HARQ-ACK PUCCH Resource Selection in CoMP DCI Scheduling
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Solution Overview
Problem
In coordinated multipoint transmission/reception (CoMP) scenarios, terminal devices face challenges in determining a physical uplink control channel (PUCCH) resource for hybrid automatic repeat request-acknowledgment (HARQ-ACK) feedback due to multiple downlink control information (DCI) signals from different network devices, leading to interference and unclear resource allocation.
Innovation Solution
A method to determine the PUCCH resource by identifying the last PDCCH monitoring occasion and using index values of a first parameter to indicate the target DCI, ensuring all HARQ-ACK feedback bits are carried on a unified PUCCH resource, thereby improving uplink transmission performance and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple DCI pieces are monitored on the same PDCCH monitoring occasion in CoMP systems, then the terminal device can receive scheduling information from multiple network devices, but the terminal device cannot determine which DCI's PUCCH resource indication should be used, leading to resource ambiguity and interference
Solution Approach 1:
Instead of trying to identify which DCI should be used among multiple DCI pieces, the patent inverts the approach by selecting the last monitored DCI in time domain as the target. This reversal of selection logic eliminates the ambiguity problem - rather than searching for the 'correct' DCI among multiple candidates, the system simply uses the most recently monitored DCI, making the selection deterministic and unambiguous.
Solution Approach 2:
The patent establishes a clear preliminary rule for DCI selection based on monitoring occasion timing. By pre-defining that the last monitored DCI shall be used, the terminal device has a predetermined criterion for resource determination, eliminating the need for complex real-time decision-making and ensuring consistent resource selection across different CoMP scenarios.
2Ease of operation
If the terminal device uses the existing mechanism of selecting PUCCH resource based on PDCCH monitoring occasion with largest number, then the mechanism is simple, but it fails to identify the correct DCI in CoMP scenarios, causing incorrect PUCCH resource usage
Solution Approach 1:
The patent changes the selection parameter from 'monitoring occasion with largest number' to 'last monitored DCI in time domain'. This parameter change maintains operational simplicity while dramatically improving identification accuracy in CoMP scenarios, as the time-based selection criterion naturally resolves the ambiguity of which DCI to use when multiple DCI pieces are present.
3Productivity
If multiple network devices separately indicate scheduling by using independent PDCCH, then each network device can independently control scheduling, but multiple PUCCH resource indications create conflict and interference in uplink transmission
Solution Approach 1:
The patent merges multiple PUCCH resource indications into a single effective indication by selecting only the last monitored DCI. This combining approach allows multiple network devices to maintain independent scheduling capabilities while ensuring that only one PUCCH resource indication is ultimately used, thereby eliminating uplink transmission interference caused by conflicting resource indications.
Data Source
AI summary
This application provides methods and apparatuses for determining a hybrid automatic repeat request-acknowledgment (HARQ-ACK) resource. One method includes: determining at least one physical downlink control channel (PDCCH) monitoring occasion, wherein HARQ-ACK feedback bits scheduled by using downlink control information (DCI) monitored on the at least one PDCCH monitoring occasion are carried on a same physical uplink control channel (PUCCH) resource; and determining, based on index values of a control-resource set group corresponding to first DCI, target DCI indicating the PUCCH resource, wherein the first DCI is on a last PDCCH monitoring occasion in the at least one PDCCH monitoring occasion, and wherein the control-resource set group comprises one or more control-resource sets.