Systems, methods, and devices for multiple-slot, consecutive, unlicensed sidelink transmissions
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Solution Overview
Problem
Current wireless communication technologies are limited to single-slot sidelink (SL) transmissions and lack the capability to efficiently select and reserve multiple consecutive slots for initial SL-U communications, leading to inefficient channel access and resource allocation in unlicensed spectrum scenarios.
Innovation Solution
The proposed solution enables the indication, selection, and allocation of SL resources for multiple consecutive slots in sidelink communications, allowing UEs to reserve resources using DCI and SCI, and incorporates higher layer parameters such as candidate resource slots, sub-channels, and data priority to manage conflicts and overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE performs listen-before-talk (LBT) and clear channel assessment (CCA) before each sidelink transmission in unlicensed spectrum, then channel access reliability is improved, but transmission latency and complexity increase due to repeated sensing requirements
Solution Approach 1:
The patent segments the LBT/CCA sensing requirement into two parts: a first LBT/CCA performed by the transmitting UE before initiating transmissions, and a second LBT/CCA performed by the receiving UE before transmitting HARQ feedback. This segmentation allows each UE to perform simplified sensing rather than requiring continuous complex sensing, thereby reducing overall device complexity while maintaining channel access reliability through distributed assessment.
Solution Approach 2:
The transmitting UE performs the first LBT/CCA in advance before initiating the sidelink transmission sequence. This preliminary action ensures the channel is clear before data transmission begins, establishing a foundation for reliable communication without requiring the receiving UE to perform complex continuous sensing, thus reducing overall system complexity while maintaining reliability.
2Reliability
If a UE performs LBT and CCA before each sidelink transmission to ensure channel availability, then transmission reliability is improved, but transmission delay increases due to repeated sensing time requirements
Solution Approach 1:
The patent divides the sensing responsibility into two segments: the transmitting UE performs LBT/CCA once before initiating transmissions, and the receiving UE performs LBT/CCA once before transmitting HARQ feedback. This segmentation eliminates the need for repeated sensing before each transmission within the configured grant period, thereby maintaining transmission reliability while significantly reducing transmission delay compared to performing sensing before every individual transmission.
Solution Approach 2:
Once the transmitting UE successfully performs the first LBT/CCA and initiates transmissions, the system maintains continuous useful action by allowing multiple transmissions without requiring repeated sensing. The receiving UE performs its LBT/CCA once before feedback transmission, enabling continuous communication flow. This continuity approach ensures reliability through initial channel assessment while minimizing time loss by avoiding repeated sensing delays.
3Productivity
If consecutive sidelink transmissions are performed in unlicensed spectrum without coordinated LBT/CCA, then spectral efficiency is improved, but interference and collision probability increase
Solution Approach 1:
The patent segments the interference management function between transmitting and receiving UEs. The transmitting UE performs the first LBT/CCA to assess channel conditions before initiating consecutive transmissions, while the receiving UE performs the second LBT/CCA before transmitting HARQ feedback. This segmentation coordinates the sensing actions of different devices, allowing consecutive transmissions to proceed with improved spectral efficiency while managing interference through distributed channel assessment.
Solution Approach 2:
The system implements feedback through HARQ acknowledgment transmissions from the receiving UE. The receiving UE performs LBT/CCA before sending this feedback, ensuring channel conditions are appropriate for feedback transmission. This feedback mechanism allows the transmitting UE to adapt subsequent transmissions based on received acknowledgments, improving spectral efficiency through successful retransmissions while managing interference through coordinated channel assessment at both ends.
Data Source
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AI summary
The techniques for enabling the indication, selection, allocation, and use of sidelink (SL) resources for SL communications using an unlicensed wireless spectrum (SL-U communications) and multiple, consecutive slots. One or more of these techniques may be applicable to scenarios in which SL resources are allocated by a base station and/or scenarios in which SL resources are allocated by use equipment (UEs). The SL resources may include a frequency domain, time domain, number of consecutive slots, etc., may be selected from a pool of SL-U resources, and may be indicated using downlink control information (DCI) and/or sidelink control information (SCI). The techniques may include allocating SL-U resources using additional or higher layer parameters, such as candidate SL resource slots, sub-channels, data priority values, a reference signal received power (RSRP), and more. The techniques may involve scenarios in which allocated SL resource conflict or overlap with a channel occupancy time (COT).