Adaptive Contention Window Adjustment in NR-U Communication Devices
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Solution Overview
Problem
In New Radio in Unlicensed Spectrum (NR-U), the contention window size cannot be adjusted adaptively in situations without HARQ feedback, leading to communication conflicts between multiple transmitters.
Innovation Solution
A processing method that determines the contention window size based on the channel state within a first reference duration and/or feedback information received within a second reference duration, allowing for adaptive adjustment of the contention window size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the contention window size is fixed without adaptive adjustment mechanisms, then the system complexity is reduced, but communication conflicts increase in NR-U environments without HARQ feedback
Solution Approach 1:
The terminal device autonomously adjusts the contention window size based on LBT results and channel occupancy ratios without requiring external control or HARQ feedback. The device monitors channel state independently and modifies its own transmission parameters, eliminating the need for complex network-controlled adjustment mechanisms while reducing communication conflicts.
Solution Approach 2:
The system uses internal feedback loops where the terminal device monitors its own LBT success/failure results and channel occupancy ratios, then uses this feedback to dynamically adjust the contention window size. This self-feedback mechanism enables adaptive conflict avoidance without requiring external HARQ feedback or complex network intervention.
2Reliability
If the contention window size is dynamically adjusted based on channel state and feedback information, then communication conflict avoidance is improved, but the device complexity increases
Solution Approach 1:
The terminal device changes the contention window size parameter dynamically based on monitored channel conditions. When LBT failure ratio or busy channel ratio exceeds thresholds, the device increases the contention window size to reduce conflicts. This parameter adjustment approach provides adaptive conflict avoidance using simple threshold-based logic rather than complex algorithms.
Solution Approach 2:
The contention window size transitions from a static fixed value to a dynamic adjustable parameter that adapts to changing channel conditions. The device continuously monitors LBT results and channel occupancy, then modifies the contention window size in real-time to match current traffic conditions and conflict levels, enabling flexible adaptation without complex mechanisms.
3Reliability
If the contention window size is increased to reduce communication conflicts, then the probability of conflict decreases, but the transmission delay increases
Solution Approach 1:
The contention window size is dynamically adjusted rather than permanently increased. The device increases the window size only when conflict indicators (LBT failure ratio, busy channel ratio) exceed thresholds, and can decrease or maintain it when conditions improve. This dynamic adjustment reduces average transmission delay compared to a permanently large contention window while still providing conflict avoidance when needed.
Solution Approach 2:
The system changes the contention window size parameter adaptively based on measured channel conditions rather than using a fixed large value. By adjusting the parameter only when necessary (when conflict indicators exceed thresholds), the system maintains low transmission delay during good conditions while providing conflict protection during congested periods.
Data Source
AI summary
Disclosed are a processing method, a communication device and a storage medium. The communication device determines the contention window size according to the channel state within the first reference duration and/or the feedback information received within the second reference duration. In the case of no HARQ feedback of the physical sidelink shared channel or in the case of only NACK feedback of the physical sidelink shared channel or in the case of a non-control/data channel, after the random backoff mechanism is started, the contention window size is determined according to the channel state within the first reference duration and/or the feedback information received within the second reference duration, so as to adjust the contention window size according to the occupancy of the channel and the information transmission situation, thereby realizing adaptive adjustment of the contention window size in the random backoff mechanism, and avoiding communication conflicts between multiple communication devices.