UE Downlink Acknowledgement in Shared Spectrum via LBT
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Solution Overview
Problem
There is a need for an apparatus and method to determine the acknowledgement of a downlink channel in an uplink transmission in wireless communication systems operating in a shared spectrum, particularly for semi-persistent scheduled (SPS) PDSCH transmissions, to enhance communication performance and reliability.
Innovation Solution
The method involves configuring user equipment (UE) and base stations to perform channel access procedures, including receiving and reporting acknowledgements of downlink channels through physical uplink control channel (PUCCH) transmissions, using HARQ-ACK information and RRC parameters to indicate channel occupancy and monitor control information, ensuring accurate acknowledgement of PDSCH transmissions in uplink communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If channel access procedures are implemented in shared spectrum, then coexistence and fairness are improved, but communication reliability deteriorates due to uncertain channel availability
Solution Approach 1:
The patent applies preliminary action by performing channel sensing (LBT) before actual data transmission. The device checks channel availability in advance and prepares transmission resources beforehand, ensuring that when the channel becomes available, transmission can immediately proceed without interruption, thus maintaining reliability in shared spectrum environments
2Adaptability or versatility
If LBT mechanism is used for channel access, then fairness in spectrum usage is improved, but transmission delay increases due to channel occupancy time limits
Solution Approach 1:
The patent applies dynamics by making the channel access strategy adaptive rather than static. The device dynamically adjusts its transmission behavior based on real-time channel conditions, LBT outcomes, and MCOT constraints. When channel is available, transmission proceeds immediately; when blocked, the device waits and retries, creating a flexible time-based adaptation that balances fairness with delay optimization
3Productivity
If SPS PDSCH transmission is used, then spectral efficiency is improved, but acknowledgement determination becomes complex in uplink transmissions
Solution Approach 1:
The patent applies feedback by implementing explicit acknowledgement mechanisms for SPS PDSCH transmissions. The receiving device sends HARQ-ACK feedback to confirm successful reception, and the transmitting device uses this feedback to determine whether retransmission is needed. This feedback loop simplifies the acknowledgement determination process by providing clear, standardized signals rather than requiring complex inference
Data Source
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AI summary
An apparatus and a method of wireless communication are provided. The method by a user equipment (UE) includes being configured, by a base station, to receive a downlink channel in a set of symbols for a serving cell and reporting, to the base station, an acknowledgement of the downlink channel in an uplink transmission. This can solve issues in the prior art, provide a method to determine an acknowledgement of a downlink channel in an uplink transmission, reduce signaling overhead, provide a good communication performance, and/or provide high reliability.