LBT Failure Reporting for Sidelink Throughput
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Solution Overview
Problem
Wireless communication systems face inefficiencies in sidelink communications due to the inability to differentiate between listen-before-talk (LBT) failures and decoding failures, leading to flawed scheduling decisions and reduced throughput in shared radio frequency spectrum access.
Innovation Solution
A method where user equipment (UE) reports the results of LBT for multiple transmission time intervals (TTIs) to the base station, allowing the base station to schedule subsequent sidelink transmissions based on successful access, thereby improving scheduling and increasing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base station schedules sidelink transmissions without differentiated LBT failure reporting, then the scheduling process is simple, but the scheduling accuracy and throughput are reduced
Solution Approach 1:
The patent segments the feedback information into separate LBT outcome bits and HARQ feedback bits. The LBT outcome bits indicate whether the listen-before-talk procedure succeeded or failed for each TTI, while HARQ feedback indicates whether the received data was correctly decoded. This segmentation allows the base station to differentiate between LBT failures and decoding failures, improving scheduling accuracy without creating an overly complex reporting mechanism.
Solution Approach 2:
The patent implements a feedback mechanism where the UE reports LBT outcomes to the base station for multiple TTIs. The base station uses this feedback information to make more informed scheduling decisions for subsequent transmissions, thereby improving scheduling accuracy and throughput while maintaining manageable system complexity through structured feedback protocols.
2Productivity
If the UE reports LBT results for multiple TTIs, then the base station can improve scheduling decisions, but the control channel overhead increases
Solution Approach 1:
The patent merges the LBT outcome reporting with the existing HARQ feedback mechanism. Both LBT outcome bits and HARQ feedback bits are transmitted together in the same uplink control channel, allowing the base station to receive comprehensive feedback (LBT status and decoding status) without proportionally increasing control channel overhead. This combining approach enables improved scheduling decisions while minimizing additional overhead.
Solution Approach 2:
The patent reports LBT outcomes for multiple TTIs selectively - only when necessary for improved scheduling. The base station can configure the UE to report LBT outcomes for specific TTIs based on scheduling needs, avoiding unnecessary reporting for all TTIs and thus reducing control channel overhead while still achieving the desired scheduling improvements where needed.
3Productivity
If the base station schedules without LBT outcome information, then the scheduling process is faster, but the resource utilization is suboptimal
Solution Approach 1:
The patent implements preliminary action by having the UE perform LBT procedures in advance for multiple TTIs before actual data transmission. The LBT outcomes are reported to the base station, which then uses this advance information to make informed scheduling decisions. This preliminary LBT action allows the base station to optimize resource allocation for subsequent transmissions, improving resource utilization while the structured reporting timing minimizes scheduling delay.
Data Source
AI summary
Techniques for wireless communications are described. A user equipment (UE) may receive downlink control information (DCI) scheduling sidelink transmissions in one or more sets of multiple transmission time intervals (TTIs) over a shared spectrum. The UE may perform a listen-before-talk (LBT) for one or more of the TTIs in the one or more sets of multiple TTIs, and the UE may transmit, to a base station, an indication of results of the LBT performed for the one or more TTIs. Because the UE may provide the results of the LBT to the base station, the base station may be able to schedule sidelink transmissions from the UE based on the results of the LBT. As such, the UE may experience increased throughput in sidelink communications since the scheduling at the base station may be improved.