Scheduled-Resource Sensing for Unlicensed-Band Uplink
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Solution Overview
Problem
In 5G mobile communications systems operating in unlicensed bands, the uncertainty of channel availability due to contention-based access modes and LBT failures leads to inefficient uplink data transmission, resulting in punctured data and reduced transmission efficiency.
Innovation Solution
A method and terminal for uplink transmission in unlicensed bands that involve sensing scheduled resources to obtain sensing results and transmitting transport blocks based on these results, with network devices adjusting scheduling parameters or terminals autonomously adapting transmission parameters to ensure data is transmitted only on available subbands, reducing puncturing and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT category 3 with random backoff is used for channel sensing, then channel access reliability is improved, but transmission delay increases and transmission efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the LBT category selection adaptive rather than fixed. The terminal dynamically chooses between LBT Cat 1, 2, or 3 based on real-time channel conditions and network configuration, allowing the system to optimize between reliability and delay depending on the situation. This is implemented through receiving LBT parameter configuration from the network and selecting appropriate LBT categories for different transmission scenarios.
Solution Approach 2:
The patent changes the parameter of LBT category selection from a static choice to a dynamic parameter that can be adjusted based on channel conditions, transmission priority, and network configuration. By varying which LBT category is used (Cat 1 for immediate transmission, Cat 2 for 25us sensing, or Cat 3 for random backoff), the system adapts the sensing behavior to balance reliability and delay requirements.
2Productivity
If multiple consecutive slots are scheduled for continuous transmission, then transmission efficiency is improved, but puncturing risk increases when LBT fails
Solution Approach 1:
The patent segments the scheduled transmission slots into multiple LBT opportunities, allowing the terminal to perform LBT sensing at different points within the scheduled resources. Instead of attempting transmission across all consecutive slots without interruption, the terminal can segment the transmission and perform LBT at designated positions, reducing the impact of LBT failure on the entire transmission.
Solution Approach 2:
The patent applies preliminary action by performing LBT sensing before each transmission attempt or at specific positions within scheduled slots. This advance sensing allows the terminal to prepare transmission data and determine channel availability beforehand, reducing the risk of puncturing by identifying unavailable channels before committing to transmission across multiple consecutive slots.
3Reliability
If LBT is performed in each 20 MHz subband before wideband transmission, then channel access reliability is improved, but transmission preparation complexity increases
Solution Approach 1:
The patent segments the wideband channel into multiple 20 MHz subbands and performs LBT sensing independently on each subband. This segmentation allows the terminal to identify which specific subbands are available for transmission, reducing the complexity compared to performing LBT on the entire wideband channel as a single unit. The terminal can then prepare transmission only for available subbands.
Solution Approach 2:
The patent applies local quality by allowing different LBT outcomes for different subbands within the same wideband channel. Instead of treating all subbands uniformly, the system recognizes that each subband may have different availability conditions and prepares transmission accordingly, with each subband having its own transmission parameters based on its LBT result.
4Reliability
If data is punctured when LBT fails on certain subbands, then transmission on available subbands is maintained, but overall transmission efficiency deteriorates
Solution Approach 1:
The patent makes the transmission parameters dynamic based on LBT results. When LBT succeeds on only some subbands, the terminal dynamically adjusts transmission parameters such as bandwidth, modulation scheme, and coding rate to match the actually available resources. This dynamic adaptation prevents wasting transmission opportunities on unavailable subbands while maximizing utilization of available subbands.
Solution Approach 2:
The patent implements feedback by using LBT sensing results to determine subsequent transmission parameters. The terminal feeds back the LBT outcome information to adjust the transmission strategy, selecting appropriate modulation and coding schemes based on the actual channel availability. This feedback mechanism ensures that transmission is optimized for the currently available subbands rather than using fixed parameters that assume full bandwidth availability.
Data Source
AI summary
This disclosure discloses a method for uplink transmission in an unlicensed band, a terminal, and a network device. The method includes: sensing a scheduled resource to obtain a corresponding sensing result; and transmitting a transport block on the scheduled resource based on the sensing result.