Adaptive Effective Contention Window for NR Sidelink
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Solution Overview
Problem
Current wireless communication systems face challenges in managing contention windows for New Radio (NR) sidelink communications over unlicensed bands, leading to inefficiencies and increased collisions due to interference from other radio access technologies, which affects channel access reliability and efficiency.
Innovation Solution
The implementation of adaptive effective contention windows (ECWs) for NR sidelink communications, which allow UEs to adjust contention window parameters based on channel access outcomes, enabling responsive resource selection and reducing collisions by increasing the window for failures and decreasing it for successes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed contention window parameters are used for NR sidelink communications over unlicensed bands, then device complexity is reduced, but channel access reliability deteriorates due to interference from other radio access technologies
Solution Approach 1:
The patent implements dynamic contention window adjustment where the contention window size is adapted based on channel access outcomes. The UE increases the contention window after failed channel access attempts and decreases it after successful access, transforming the static parameter into a dynamic one that responds to real-time channel conditions, thereby improving reliability without requiring complex centralized control
Solution Approach 2:
The patent employs feedback mechanisms where the UE monitors channel access outcomes (success or failure) and uses this feedback to adjust contention window parameters. This closed-loop control enables the system to adapt to interference patterns from other radio access technologies, improving channel access reliability through data-driven parameter optimization
2Reliability
If larger contention windows are used to reduce collisions, then channel access reliability improves, but resource utilization efficiency deteriorates due to increased waiting time
Solution Approach 1:
The patent dynamically adjusts contention window size based on actual channel access outcomes rather than using a consistently large window. After successful channel access, the contention window is decreased to allow faster resource selection and improve resource utilization. After failures, it is increased to reduce collisions. This dynamic behavior resolves the trade-off by adapting the window size to current conditions
Solution Approach 2:
The patent changes the contention window parameter adaptively based on channel access performance metrics. The system monitors access success rates and adjusts the contention window size accordingly, transforming it from a fixed parameter to a variable one that optimizes both reliability and efficiency under different operating conditions
3Productivity
If adaptive contention window adjustment is implemented, then resource utilization efficiency improves, but device complexity increases due to additional parameter management
Solution Approach 1:
The patent implements self-service mechanisms where the UE autonomously adjusts its own contention window parameters based on its own channel access outcomes. The device monitors its own access performance and automatically modifies parameters without requiring external control or complex coordination, enabling adaptive optimization while keeping implementation complexity manageable
Solution Approach 2:
The patent uses simple feedback loops where the UE monitors channel access outcomes and automatically adjusts contention window parameters in response. This feedback-driven approach enables adaptive resource utilization efficiency improvement through straightforward parameter adjustments based on observed performance, avoiding the need for complex centralized management systems
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may select, for a sidelink transmission over an unlicensed band and associated with a medium access control (MAC) protocol data unit (PDU), one or more candidate resources of a set of candidate resources that are within an adaptive effective contention window (ECW). The UE may adjust at least one parameter of the adaptive ECW to determine an adjusted at least one parameter based at least in part on a channel access output associated with the one or more candidate resources. The UE may transmit the MAC PDU using the one or more candidate resources or an additional one or more candidate resources, wherein the additional one or more candidate resources are selected based at least in part on the adjusted at least one parameter. Numerous other aspects are provided.