NR Sidelink COT Sharing With Flexible HARQ Feedback
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Solution Overview
Problem
Existing wireless communication systems face challenges in NR sidelink resource and channel structure design for unlicensed bands, including channel occupancy time sharing, physical layer structure for cyclic prefix extension, physical sidelink feedback channel capacity, PSFCH resource locations, and transmission dropping due to LBT failure.
Innovation Solution
A wireless communication method and user equipment (UE) that performs channel occupancy time initiating based on a channel access scheme, transmits sidelink data and control information within the COT, and receives sidelink HARQ feedback, with flexible PSFCH resource indication and multi-slot scheduling to enhance channel access reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If channel occupancy time sharing is implemented for NR sidelink in unlicensed bands, then channel access efficiency is improved, but channel access reliability deteriorates due to LBT failure and transmission dropping
Solution Approach 1:
The patent applies preliminary action by performing Listen-Before-Talk (LBT) channel access procedure before initiating channel occupancy time (COT) for sidelink transmissions. The UE checks channel availability in advance and only initiates COT when the channel is clear, preventing transmission drops and ensuring reliable channel access before data transmission begins
Solution Approach 2:
The patent implements feedback mechanisms through sidelink hybrid automatic repeat request (HARQ) feedback and channel state information (CSI) reports. The receiving UE provides HARQ acknowledgments and channel quality feedback to the transmitting UE, enabling adaptive retransmissions and channel access parameter adjustments to maintain reliability in shared unlicensed spectrum
2Reliability
If PSFCH resources are allocated for sidelink feedback, then HARQ feedback capability is improved, but resource capacity is insufficient due to limited feedback channel resources
Solution Approach 1:
The patent segments the feedback channel resources by allocating different physical sidelink feedback channel (PSFCH) resources to different sidelink logical channels and priority levels. This segmentation allows multiple feedback streams to coexist with limited resources, enabling comprehensive HARQ feedback capability while efficiently utilizing the available feedback channel capacity
Solution Approach 2:
The patent extends feedback resources by utilizing both time and frequency dimensions. PSFCH resources are allocated across multiple time slots and frequency resources within the sidelink carrier, effectively increasing the total feedback channel capacity beyond what would be available in a single time-frequency instance
3Productivity
If multi-slot scheduling is implemented for sidelink data transmission, then resource utilization is improved, but channel occupancy time management becomes more complex
Solution Approach 1:
The patent applies preliminary action by performing channel access and COT initiation before multi-slot sidelink data transmissions. The transmitting UE secures the channel in advance and maintains COT across multiple scheduled slots, eliminating the need for repeated LBT procedures and simplifying channel occupancy management while enabling efficient multi-slot resource utilization
Solution Approach 2:
The patent ensures continuity of useful action by maintaining channel occupancy across multiple scheduled slots without requiring repeated channel access procedures. Once COT is acquired, the UE can continuously transmit sidelink data across multiple slots, maximizing resource utilization while avoiding the complexity of repeated channel access negotiations
4Reliability
If cyclic prefix extension is supported in NR sidelink, then coverage and robustness are improved, but physical layer structure complexity increases
Solution Approach 1:
The patent implements dynamic switching between normal cyclic prefix and extended cyclic prefix configurations based on channel conditions and service requirements. The physical layer structure adapts its cyclic prefix length dynamically, providing enhanced coverage and robustness when needed while maintaining simpler structures for normal conditions, thereby managing complexity through adaptive configuration
Data Source
AI summary
A wireless communication method. An initiating user equipment (UE) performs channel occupancy time (COT) initiating for a COT based on a channel access scheme and transmits sidelink data and sidelink control information within the COT. A responding UE receives the sidelink data and sidelink control information within the COT and performs a channel access scheme to use the shared COT. The responding UE transmits a sidelink hybrid automatic repeat request (HARQ) feedback in response to the sidelink data. The initiating receives the sidelink HARQ feedback.