One-Shot HARQ Feedback Multiplexing in Shared Spectrum
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Solution Overview
Problem
Wireless communication systems in shared radio frequency spectrum face challenges in providing effective acknowledgment feedback, particularly in unlicensed bands, where interference from hidden nodes or listen-before-talk failures can lead to incomplete or missing HARQ feedback, affecting system performance.
Innovation Solution
The implementation of group or one-shot HARQ feedback reporting techniques, where user equipment (UE) provides feedback for multiple downlink transmissions, with the base station triggering a subset of feedback reports, including ACK/NACK indications and data indicators, to enhance efficiency and reliability, and multiplexing regular and one-shot feedback reports to reduce overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional individual HARQ feedback reporting is used for each downlink transmission, then feedback reliability for each transmission is maintained, but feedback overhead and system complexity increase significantly
Solution Approach 1:
The patent combines multiple individual HARQ feedback reports into a single group feedback report that includes ACK/NACK indications for multiple downlink transmissions. This merging approach reduces the number of separate feedback transmissions while maintaining comprehensive feedback coverage through the group feedback structure that can accommodate multiple transport blocks and code block groups.
Solution Approach 2:
The feedback report is segmented into different components: ACK/NACK indications for transport blocks, code block group feedback, and new data indicators. This segmentation allows the system to handle multiple transmission types within a single feedback report while maintaining organized and manageable feedback information structure.
2Productivity
If one-shot feedback reporting for multiple downlink transmissions is implemented, then feedback reporting efficiency improves, but the complexity of feedback processing and interpretation increases
Solution Approach 1:
The patent implements feedback mechanisms where the base station provides feedback indications to the UE about which downlink transmissions were successfully received and which require retransmission. This feedback loop enables efficient one-shot reporting while the base station processes the feedback to determine appropriate retransmission strategies.
Solution Approach 2:
The system pre-configures feedback reporting parameters and timelines before actual feedback transmission occurs. The base station and UE agree on feedback timing and structure in advance, which simplifies the actual feedback processing during operation by eliminating the need for real-time configuration decisions.
3Reliability
If comprehensive feedback for all downlink transmissions is provided, then system reliability is improved, but the time required for feedback transmission and processing increases
Solution Approach 1:
Multiple feedback items are merged into a single feedback report transmission, reducing the total time spent on feedback communication. The group feedback report structure allows simultaneous transmission of ACK/NACK information for multiple transport blocks and code block group feedback in one consolidated message.
Solution Approach 2:
The patent implements periodic feedback reporting where the UE transmits feedback at scheduled intervals rather than continuously. This periodic action allows comprehensive feedback to be provided at optimal times while minimizing transmission time by consolidating multiple feedback opportunities into coordinated reporting cycles.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described that provide for group or one-shot acknowledgment (ACK) feedback reporting, in which feedback for a number of different downlink transmissions may be provided by a user equipment (UE) to a base station. A base station may trigger a one-shot feedback report that includes less than all of the ACK feedback that is available at the UE to provide in a report. The ACK feedback may include an indication of an ACK or a negative acknowledgement (NACK) along with information related to a data indicator associated with the downlink transmission. In some cases regular ACK feedback reports and one-shot feedback reports may be multiplexed and transmitted by a UE. Further, a last downlink transmission to be included in a one-shot feedback report may be determined based on a receipt time of scheduling information or an ACK feedback timeline.