Carrier Switching for Unlicensed Data Retransmission

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Solution Overview

Problem

In wireless communications networks, data retransmission on unlicensed carriers is hindered by the need to preempt channels, leading to interruptions in Hybrid Automatic Repeat Request (HARQ) processes, as devices cannot continuously occupy unlicensed carriers.

Innovation Solution

A method where a first device transmits data using an unlicensed carrier and, upon determining the carrier is unavailable, retransmits the data using a second carrier, which can be either licensed or unlicensed, allowing continuous data transmission without channel preemption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If data is transmitted using an unlicensed carrier, then data throughput is improved, but channel availability is reduced due to preemption requirements

Engineering Contradiction:
Improvedata throughputVSAvoidchannel availability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the parameter of carrier type from single unlicensed carrier to dual carrier (licensed + unlicensed), allowing the system to switch between carriers based on availability. This parameter change enables maintaining high throughput when unlicensed carrier is available while ensuring reliability by falling back to licensed carrier when unlicensed carrier is preempted.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The licensed carrier acts as an intermediary backup resource. When the unlicensed carrier becomes unavailable due to preemption, the system uses the licensed carrier as a mediator to continue HARQ retransmission, thus maintaining channel availability and reliability without completely losing the throughput benefits of unlicensed spectrum.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a device preempts the unlicensed carrier again after occupying it for a specific time, then channel access compliance is improved, but HARQ retransmission continuity is interrupted

Engineering Contradiction:
Improvechannel access complianceVSAvoidHARQ retransmission continuity
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent establishes continuity of HARQ retransmission by creating a seamless handover mechanism between carriers. When the unlicensed carrier must be preempted for compliance, the system maintains continuous useful action by switching the retransmission to the licensed carrier, ensuring the HARQ process continues without interruption despite the preemption event.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system dynamically switches between unlicensed and licensed carriers based on real-time channel availability and preemption status. This dynamic behavior allows the system to comply with channel access requirements while maintaining HARQ continuity, adapting the transmission medium according to changing conditions rather than being static on a single carrier.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the sending device needs to preempt the channel again on the unlicensed carrier, then spectrum sharing fairness is improved, but data retransmission reliability is reduced

Engineering Contradiction:
Improvespectrum sharing fairnessVSAvoiddata retransmission reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent makes the communication system multi-functional by enabling it to operate on both unlicensed and licensed carriers for HARQ retransmission. This universality allows the system to share unlicensed spectrum fairly with other users while maintaining reliable data retransmission by having the licensed carrier as a backup function, thus resolving the conflict between spectrum sharing fairness and retransmission reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3267611B1Method, device, and system for data retransmission
Publication Date: 2021.06.09 HUAWEI TECH CO LTD
  • EP3267611B1 patent drawingFigure 1~2
  • EP3267611B1 patent drawingFigure 3~4
  • EP3267611B1 patent drawingFigure 5~6

AI summary

The present invention discloses a data retransmission method, a device, and a system, and relates to the communications field, so as to resolve a prior-art problem that when a device transmits data by using an unlicensed carrier, the data cannot be retransmitted because a channel needs to be preempted again. A specific solution is as follows: A first device transmits data to a second device by using a first carrier, where the first carrier is an unlicensed carrier. The first device obtains status information of the first carrier, where the status information is used to determine whether the first carrier is available. When the first carrier is unavailable, the first device retransmits the data to the second device by using a second carrier, where the first carrier and the second carrier are different carriers. The present invention is used for data retransmission.