Terminal and Base Station PUCCH Timing for HARQ-ACK Feedback
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Solution Overview
Problem
Existing communication systems in 5G-NR face challenges in efficiently managing HARQ-ACK feedback due to complexities in PUCCH resource determination and SPS release, which affect latency and reliability in scenarios like eMBB, mMTC, and URLLC.
Innovation Solution
A terminal apparatus and base station apparatus are designed to efficiently manage HARQ-ACK feedback by optimizing PUCCH resource allocation and SPS release through specific configurations of subcarrier spacing, resource grids, and control channel monitoring, utilizing QCL antenna ports and dedicated RRC signaling for carrier bandwidth parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PUCCH resource determination is performed using existing methods in 5G-NR, then HARQ-ACK feedback can be transmitted, but the process becomes complex and affects latency and reliability
Solution Approach 1:
The patent changes the parameter used for PUCCH resource determination from the lowest eCCE index to the lowest CCE index of the corresponding PDCCH. This parameter substitution simplifies the resource determination process while maintaining the association between downlink control channels and uplink feedback channels, thereby reducing complexity without compromising reliability.
Solution Approach 2:
The patent creates a universal PUCCH resource determination method that works across different scenarios (ePDCCH-scheduled PDSCH, ePDCCH-indicated SPS release, and PDCCH-indicated SPS release). By using the lowest CCE index as a common reference point, the system achieves multi-functionality in resource allocation without requiring scenario-specific complex procedures.
2Productivity
If multiple downlink subframes are associated with a single uplink subframe for HARQ-ACK feedback, then more data can be acknowledged, but the resource allocation becomes more complex
Solution Approach 1:
The patent introduces a new parameter relationship where the PUCCH resource index is directly derived from the lowest CCE index of the PDCCH rather than from eCCE indices. This simplifies the mapping between multiple downlink subframes and the uplink subframe, as each PDCCH's lowest CCE index independently identifies its corresponding PUCCH resource, reducing allocation complexity while maintaining multi-subframe feedback capability.
3Stability of the object's composition
If sequential allocation of PUCCH resources is performed for multiple downlink subframes, then resource organization is improved, but latency increases
Solution Approach 1:
The patent establishes preliminary PUCCH resource associations by linking each PUCCH resource to the lowest CCE index of its corresponding PDCCH before actual feedback transmission. This pre-configuration allows the terminal to quickly identify the correct PUCCH resource without sequential searching or complex allocation procedures during the feedback moment, thereby maintaining organized resource structure while reducing latency.
Data Source
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AI summary
An apparatus includes a receiver configured to receive a PDCCH including a DCI format, and a transmitter configured to transmit a PUCCH, wherein in a case that the DCI format schedules a PDSCH and that a last OFDM symbol of the PDSCH is mapped in a first slot, the PUCCH is transmitted in a second slot, and a first offset from the first slot to the second slot is given at least based on a PDSCH-to-HARQ-timing-indicator included in the DCI format, and in a case that the DCI format indicates an SPS release and that a last OFDM symbol of the PDCCH is mapped to a third slot, the PUCCH is transmitted in a fourth slot, and a second offset from the third slot to the fourth slot is given at least based on the PDSCH-to-HARQ-timing-indicator.