HARQ-ACK Timing for Multi-Cell Scheduling Across TDRA Tables
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Solution Overview
Problem
Legacy 5G NR systems face inefficiencies in multi-cell scheduling due to high signaling overhead and lack of support for joint scheduling of multiple PDSCHs or PUSCHs across cells, leading to repeated control signaling and increased CRC fields, especially in scenarios with multiple co-scheduled cells.
Innovation Solution
Implement methods for multi-cell scheduling using a single DCI format or two-stage DCI formats to reduce signaling overhead, including enhancements to Type-1 HARQ-ACK codebooks that account for different timing relationships and SCS configurations across cells, allowing joint scheduling with reduced signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate DCI formats are used for each cell in multi-cell scheduling, then each cell can be scheduled independently with full control flexibility, but signaling overhead increases due to repeated control signaling and increased CRC fields
Solution Approach 1:
The patent combines multiple cell scheduling into a single DCI format, merging the control signaling for multiple cells into one message. This reduces the quantity of control signaling transmitted over the air interface while maintaining the ability to schedule multiple cells independently through unified resource allocation fields and cell-specific indicators within the combined DCI structure.
Solution Approach 2:
The DCI format is designed with multi-functionality to handle both single-cell and multi-cell scheduling scenarios. The same DCI format structure can accommodate different numbers of cells through configurable fields, making it a universal solution that reduces overhead for multi-cell while preserving flexibility for single-cell operations.
2Quantity of substance
If joint scheduling of multiple PDSCHs or PUSCHs across cells is implemented, then signaling overhead is reduced, but complexity increases in handling different timing relationships and SCS configurations
Solution Approach 1:
The patent segments the joint scheduling approach by introducing separate TDRA tables for different cell groups or configurations. This allows the UE to handle timing relationships and SCS configurations in a structured manner, breaking down the complex joint scheduling into manageable segments that can be processed independently while maintaining overall coordination.
Solution Approach 2:
The patent introduces TDRA tables as an intermediary structure between the DCI format and the actual resource allocation. These tables pre-defined timing relationships and resource configurations, serving as a mediator that simplifies the processing of joint scheduling by providing lookup-based resource determination rather than requiring complex real-time calculations.
3Measurement precision
If Type-1 HARQ-ACK codebooks are enhanced to account for different timing relationships, then acknowledgment accuracy improves across cells with different SCS configurations, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring TDRA tables with all possible timing relationships and SCS configurations before actual data transmission. The UE uses these pre-computed tables to quickly determine the appropriate HARQ-ACK timing without performing complex real-time calculations, thus maintaining acknowledgment accuracy while reducing processing complexity during active communication.
Data Source
AI summary
Apparatuses and methods for acknowledgement information for multi-cell scheduling in a wireless communication system. A method of a user equipment (UE) includes receiving first information for a set of cells and second information for first time-domain resource allocation (TDRA) tables. The first TDRA tables correspond to respective first cells from the set of cells. An entry of a TDRA table from the first TDRA tables indicates a time resource for a physical downlink shared channel (PDSCH) reception on a cell from the first cells. The method further includes identifying a second TDRA table, determining acknowledgment information corresponding to the set of cells based on a union of rows of the first TDRA tables and the second TDRA table, and transmitting a physical uplink control channel (PUCCH) with the acknowledgment information. An entry of the second TDRA table indicates time resources for receptions of first PDSCHs on the set of cells.