signaling to ensure fair coexistence, thereby minimizing the loss of channel occupancy time while still achieving fair sharing objectives.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If many parts of basic functions are changed to observe regulatory requirements, then compliance with unlicensed band regulations is improved, but development period and costs are increased

Engineering Contradiction:

Improveregulatory complianceVSAvoidsystem development complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The base station implements a multi-functional channel access mechanism that combines Clear Channel Assessment, reservation signal transmission, and dynamic transmission/idle period adjustment within a single integrated system. This universal approach allows the base station to comply with unlicensed band regulatory requirements while maintaining compatibility with existing licensed band operations, thereby avoiding the need for separate dedicated systems and reducing overall development complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables the LAA system to effectively utilize unlicensed band frequencies, ensuring fair coexistence with other unlicensed band apparatuses, maximizing channel occupancy time, and maintaining compliance with regulatory requirements, thereby enhancing the capacity and efficiency of mobile communication services.

Implementation Method 1

performs channel sensing using an energy detect scheme

Methodology Applied

Scientific EffectEnergy detect scheme:

Data Source

PatentEP3200547B1Wireless channel access method and device

Publication Date: 2021.08.18 ELECTRONICS & TELECOMM RES INST

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Figure 3(A)~3(C)

AI summary

Disclosed are a base station and a channel access method performing a channel access in a unlicensed band. The channel access method includes: performing channel sensing at least once on a channel of the unlicensed band in a channel sensing period of a frame; and broadcasting a reservation signal for the channel when the channel is empty.