HARQ Transmission Resource Switching for Unlicensed Band Stability
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Solution Overview
Problem
In unlicensed bands, wireless communication devices face instability due to failed Listen Before Talk (LBT) operations, leading to unsuccessful transmission of necessary information and instability in wireless communication links.
Innovation Solution
A wireless communication device and method that determines channel availability and uses a first or second resource for Hybrid Automatic Repeat Request (HARQ) transmission, switching to the second resource if the first resource fails, and sets resources for HARQ transmission to ensure stable communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Listen Before Talk (LBT) is performed to sense the channel before transmission in unlicensed bands, then channel fairness and coexistence with other nodes are improved, but transmission reliability deteriorates because the device may be unable to transmit when the channel is busy
Solution Approach 1:
The base station performs preliminary action by pre-configuring multiple uplink control channel resources (first resource and second resource) for the terminal device before transmission occurs. When the first resource becomes unavailable due to LBT failure, the terminal can immediately use the pre-configured second resource without requiring additional negotiation or signaling, thus maintaining transmission reliability while preserving channel fairness through LBT
Solution Approach 2:
The system provides beforehand cushioning by preparing alternative uplink control channel resources (second resource) in advance as a backup. This cushioning mechanism ensures that when the primary transmission path (first resource) fails due to LBT constraints, the terminal device has an immediate fallback option, preventing communication link instability without compromising channel access fairness
2Device complexity
If a single uplink control channel resource is used for HARQ transmission, then device complexity is reduced, but communication stability deteriorates because the transmission may fail when the channel is busy
Solution Approach 1:
Multiple uplink control channel resources are pre-configured in advance by the base station, including a first resource for normal transmission and a second resource for fallback transmission. This preliminary configuration eliminates the need for complex real-time resource negotiation and selection logic in both the base station and terminal, while ensuring communication stability through the availability of alternative resources when LBT fails
Solution Approach 2:
The second uplink control channel resource acts as an intermediary backup path. When the first resource transmission fails due to LBT constraints, the terminal device switches to the second resource as an intermediate solution to maintain communication stability. This intermediary resource simplifies the overall system by providing a straightforward fallback mechanism without requiring complex reconfiguration or negotiation protocols
Data Source
AI summary
There is provided a wireless communication device including a determination unit configured to determine whether a channel is clear or busy, and a transmission processing unit configured to transmit a hybrid ARQ (HARQ) to a communication device of a communication partner, in which the HARQ is transmitted using a first resource or a second resource, and in a case where transmission of the HARQ using the first resource has been failed through the determination by the carrier sense unit, the transmission processing unit transmits a HARQ using the second resource.