Deferred PUCCH HARQ-ACK Timing for SPS Feedback Collisions
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Solution Overview
Problem
In wireless communication systems, particularly 5G NR, there is a need to address the issue of HARQ feedback collisions between semi-persistent scheduling (SPS) and downlink symbols, which can lead to inefficiencies and potential data loss.
Innovation Solution
A method and apparatus are provided to defer the transmission of SPS HARQ-ACK feedback when it overlaps with a downlink symbol, allowing it to be transmitted in a subsequent uplink symbol or dynamically scheduled PUCCH, based on a configured deferred feedback mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SPS HARQ-ACK feedback is transmitted according to the scheduled timing, then the feedback transmission is efficient and timely, but the transmission may collide with downlink symbols causing data loss
Solution Approach 1:
The patent applies dynamics by making the PUCCH transmission timing flexible rather than fixed. The UE dynamically adjusts the transmission timing based on the detected slot format, switching between dynamic scheduling mode (for flexibility) and semi-persistent scheduling mode (for efficiency). This dynamic adaptation resolves the contradiction by allowing timely feedback transmission while avoiding collisions with downlink symbols through real-time timing adjustment.
Solution Approach 2:
The patent changes the timing parameter of PUCCH transmission based on slot format detection. When a downlink-only slot is detected, the UE modifies the transmission parameter by deferring the PUCCH to a subsequent uplink slot. This parameter change resolves the contradiction by adapting the transmission time to avoid collisions while maintaining feedback reliability.
2Productivity
If the transmission timing is fixed for SPS HARQ-ACK feedback, then the system is simple to implement, but collisions with downlink symbols occur disrupting transmission efficiency
Solution Approach 1:
The system transitions from a static fixed timing approach to a dynamic timing approach. The UE monitors slot formats and dynamically adjusts PUCCH transmission timing accordingly. This dynamic mechanism resolves the contradiction by maintaining transmission efficiency through timely feedback while managing complexity through automated detection and adaptation based on predefined configurations.
Solution Approach 2:
The patent implements a feedback mechanism where the UE detects the actual slot format and provides feedback information to determine the appropriate transmission timing. This feedback loop resolves the contradiction by using detected slot format information to adjust timing, thereby maintaining efficiency while managing complexity through automated feedback-based decision making.
3Speed
If HARQ-ACK feedback is transmitted immediately without deferral, then the transmission speed is high, but collisions with downlink symbols cause data loss
Solution Approach 1:
The patent applies dynamics by enabling the system to adapt transmission timing based on detected slot formats. The UE dynamically decides whether to transmit immediately or defer based on whether the current slot is suitable for uplink transmission. This dynamic approach resolves the contradiction by maintaining high speed when possible while ensuring reliability by deferring when collisions would occur.
Solution Approach 2:
The patent implements preliminary action by having the UE detect the slot format in advance before transmission. The UE determines beforehand whether the scheduled transmission slot is suitable for uplink, and if not, prepares to defer the transmission to a subsequent uplink slot. This preliminary detection and preparation resolves the contradiction by preventing collisions before they occur while maintaining fast transmission when conditions permit.
Data Source
AI summary
Method and apparatus to defer transmission of HARQ-ACK feedback that overlaps a DL symbol. The apparatus determines to transmit PUCCH SPS HARQ-ACK feedback in response to a received semi-persistently scheduled PDSCH. The apparatus determines that the transmission of the SPS PUCCH HARQ-ACK feedback would overlap with a DL symbol. The transmission of the SPS PUCCH HARQ-ACK feedback is deferred to another UL symbol if the transmission of the SPS PUCCH HARQ-ACK feedback overlaps with the DL symbol. The apparatus transmits, based on the determination that the SPS PUCCH HARQ-ACK feedback would overlap with a DL symbol, a deferred SPS PUCCH HARQ-ACK feedback in one of a next set of available UL symbols or concurrently with a PUCCH HARQ-ACK feedback transmission in a next dynamically scheduled PUCCH after the DL symbol based on a deferred feedback configuration configured to define PUCCH content.