SCell-to-PCell PDCCH Candidate Limits Across Different SCSs

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Solution Overview

Problem

In cross-carrier scheduling operations from a secondary cell (SCell) to a primary cell (PCell) in 5G NR, the processing capabilities of user equipment (UE) limit the number of physical downlink control channel (PDCCH) candidates that can be processed, necessitating a regulation of total PDCCH candidates based on UE processing capabilities.

Innovation Solution

The method involves monitoring and configuring PDCCHs on multiple component carriers (CCs) with different subcarrier spacings, ensuring that the total number of PDCCH candidates or non-overlapped control channel elements (CCEs) across CCs does not exceed a predefined budget, based on the lowest subcarrier spacing, and adhering to UE capability information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If cross-carrier scheduling is configured from SCell to PCell/PSCell with multiple scheduling cells, then the number of PDCCH candidates that can schedule data on PCell/PSCell increases, but the UE processing capabilities are exceeded

Engineering Contradiction:

Improvecross-carrier scheduling capabilityVSAvoidUE processing capability

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the number of PDCCH candidates based on UE processing capabilities. The network configures different numbers of PDCCH candidates for different scheduling cells (SCell and PCell/PSCell) depending on UE capability information, transforming a static configuration into an adaptive one that matches UE processing limits while maximizing scheduling flexibility.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system introduces dynamic configuration where the number of PDCCH candidates is not fixed but can be adjusted based on UE capability reporting. The network dynamically determines how many PDCCH candidates to configure for cross-carrier scheduling from SCell to PCell/PSCell, making the system adaptable to varying UE processing capabilities while maintaining scheduling versatility.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the total number of PDCCH candidates is increased to cover more scheduling options, then scheduling flexibility improves, but UE processing load increases

Engineering Contradiction:

Improvescheduling flexibilityVSAvoidUE processing load

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the parameter of PDCCH candidate numbers based on UE capability information. The network adjusts the number of PDCCH candidates configured for cross-carrier scheduling to match UE processing capabilities, preventing excessive processing load while maintaining sufficient scheduling flexibility for various data transmission scenarios.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system applies partial action by configuring only the necessary number of PDCCH candidates based on actual UE capability and scheduling needs, rather than providing maximum possible candidates. This ensures UE processing load remains manageable while still providing adequate scheduling options for data transmission on PCell/PSCell.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If different numerologies are used for SCell and PCell/PSCell, then spectrum utilization improves, but the PDCCH candidate budget becomes more complex to manage

Engineering Contradiction:

Improvespectrum utilizationVSAvoidPDCCH candidate budget management

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the PDCCH candidate budget management by treating SCell and PCell/PSCell scheduling separately with different candidate configurations. Instead of managing a unified budget across different numerologies, the system divides the candidate allocation into distinct portions for SCell cross-carrier scheduling and PCell/PSCell local scheduling, making complexity manageable while supporting different numerologies for optimized spectrum utilization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the parameter approach by configuring different numbers of PDCCH candidates for different numerologies and scheduling scenarios. The network adjusts candidate budgets based on the specific numerology combinations and UE capabilities, transforming the complex budget management into a set of manageable, scenario-specific configurations that support diverse numerologies.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12414123B2Number of BD and CCE for cross-carrier scheduling from an S-Cell to a P-Cell

Publication Date: 2025.09.09 QUALCOMM INC

AI summary

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for determining numbers of BDs and CCEs for cross-carrier scheduling from a SCell to a PCell/PSCell. A UE may concurrently monitor, on different component carriers, a first PDCCH and a second PDCCH having different SCSs. The PDCCHs may each be configured to schedule PDSCH or PUSCH on a same component carrier of the different component carriers. Each of the PDCCHs may be associated with a respective number of PDCCH candidates or a respective number of non-overlapped CCEs, the respective numbers further associated with respective maximum numbers based on the different SCSs. A first sum of the respective number of PDCCH candidates or a second sum of the non-overlapped CCEs may be less than or equal to N times the lower of the respective maximum numbers.