PDCCH Time Slot Format for Unlicensed Spectrum Channel Notification
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Solution Overview
Problem
In 3GPP NR systems, base stations cannot effectively notify user equipment of channel occupation situations in unlicensed spectra, leading to inefficient channel sharing and reduced data transmission rates.
Innovation Solution
The method involves sending time slot format information through a Physical Downlink Control Channel (PDCCH) to notify user equipment of channel occupation, allowing for effective channel sharing and improved channel occupation rates by indicating occupied and release times within the channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base station sends time slot format information through PDCCH to notify channel occupation, then channel sharing efficiency is improved, but signaling overhead increases
Solution Approach 1:
The PDCCH message structure is designed to serve multiple purposes: it carries both time slot format information and channel occupation indication simultaneously. The same downlink control information (DCI) format is used for both slot format indication and channel access notification, making the signaling mechanism multi-functional and reducing overall overhead.
Solution Approach 2:
The channel occupation indication is nested within the existing time slot format indication framework. The base station embeds channel occupation information inside the PDCCH message that already carries slot format information, creating a nested information structure where one type of indication is contained within another without requiring separate signaling channels.
2Productivity
If base station notifies channel occupation information to UE, then channel occupation rate is improved, but system complexity increases
Solution Approach 1:
The UE autonomously determines channel occupation status by interpreting the time slot format information received from the base station. Instead of requiring the base station to send separate explicit occupation notifications, the UE self-services by deriving channel occupation details from the slot format indicators it already processes for scheduling decisions.
Solution Approach 2:
Instead of the base station actively notifying the UE about channel occupation, the approach is inverted: the base station sends slot format information that implicitly indicates occupation status, and the UE inverts this by deriving occupation information from the format indicators. The notification direction is reversed from explicit to implicit.
Data Source
AI summary
A method and a device for notifying channel occupation time, a base station and a user equipment. The method which applies to a base station includes: in an unlicensed spectrum, performing LBT and channel access; and when a channel is accessed successfully, sending a time slot format information which indicates one or more time slots of one or more cells to a UE through a PDCCH. The method which applies to a user equipment includes: in an unlicensed spectrum, receiving time slot format information, sent by a base station via a PDCCH after channel access is successfully completed, indicating one or more time slots of one or more cells; acquiring channel occupation information and channel release information according to the time slot format information; and according to the channel occupation information and the channel release information, performing downlink reception, uplink transmission or channel access in symbols of each time slot.