COT Structure Indication for Accurate Subband LBT Updates
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Solution Overview
Problem
In wireless communication systems, particularly in shared or unlicensed spectrum, there is a challenge in accurately indicating the structure and duration of a channel occupancy time (COT) due to independent LBT procedures in each subband, leading to potential inaccuracies in initial COT indicators and inefficient communication signaling.
Innovation Solution
The technique involves a base station (BS) transmitting a first COT indicator indicating unknown subband usage, followed by subsequent updates to provide accurate subband usage information, and optimizing the representation of COT duration to reduce the number of bits required for indicating the remaining duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transmitting node transmits a preamble to reserve a channel occupancy time (COT) in the shared channel, then the transmitting node can communicate with a receiving node during the COT, but the initial COT indicator may be inaccurate due to independent LBT procedures in each subband
Solution Approach 1:
The base station performs LBT procedures in each subband before transmitting the COT indicator, and provides initial COT indication based on the LBT results. This preliminary action ensures that the COT indicator accurately reflects the actual channel availability in each subband, resolving the contradiction between reliability and time loss by preparing the channel status information in advance.
Solution Approach 2:
The system implements a feedback mechanism where the base station monitors LBT results during the COT period and provides update indicators to UEs when channel status changes. This feedback ensures continuous accuracy of COT information while minimizing time loss by only updating when necessary, rather than continuously monitoring and reporting.
2Reliability
If the base station provides frequent updates on subband usage information, then the accuracy of COT information is maintained, but the signaling overhead increases
Solution Approach 1:
The base station provides COT subband usage information periodically at specific intervals during the COT period, rather than continuously or at every channel status change. This periodic updating maintains sufficient accuracy for UE operations while significantly reducing signaling overhead compared to frequent updates, resolving the contradiction between reliability and information loss.
Solution Approach 2:
The system changes the updating parameter from frequent/continuous updates to periodic updates at optimized intervals. This parameter change in the updating frequency maintains the essential accuracy of subband usage information for UE LBT procedures while reducing the signaling overhead to acceptable levels.
3Device complexity
If the base station uses standard COT indication methods, then the implementation is straightforward, but the number of bits required for indicating remaining COT duration is large
Solution Approach 1:
The base station segments the COT duration indication into multiple parts: a maximum COT duration parameter configured via higher-layer signaling, and a remaining COT indicator using fewer bits that indicates the portion of COT remaining. This segmentation reduces the total bits required for indication while maintaining full precision, resolving the contradiction between device complexity and information loss.
Solution Approach 2:
Instead of indicating the complete COT duration from the beginning, the system uses partial indication by configuring the maximum COT duration in advance through higher-layer signaling and only indicating the remaining portion during operation. This partial indication approach significantly reduces the number of bits required while maintaining full functionality.
Data Source
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AI summary
Wireless communications systems and methods related to communicating a structure of a channel occupancy time (COT) are provided. A first wireless communication device communicates with a second wireless communication device, a first indicator indicating at least one of a subband configuration for a COT or a duration of the COT. The first wireless communication device communicates with the second wireless communication device during the COT, a first communication signal based on at least one of the subband configuration for the COT or the duration of the COT. The first wireless communication device communicates with the second wireless communication device during the COT, a second indicator indicating an update for at least one of the subband configuration for the COT or the duration of the COT. Additionally, the first wireless communication device communicates with the second wireless communication device during the COT, a second communication signal based on the update.