Sidelink HARQ Codebook Reporting Across Uu and V2X Links
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Solution Overview
Problem
Wireless user devices face challenges in reporting Hybrid Automatic Repeat Request (HARQ) feedback information effectively to base stations in vehicle-to-everything (V2X) communications, particularly in determining and transmitting HARQ codebooks across different communication links.
Innovation Solution
A method and apparatus for determining a Hybrid Automatic Repeat Request (HARQ) codebook in V2X communication, involving transmitting HARQ feedback information through Physical Sidelink Shared Channel (PSSCH) and configuring a sidelink HARQ codebook based on PSSCH/Physical Sidelink Feedback Channel (PSFCH) occasions, with multiplexing and reporting to a base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple HARQ feedback information from different links (Uu link/SL link) are transmitted to the base station through the same physical resource, then the reporting efficiency is improved, but the codebook determination complexity increases
Solution Approach 1:
The patent segments the HARQ feedback codebook into separate components: a first codebook for Uu link HARQ feedback and a second codebook for sidelink HARQ feedback. This segmentation allows each codebook to be determined independently based on its specific link characteristics, while both are multiplexed together for transmission, resolving the contradiction between reporting efficiency and codebook determination complexity.
Solution Approach 2:
The patent introduces a new dimension for codebook determination by considering both link type (Uu link and sidelink) and timing information (slot index, subframe index) as separate determining factors. This multi-dimensional approach allows the codebook to be constructed systematically from multiple independent parameters, simplifying the overall determination process while enabling efficient multiplexed reporting.
2Loss of time
If HARQ feedback timing is optimized for low latency, then communication latency is reduced, but the reliability of feedback transmission may be compromised
Solution Approach 1:
The patent applies preliminary action by pre-configuring the HARQ feedback timing parameters and codebook structures before actual feedback transmission. The codebook determination is prepared in advance based on configured parameters, allowing the feedback to be transmitted with minimal processing delay while maintaining reliability through predetermined timing arrangements.
Solution Approach 2:
The patent implements feedback mechanisms where the base station receives HARQ feedback information from the user equipment and uses this feedback to adjust future transmission parameters. This closed-loop feedback system ensures that timing optimizations do not compromise reliability, as the system can adapt based on actual feedback received.
3Loss of information
If the codebook size is increased to include all possible HARQ feedback information, then the completeness of feedback reporting is improved, but the transmission resource consumption increases
Solution Approach 1:
The patent applies partial action by constructing the codebook to include only the necessary HARQ feedback information for each link type, rather than attempting to include all possible feedback scenarios. The codebook is determined based on actual transmission configurations and link states, ensuring completeness for relevant feedback while avoiding unnecessary resource consumption for unrelated feedback information.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the codebook size and composition based on transmission parameters such as the number of configured downlink slots, the type of link (Uu or sidelink), and the specific timing information available. This flexible parameter adjustment allows the codebook to be optimized for each specific transmission scenario, balancing completeness with resource efficiency.
Data Source
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AI summary
A wireless user device (2650) comprising: an antenna; a processor; and a memory. The memory is storing instructions that, when executed by the processor, cause the wireless user device (2650) to receive, from a base station (2600), sidelink downlink control information, SL DCI, comprising a first indicator field that indicates a sidelink hybrid automatic repeat request, HARQ, feedback timing; based on the SL DCI, transmit, to one or more second wireless user devices, a plurality of sidelink signals via a first quantity of sidelink channel resources; during a first time interval, receive, from the one or more second wireless user devices, first sidelink HARQ feedback information responsive to the plurality of sidelink signals, wherein a second time interval is determined based on the sidelink HARQ feedback timing and based on the first time interval; determine, based on a ratio between a sidelink subcarrier spacing, SCS, configuration and an uplink SCS configuration and based on the first quantity, a sidelink HARQ codebook; and during the second time interval and based on the sidelink HARQ codebook, transmit, to the base station (2600), an uplink signal indicating the first sidelink HARQ feedback information.