SCI-Guided Sidelink Reservations with Mini-Slot Fallback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication systems face inefficiencies and reliability issues due to unsuccessful listen-before-talk (LBT) procedures in resource reservation for sidelink communications, leading to delayed or canceled transmissions in shared radio frequency spectrum bands.
Innovation Solution
Implementing techniques such as mini-slot transmissions, cyclic prefix extensions (CPEs), and resource reservation bursts, along with using sidelink control information (SCI) to reserve resources, perform LBT procedures, and multiplex SCI with sidelink synchronization signal blocks (S-SSB) to enhance resource utilization and reduce collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If LBT procedure is performed before accessing reserved resources, then collision avoidance is improved, but transmission delay increases when LBT fails
Solution Approach 1:
The UE performs LBT procedure in advance before accessing reserved resources. If LBT succeeds, the UE transmits at the reserved resource. If LBT fails, the UE has already performed the preliminary channel assessment and can quickly switch to alternative actions (mini-slot transmission or CPE) without waiting for the reserved resource time, thus reducing the overall transmission delay while maintaining collision avoidance benefits
Solution Approach 2:
The patent introduces mini-slot transmission and cyclic prefix extension (CPE) as intermediary transmission mechanisms. When LBT fails before the reserved resource, these intermediaries allow the UE to perform partial or alternative transmissions, bridging the gap between LBT failure and the original reserved resource time, thereby reducing transmission delay while still avoiding collisions with other users who successfully performed LBT
2Productivity
If resource reservation is implemented in shared spectrum, then resource utilization efficiency is improved, but transmission reliability deteriorates due to LBT failures
Solution Approach 1:
The UE performs LBT procedure in advance of the reserved resource transmission time. This preliminary channel assessment allows the system to identify potential transmission failures before committing to the reserved resource, enabling timely fallback to alternative transmission mechanisms (mini-slot or CPE) and thus maintaining reliability while preserving resource reservation efficiency
Solution Approach 2:
The patent prepares alternative transmission paths (mini-slot and CPE) in advance as cushioning measures against LBT failures. When LBT fails, these pre-prepared alternatives immediately take over, cushioning the impact of transmission failure and maintaining reliability without compromising the overall resource utilization efficiency of the reservation system
3Loss of time
If mini-slot transmission is used when LBT fails, then transmission latency is reduced, but resource collision risk increases
Solution Approach 1:
The UE performs LBT procedure and receives feedback about channel availability. Based on this feedback, the UE intelligently decides whether to use mini-slot transmission or wait for the reserved resource. This feedback-driven decision-making reduces blind transmissions that could cause collisions, while still allowing low-latency mini-slot transmission when the channel is confirmed available
Solution Approach 2:
When LBT fails before the reserved resource, the UE performs a partial transmission action using mini-slot or CPE instead of waiting for the full reserved resource time. This partial action reduces transmission latency while the initial LBT failure indication serves as a warning to perform additional channel checks, thereby managing collision risk while achieving lower latency
4Productivity
If CPE is used to access sub-channel before reserved resource, then resource access efficiency is improved, but device complexity increases
Solution Approach 1:
The UE performs CPE by extending the cyclic prefix to access the sub-channel before the reserved resource time. This preliminary action allows the UE to secure the channel early and transmit data ahead of the scheduled reserved resource, improving resource access efficiency. The CPE mechanism is a standardized feature in OFDM systems, so while it adds some complexity, it leverages existing device capabilities rather than requiring entirely new functionality
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit sidelink control information (SCI) that indicates a set of resources reserved for sidelink communications at the UE. Each of the reserved resources may include a respective slot and a respective sub-channel of a shared radio frequency channel. The UE may perform a listen-before-talk (LBT) procedure associated with a sub-channel of a reserved resource prior to accessing the reserved resource. In some examples, the UE may perform a mini-slot transmission if the LBT procedure is unsuccessful. In other examples, the UE may use a cyclic prefix extension (CPE) to access the sub-channel before a start of the reserved resource. In some examples, the reserved resource may span two or more consecutive slots with the same sub-channel index. The described techniques may enable the UE to perform sidelink communications with greater reliability and higher throughput.