Multi-Cell HARQ-ACK Feedback on Shared PUCCH Resources
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Solution Overview
Problem
The capacity of NR PDCCHs is affected in carriers where LTE and NR coexist due to the inability to use resources where LTE cell reference signals and physical uplink control channels are located, necessitating a new mechanism to address this capacity issue in dynamic spectrum sharing.
Innovation Solution
A method for uplink transmission where a terminal device receives DCI to schedule PDSCHs of multiple serving cells and transmits HARQ-ACK information on a first PUCCH resource, with PUCCH groups defined by PUCCH cell parameters, allowing HARQ-ACK information to be fed back on a configured PUCCH secondary cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DCI schedules PDSCHs of multiple serving cells separately, then each cell can be managed independently, but DCI overhead increases and PUCCH resource utilization decreases
Solution Approach 1:
The patent combines multiple PDSCH scheduling operations into a single DCI message. The DCI includes a serving cell indicator field that identifies which serving cell the PDSCH belongs to, allowing one DCI to schedule PDSCHs across multiple serving cells. This merging approach reduces the number of separate DCI messages needed, thereby reducing DCI overhead while maintaining the ability to independently manage each serving cell through the indicator field.
2Reliability
If HARQ-ACK feedback is transmitted on separate PUCCH resources for each serving cell, then each cell's feedback is independent, but PUCCH resource utilization is inefficient
Solution Approach 1:
The patent enables multiple HARQ-ACK feedback bits corresponding to PDSCHs on different serving cells to be transmitted on a single PUCCH resource. The terminal device collects HARQ-ACK information for multiple serving cells and multiplexes them into one PUCCH transmission. This approach improves PUCCH resource utilization by consolidating feedback transmissions while maintaining reliability through proper multiplexing of the feedback bits.
3Reliability
If resources where LTE CRS and PDCCH are located are avoided for NR transmission, then LTE interference is prevented, but NR PDCCH capacity is reduced
Solution Approach 1:
The patent implements a multi-function DCI structure that can schedule PDSCHs across multiple serving cells including both LTE and NR cells. By including a serving cell indicator field in the DCI, the system can dynamically allocate resources across different cell types without requiring separate DCI formats for each cell type. This universality allows efficient utilization of available NR PDCCH capacity while respecting LTE resource constraints through proper cell identification and resource management.
Data Source
AI summary
A method for uplink transmission, a terminal device, and a network device are provided. The method includes the following. A terminal device receives a downlink control information (DCI) from a network device, where the DCI is used to schedule physical downlink shared channels (PDSCHs) of at least two serving cells. The terminal device transmits hybrid automatic repeat request (HARD)-acknowledgement (ACK) information corresponding to the PDSCHs of the at least two serving cells on a first physical uplink control channel (PUCCH) resource.