Downlink Control Information Sizing for Dormant Secondary Cells
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Solution Overview
Problem
In the New Radio (NR) communication system, when a secondary cell (SCell) is deactivated or its active downlink bandwidth part (BWP) is dormant, determining the size of downlink control information (DCI) for scheduling data transmission in the primary cell (PCell) is challenging due to the absence of PDCCH scheduling, leading to inefficiencies in information transmission performance.
Innovation Solution
A method is provided to accurately determine the size of DCI for scheduling data transmission in the PCell by re-making the DCI size determination rule when the SCell is deactivated or its BWP is dormant, using a corresponding non-dormant BWP within or outside active time, based on specific DCI formats and BWP configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the SCell is deactivated or its active BWP is dormant, then power consumption is reduced and resource utilization is optimized, but the ability to determine DCI size for scheduling PCell data transmission deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple BWPs (including dormant and non-dormant BWPs) before the SCell is deactivated. When deactivation occurs, the terminal can immediately reference the pre-configured non-dormant BWP parameters to determine DCI size, avoiding the need for real-time configuration and ensuring continuous ability to determine DCI size even when the active BWP becomes dormant.
Solution Approach 2:
The patent introduces a non-dormant BWP as an intermediary reference when the active BWP is dormant. This intermediary BWP serves as a bridge, allowing the terminal to determine DCI size by referencing the non-dormant BWP's parameters (such as bandwidth, subcarrier spacing) rather than directly using the dormant BWP, thus resolving the contradiction between power saving and DCI size determination capability.
2Productivity
If the SCell is deactivated or its active BWP is dormant, then resource allocation efficiency is improved, but information transmission performance deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting which BWP parameters are used for DCI size determination based on the activation state. When the SCell is active with a non-dormant BWP, those parameters are used directly. When deactivated or dormant, the system switches to using parameters from a pre-configured non-dormant BWP, ensuring reliable DCI size determination while maintaining resource allocation efficiency.
3Adaptability or versatility
If DCI size alignment between PCell and SCell is maintained, then scheduling flexibility is improved, but system complexity increases when SCell state changes
Solution Approach 1:
The patent applies copying by creating a reference copy of non-dormant BWP parameters that can be reused when the active BWP becomes dormant. Instead of maintaining complex real-time synchronization between PCell and SCell DCI sizes, the terminal copies the DCI size determination methodology from the non-dormant BWP configuration, simplifying the system while maintaining alignment capability.
Data Source
AI summary
This application provides a downlink control information transmission method and an apparatus. The method includes: A terminal determines a quantity of information bits of first downlink control information DCI based on a 1st corresponding non-dormant bandwidth part BWP of a secondary cell SCell within active time or a 1st corresponding non-dormant BWP of a secondary cell outside active time, and monitors the first DCI on a PDCCH candidate of a primary cell PCell based on the quantity of information bits of the first DCI. The first DCI is used to schedule data transmission of the PCell and/or data transmission of the SCell. The solutions disclosed in this application help accurately determine a size of DCI, and improve information transmission performance.