Multi-Cell Beam Scheduling With TCI Mapping to Cut DCI Overhead
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Solution Overview
Problem
Existing 5G NR systems lack efficient multi-cell scheduling methods that reduce signaling overhead and maintain scheduling flexibility, particularly for joint scheduling of multiple PDSCHs or PUSCHs across multiple cells, leading to unnecessary control signaling overhead and inefficiencies.
Innovation Solution
Implement a multi-cell scheduling DCI (MC-DCI) format that allows for joint scheduling of multiple cells with reduced signaling overhead by using a single DCI format, where TCI states are determined based on most recent individual cell scheduling DCI (SC-DCI) states or configured reference states, and includes mechanisms for determining TCI states applicable to co-scheduled PDSCHs or PUSCHs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If individual cell scheduling DCI formats are used for each cell, then scheduling flexibility is maintained, but signaling overhead increases
Solution Approach 1:
The patent combines multiple individual cell scheduling DCI formats into a single multi-cell scheduling DCI format that can schedule PDSCHs across multiple cells simultaneously. This merging approach reduces the total number of DCI messages required while maintaining the ability to independently configure TCI states for each scheduled cell, thereby reducing signaling overhead without sacrificing scheduling flexibility.
Solution Approach 2:
The multi-cell scheduling DCI format is designed to perform multiple functions: it can schedule PDSCHs on multiple cells simultaneously, indicate TCI states for each scheduled cell, and support both intra-band and inter-band carrier aggregation. This universal format eliminates the need for separate DCI formats for different cell scheduling scenarios, reducing overall signaling overhead while preserving operational flexibility.
2Quantity of substance
If multi-cell scheduling DCI format is implemented, then signaling overhead is reduced, but determination of TCI states becomes more complex
Solution Approach 1:
The patent pre-configures TCI state mappings between codepoints and actual TCI states for each cell before multi-cell scheduling occurs. These preliminary configurations are stored in the UE, allowing the multi-cell scheduling DCI to simply indicate codepoints rather than full TCI state descriptions. This preliminary action simplifies the real-time determination process while maintaining accurate TCI state assignment across multiple cells.
Solution Approach 2:
The patent introduces codepoints as intermediary elements between the multi-cell scheduling DCI and the actual TCI states. Instead of directly managing complex TCI state assignments, the DCI format uses simplified codepoint indicators that map to pre-configured TCI states. This intermediary layer reduces the complexity of TCI state determination while preserving the ability to accurately configure multiple cells.
3Measurement precision
If TCI states are individually configured for each cell, then beamforming precision is maintained, but configuration complexity increases
Solution Approach 1:
The patent uses codepoints as simplified copies or references to actual TCI state configurations. Each codepoint in the multi-cell scheduling DCI represents a pre-configured TCI state mapping that can be reused across multiple cells. This copying approach maintains the precision of individual TCI state configurations while reducing the complexity of repeating full configurations for each cell.
Solution Approach 2:
The patent segments the TCI state configuration into two distinct layers: (1) pre-configured TCI state mappings associated with specific cells, and (2) dynamic codepoint indicators in the multi-cell scheduling DCI. This segmentation allows beamforming precision to be maintained through cell-specific TCI state configurations while reducing overall configuration complexity through the use of reusable codepoints.
Data Source
AI summary
Methods and apparatuses for multi-beam operation for multi-cell scheduling. A method includes receiving first information for a set of cells, second information for a set of transmission configuration indication (TCI) states associated with each cell in the set of cells, respectively, and a first physical downlink control channel (PDCCH) that provides a first DCI format. The first DCI format schedules receptions of first physical downlink shared channels (PDSCHs) on respective first cells from the set of cells. The first DCI format includes a first TCI field indicating a combination of TCI states that includes a number of TCI states that is equal to a number of cells in the set of cells. The method further includes determining first TCI states from the combination of TCI states and receiving the first PDSCHs, or second PDSCHs after the first PDSCHs, on the first cells based on the first TCI states, respectively.