NR-U Sidelink Resource Allocation With Time-Gap LBT Scheduling
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently allocating resources for sidelink transmissions in unlicensed spectrum, particularly in mode 1, due to potential collisions with WiFi transmissions and the need for Listen Before Talk (LBT) operations, which are not adequately addressed by current mechanisms.
Innovation Solution
The proposed solution involves enhancing mode 1 resource allocation by incorporating a time gap field in DCI 3_0 for unlicensed sidelink transmissions, supporting Type 1 and Type 2 LBT operations, and implementing a resource re-evaluation and pre-emption process to prevent collisions, while ensuring sufficient time for LBT sensing and HARQ feedback timing adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mode 1 resource allocation is used for unlicensed spectrum, then sidelink transmissions can be established, but collisions with WiFi transmissions occur due to insufficient LBT operation time
Solution Approach 1:
The patent applies preliminary action by performing resource re-evaluation and pre-emption checks before the actual sidelink transmission. The UE evaluates whether to proceed with the allocated resource based on current channel conditions and WiFi presence detection prior to transmission, thereby avoiding collisions while maintaining efficient spectrum utilization.
Solution Approach 2:
The patent implements dynamics by making the LBT sensing duration flexible rather than fixed. The sensing time is dynamically adjusted based on the Channel Access Priority Class (CAPC) value and current channel conditions, allowing the system to adapt to different transmission scenarios and optimize both collision avoidance and time efficiency.
2Reliability
If additional time gap is added for LBT operations, then collision probability reduces, but transmission efficiency decreases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the time gap parameter based on CAPC values and channel conditions. Instead of a fixed time gap, the system modifies the gap duration as a variable parameter that optimizes between collision avoidance and transmission efficiency for different priority classes and sensing scenarios.
Solution Approach 2:
The patent implements dynamics by making the time gap flexible rather than static. The gap is dynamically adjusted based on real-time channel conditions, CAPC values, and LBT sensing requirements, allowing the system to minimize unnecessary delays while ensuring sufficient time for collision avoidance when needed.
3Reliability
If resource re-evaluation process is implemented, then collision prevention improves, but processing complexity increases
Solution Approach 1:
The patent applies feedback by implementing a resource re-evaluation mechanism that uses channel state information and WiFi detection results to determine whether to proceed with allocated resources. The system receives feedback about current channel conditions and adjusts resource allocation decisions accordingly, improving collision prevention through informed decision-making.
Solution Approach 2:
The patent implements self-service by enabling the UE to autonomously perform resource re-evaluation and pre-emption decisions based on its own channel conditions and detection results. The UE independently determines whether to proceed with transmission or wait for re-allocation, reducing the need for complex centralized control while maintaining high collision prevention capability.
Data Source
AI summary
Systems and processes are described for resource allocation for new radio (NR) sidelink transmissions in an unlicensed spectru (NR-U). More specifically, the resource allocation is performed for mode 1 sidelink transmissions. The methods and systems include a time gap field that is configured to indicate a time gap between downlink control information (DCI) format 3_0 transmissions and Physical Sidelink Control Channel (PSCCH) or Physical Sidelink Shared Channel (PSSCH) transmissions.