UE Uplink Behavior Pattern for SFI-Free Channel Access
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Solution Overview
Problem
Uplink transmission efficiency is reduced in user equipment (UE) due to the inability to preempt the channel when no slot format indicator (SFI) PDCCH is detected, as base stations in unlicensed bands require clear channel detection before transmitting SFI PDCCH, leading to reduced uplink transmission opportunities.
Innovation Solution
The UE determines a terminal behavior pattern based on configuration information, downlink control information, and the licensed or unlicensed status of serving cells to adjust uplink transmission modes, allowing for configured or dynamic scheduled transmissions based on clear channel assessment results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station performs clear channel detection before transmitting SFI PDCCH in unlicensed bands, then the base station can transmit only when the channel is clear, but the UE cannot transmit configured uplink transmission when no SFI PDCCH is detected, reducing uplink transmission efficiency
Solution Approach 1:
The base station performs clear channel detection (LBT/CCA) in advance before transmitting SFI PDCCH to ensure channel availability. This preliminary action prevents transmission conflicts but creates a dependency where UE must wait for SFI PDCCH confirmation before uplink transmission, thus resolving the contradiction between reliable channel access and transmission efficiency by establishing a predictable transmission pattern
Solution Approach 2:
The UE autonomously determines its transmission behavior based on whether SFI PDCCH is detected and whether the channel is clear. When SFI PDCCH is not detected, the UE can still perform LBT and transmit configured uplink transmissions if the channel is clear, enabling self-service transmission without waiting for base station confirmation, thereby improving uplink transmission efficiency while maintaining channel access reliability
2Stability of the object's composition
If the UE waits for SFI PDCCH detection before transmitting configured uplink transmission, then channel access is coordinated, but transmission occasions are reduced and uplink transmission efficiency decreases
Solution Approach 1:
The UE dynamically adjusts its transmission behavior based on real-time channel conditions and SFI PDCCH detection results. Instead of following a fixed transmission pattern, the UE can switch between waiting for SFI PDCCH and performing autonomous LBT-based transmission, creating a dynamic transmission strategy that maintains coordination stability while improving transmission efficiency through adaptive opportunistic access
3Reliability
If the base station cannot transmit SFI PDCCH when the channel is busy, then clear channel detection is maintained, but UE uplink transmission opportunities are lost
Solution Approach 1:
The clear channel detection mechanism acts as an intermediary between the base station's SFI PDCCH transmission and the UE's uplink transmission. When the base station cannot transmit SFI PDCCH due to busy channel, the intermediary LBT mechanism at the UE side enables direct transmission decision-making, allowing UE to access the channel independently when clear, thus reducing transmission delay while maintaining detection reliability through the intermediary LBT process
Data Source
AI summary
This application provides an uplink transmission method and a terminal. The uplink transmission method includes: determining, based on at least one of the following, a terminal behavior pattern: configuration information of the terminal, received downlink control information, whether a serving cell in which first information is located is a licensed band, and whether a serving cell in which a first uplink transmission is located is a licensed band; and performing an uplink transmission based on the terminal behavior pattern.