Sidelink Channel Access Using Fixed Sensing Periods
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting signals, particularly in scenarios requiring high reliability and low latency, such as sidelink communications involving services with high reliability requirements, where existing channel access methods are inefficient.
Innovation Solution
A user equipment (UE) in a wireless communication system employs a channel access method that includes receiving sidelink control information with channel occupancy sharing information and attempting transmission based on a fixed sensing period when specific conditions are met, rather than random backoff, to optimize channel access procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random backoff is used for channel access in sidelink communications, then collision avoidance is improved, but transmission latency increases and reliability deteriorates
Solution Approach 1:
The transmitting UE performs sensing during a fixed sensing period before transmission to detect channel occupancy and predict potential collisions in advance. This preliminary action allows the UE to make informed transmission decisions without relying on random backoff, thereby reducing latency while maintaining reliability through proactive collision avoidance.
Solution Approach 2:
The system uses sensing results as feedback to determine transmission timing. The transmitting UE continuously monitors the channel during the fixed sensing period, receives feedback about channel occupancy from other UEs, and adjusts transmission timing based on this feedback. This closed-loop approach eliminates the need for random backoff while ensuring reliable transmission.
2Productivity
If fixed sensing period is used for channel access, then transmission latency is reduced and productivity is improved, but channel access collision risk increases
Solution Approach 1:
The fixed sensing period establishes a predetermined time window before transmission where the UE must sense the channel. This preliminary action ensures that the UE has sufficient time to detect other transmissions and avoid collisions, while the fixed duration maintains high channel access efficiency by preventing excessive delays.
Solution Approach 2:
The system changes the channel access parameter from random backoff duration to a fixed sensing period. This parameter change standardizes the channel access process, improving productivity by eliminating random delays, while the fixed duration is calibrated to provide sufficient sensing time for collision avoidance.
3Productivity
If channel occupancy sharing information is used, then resource utilization is improved, but system complexity increases
Solution Approach 1:
The sensing procedure serves multiple functions simultaneously: it detects channel occupancy, receives occupancy sharing information from other UEs, determines transmission timing, and avoids collisions. This multi-functionality improves resource utilization without requiring separate mechanisms for each task, thereby limiting the increase in system complexity.
Solution Approach 2:
The system uses the existing sensing mechanism to automatically acquire and process channel occupancy sharing information without requiring additional complex protocols. Each UE independently performs sensing, interprets occupancy information from others, and makes transmission decisions, enabling self-service operation that improves resource utilization while maintaining manageable complexity.
Data Source
AI summary
The present invention relates to a wireless communication system and, particularly, to a method and a wireless device therefor, the method comprising the steps of: receiving, from a first UE, SCI including CO sharing information; receiving, from the first UE, in an RB set, a PSSCH corresponding to the SCI; and attempting SL transmission after the reception of the PSSCH, wherein, if a condition is satisfied, the SL transmission is attempted according to a CAP based on a fixed sensing period.