Unlicensed Band COT Indication for PDCCH Detection
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Solution Overview
Problem
In unlicensed bands, user equipment (UE) faces challenges in predicting when a base station can seize the channel and for how long, leading to high power consumption due to frequent physical downlink control channel (PDCCH) blind detection, as there is no cell-specific reference signal in New Radio (NR) and uncertainty about channel state.
Innovation Solution
A transmission time indication method where network devices listen to the channel state and indicate the remaining channel occupancy time (COT) when the channel is idle, allowing terminals to perform PDCCH blind detection within this specified time, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE performs frequent PDCCH blind detection to detect channel state and transmission opportunities, then the reliability of data reception is improved, but the power consumption of terminal increases
Solution Approach 1:
The base station performs channel listening and determines channel occupancy time in advance before actual data transmission. It then indicates this pre-determined COT information to the UE, allowing the UE to perform PDCCH blind detection only within the indicated COT window rather than continuously or at all possible positions, thereby reducing power consumption while maintaining reliable detection
Solution Approach 2:
The patent introduces dynamic COT indication where the base station adaptively determines and signals the channel occupancy time based on real-time channel conditions and transmission needs. The UE dynamically adjusts its detection strategy based on the received COT information, performing detection only during the indicated period rather than using fixed or continuous detection patterns
2Measurement precision
If UE performs PDCCH blind detection at every possible transmission starting position, then the detection accuracy is improved, but the detection complexity and processing overhead increase
Solution Approach 1:
The base station performs preliminary channel assessment and determines the channel occupancy time before transmission. By indicating this COT information in advance, it guides the UE to focus detection efforts only within the relevant time window, eliminating the need for exhaustive detection at all possible positions while maintaining detection accuracy
Solution Approach 2:
Instead of requiring the UE to perform detection at every single possible transmission position (excessive action), the patent applies partial action by limiting detection to only those positions within the indicated COT window. This partial detection approach is sufficient because the base station has already determined that no transmission will occur outside this window, making exhaustive detection unnecessary
Data Source
AI summary
Embodiments of the present disclosure provide a transmission time indication method for unlicensed band, a network device, and a terminal. The method includes: listening channel state; and when the channel state is idle, indicating first channel occupancy time (COT) information, where the first COT information is used to indicate a remaining COT of the network device.