NR V2X Sidelink Scheduling in Unlicensed Spectrum with COT Sharing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing V2X communication systems face challenges in efficiently utilizing unlicensed spectrum for sidelink communications, particularly in scenarios where network coverage is limited or absent, leading to inefficiencies in channel access and data transmission.
Innovation Solution
A method for scheduling sidelink communications in unlicensed spectrum involves obtaining a grant for transmission, receiving channel occupancy time (COT) information, performing a listen-before-talk (LBT) procedure using specific parameters, and transmitting data based on successful LBT, with considerations for unicast or groupcast types and priority settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If V2X communications use unlicensed spectrum for sidelink transmissions, then spectrum utilization is improved, but channel access efficiency deteriorates due to lack of network coordination
Solution Approach 1:
The patent enables WTRUs to autonomously perform LBT procedures and determine COT sharing parameters without network coordination. Each WTRU independently senses the channel, determines whether to perform LBT, and decides on COT sharing based on received COT information from other WTRUs, making the system self-sufficient in unlicensed spectrum operations
Solution Approach 2:
The patent implements preliminary COT information exchange before actual data transmission. WTRUs transmit COT information indicating their channel occupancy status and intentions, allowing other WTRUs to make informed decisions about channel access and COT sharing before attempting transmission, thus improving channel access efficiency
2Adaptability or versatility
If WTRUs autonomously access channel in unlicensed spectrum, then network coverage requirements are reduced, but interference management becomes more difficult
Solution Approach 1:
The patent implements a feedback mechanism where WTRUs transmit COT information about their channel occupancy status, duration, and sharing intentions. Other WTRUs receive this feedback and adjust their LBT behavior accordingly, creating a coordinated interference management system even without network coverage
Solution Approach 2:
The patent dynamically adjusts LBT parameters such as contention window size and LBT category based on COT information from other WTRUs. WTRUs can switch between different LBT categories (e.g., from Category 4 to Category 2) depending on the channel conditions and COT sharing opportunities, optimizing interference management
3Reliability
If LBT procedure is performed for each transmission, then channel access reliability is improved, but transmission latency increases
Solution Approach 1:
The patent applies partial LBT procedures instead of full LBT for certain transmissions. When a WTRU receives COT information indicating an ongoing COT from another WTRU, it can perform a simplified LBT (such as Category 1 or Category 2 LBT) rather than a full Category 4 LBT, reducing latency while maintaining reliability through the COT sharing mechanism
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Methods and apparatuses for scheduling sidelink communications in unlicensed spectrum are disclosed. A method performed by a first wireless transmit/receive unit (WTRU) may comprise: obtaining a grant for transmission on a sidelink (SL); receiving, from a second WTRU or an additional WTRU, a transmission that includes first channel occupancy time (COT) information; on a condition that the grant is for transmission on the SL during a COT associated with the second WTRU or an additional WTRU, determining, from a transmission received from the second WTRU, the additional WTRU, or both the second and the additional WTRU, cast information; performing a listen before talk (LBT) procedure using a set of parameters associated with information received from the second WTRU or additional WTRU; and on a condition that the LBT procedure is successful, transmitting, based on the determined cast information, data that includes second COT information.