Radio Terminal PSFCH Resource Allocation for Sidelink Carrier Aggregation
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Solution Overview
Problem
In sidelink carrier aggregation for device-to-device communication, UEs with limited transmission capabilities face challenges in transmitting hybrid automatic repeat request (HARQ) feedback on multiple sidelink carriers simultaneously, due to overlapping Physical Sidelink Feedback Channel (PSFCH) transmissions.
Innovation Solution
A radio terminal is configured to receive sidelink transmissions on multiple carriers and transmit HARQ feedbacks using multiple PSFCH resources within an identical time slot, with options to delay or select which PSFCH transmission to perform if overlapping occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE transmits HARQ feedback on multiple sidelink carriers simultaneously using multiple PSFCH resources, then the reliability of sidelink communications is improved, but the transmission capability requirements increase and overlapping PSFCH transmissions occur
Solution Approach 1:
The patent segments the PSFCH transmission resources across multiple sidelink carriers, allowing the UE to transmit HARQ feedback on multiple carriers simultaneously using different PSFCH resources. This segmentation enables parallel feedback transmission, improving reliability while managing transmission capabilities through resource division.
Solution Approach 2:
The patent introduces an additional dimension for PSFCH resource allocation by utilizing multiple sidelink carriers (frequency dimension) and different time slots (time dimension). When overlapping is detected, the UE transitions to using resources in a different time dimension (next available PSFCH occasion) rather than conflicting frequency resources, thereby resolving the contradiction between reliability improvement and transmission capability constraints.
2Productivity
If PSFCH transmissions on multiple sidelink carriers occur in the same time slot, then HARQ feedback for multiple carriers is achieved, but resource conflict and transmission overlap occur
Solution Approach 1:
The patent implements preliminary detection of PSFCH resource overlap before transmission. The UE checks whether PSFCH resources on different sidelink carriers in the same time slot are available and non-overlapping. If overlap is detected, the UE proactively selects alternative resources in a different time slot, preventing resource conflict before it occurs and maintaining efficient feedback transmission.
Solution Approach 2:
The patent employs a feedback mechanism where the UE monitors the availability of PSFCH resources and adjusts its transmission strategy accordingly. When resource overlap is detected, the system provides feedback to select alternative resources, creating a closed-loop resource management approach that balances productivity and device complexity.
Data Source
AI summary
A radio terminal (1B) receives a first sidelink transmission from a peer radio terminal (1A) on a first sidelink carrier and receives a second sidelink transmission from the peer radio terminal (1A) on a second sidelink carrier. The radio terminal (1B) transmits a first HARQ feedback for the first sidelink transmission and a second HARQ feedback for the second sidelink transmission using a plurality of Physical Sidelink Feedback Channel (PSFCH) resources within an identical time slot in the first sidelink carrier. This can help, for example, to reduce or resolve a timing conflict in the transmission of multiple HARQ feedbacks for multiple sidelink receptions on multiple sidelink carriers.