Sidelink HARQ Buffer Management for NR V2X Mode Switching
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Solution Overview
Problem
The existing NR V2X communication systems lack defined HARQ operation and buffer management protocols for sidelink transmissions, particularly in the presence of protocol errors and mode switching, which affects efficient resource allocation and communication reliability.
Innovation Solution
Implement methods for efficient sidelink HARQ protocol operation in NR V2X communication, including timer-based buffer management, QoS priority-based soft buffer handling, and DCI-induced flushing, to manage HARQ processes effectively across different resource allocation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback signaling is supported for sidelink transmission in NR V2X, then communication reliability is improved, but device complexity increases due to undefined UE behavior for HARQ protocol operation
Solution Approach 1:
The patent applies parameter changes by configuring HARQ process parameters including process ID, feedback timing, and retransmission parameters dynamically. The UE behavior is standardized through specific parameter configurations for HARQ feedback signaling, allowing reliable communication while maintaining manageable device complexity through systematic parameter management.
Solution Approach 2:
The patent implements feedback mechanisms where UEs send HARQ acknowledgments (ACK/NACK) for received transport blocks. The feedback timing and process are standardized, enabling the transmitting UE to determine whether retransmission is needed based on received feedback, thereby improving communication reliability through structured feedback loops.
2Reliability
If HARQ retransmissions are implemented for sidelink, then data transmission reliability is improved, but resource allocation efficiency deteriorates due to buffer management challenges
Solution Approach 1:
The patent applies preliminary action by pre-configuring HARQ buffer parameters and retransmission resources before actual data transmission. The UE is prepared with standardized buffer management procedures and retransmission parameters in advance, enabling efficient resource allocation during retransmission without compromising reliability.
Solution Approach 2:
The patent implements dynamic buffer management where the HARQ buffer size and retransmission parameters are adapted based on channel conditions and traffic requirements. The system dynamically adjusts resource allocation for retransmissions while maintaining standardized UE behavior, balancing reliability improvement with resource allocation efficiency.
3Adaptability or versatility
If UE-scheduled V2X communication mode is used, then resource allocation flexibility is improved, but scheduling accuracy deteriorates due to lack of centralized control
Solution Approach 1:
The patent applies self-service by enabling UEs to autonomously perform scheduling decisions in Mode-2 and Mode-4 operations. Each UE independently manages its own resource allocation based on standardized HARQ feedback mechanisms and buffer status reporting, achieving flexible resource allocation while maintaining scheduling accuracy through self-organized coordination.
Solution Approach 2:
The patent implements multi-functionality by designing a universal HARQ feedback mechanism that operates across different V2X modes (Mode-1 through Mode-4). The standardized UE behavior for HARQ protocol operation provides consistent feedback and buffer management across centralized and distributed scheduling modes, enabling both flexibility and accuracy.
4Device complexity
If blind retransmission without HARQ feedback is used, then device complexity is reduced, but communication efficiency deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where UEs send HARQ acknowledgments (ACK/NACK) for received transport blocks. The feedback timing and process are standardized, enabling the transmitting UE to determine whether retransmission is needed based on received feedback, thereby improving communication efficiency while maintaining manageable device complexity through structured feedback loops.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for scheduling a sidelink transmission. One apparatus includes a processor and a transceiver that receives a TB on SL resources, where the TB is associated with a SL HARQ process. The processor stores the TB in a HARQ soft buffer and makes available the HARQ soft buffer for new data in response to a predefined trigger.