NR-U LBT Timing With Variable Cyclic Prefix Extensions
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Solution Overview
Problem
Existing communication technologies face issues such as gNB overriding, potential collisions between scheduled and configured grant physical uplink shared channel (CG-PUSCH) transmissions, and inefficiencies in LBT processes, particularly in 5G New Radio (NR-U) unlicensed spectrum, which affect channel access success and network performance.
Innovation Solution
Determine the duration of a gap between the end point of a first transmission and the start point of a cyclic prefix extension for a second transmission, and perform an LBT process based on comparisons with threshold durations for different LBT types, considering timing advance and channel occupancy conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terminal devices perform LBT operation immediately prior to transmissions with variable duration CP extension, then collision avoidance is improved, but channel access efficiency deteriorates due to blocking by earlier transmitters
Solution Approach 1:
The patent applies dynamics by making the CP extension duration variable rather than fixed. Different terminal devices can select different CP extension durations from a set of possible values, allowing the system to adaptively adjust the reservation signal length based on transmission timing and LBT requirements. This dynamic adjustment enables earlier transmitters to use longer CP extensions for reliable collision avoidance while allowing later transmitters to use shorter extensions, thereby improving overall channel access efficiency.
Solution Approach 2:
The patent changes the parameter of CP extension duration from a fixed value to a variable parameter that can be selected from multiple possible durations. This parameter change allows the system to optimize the balance between collision avoidance and channel access efficiency by matching the CP extension length to the specific transmission scenario and LBT timing requirements.
2Device complexity
If fixed CP extension duration is used for all terminal devices, then implementation complexity is reduced, but collision avoidance performance deteriorates in unlicensed spectrum
Solution Approach 1:
The patent segments the CP extension duration into multiple discrete possible values rather than using a single fixed duration. This segmentation allows the system to select from a set of predefined duration options (e.g., different time lengths) that are suited to different transmission scenarios, improving collision avoidance performance while maintaining relatively simple implementation through predefined choices.
Solution Approach 2:
The patent introduces dynamic selection of CP extension duration from a set of possible values based on transmission timing and LBT requirements. This dynamic approach allows each terminal device to adapt the CP extension length to its specific transmission scenario, improving collision avoidance performance without requiring complex real-time calculations, thus balancing implementation complexity with reliability.
3Reliability
If CP extension acts as reservation signal to block later transmitters, then collision avoidance is improved, but LBT process efficiency deteriorates due to unnecessary blocking
Solution Approach 1:
The patent applies dynamics by making the CP extension duration variable and adaptable to transmission timing. Later terminal devices can use shorter CP extensions when transmitting after earlier devices, reducing the reservation signal duration and thereby minimizing unnecessary blocking time. This dynamic adjustment allows the system to maintain collision avoidance reliability while reducing LBT process time and improving overall efficiency.
Solution Approach 2:
The patent changes the parameter of CP extension duration from a fixed long duration to a variable duration that can be optimized for each transmission scenario. This parameter change allows the system to reduce the reservation signal length when appropriate, minimizing the time lost during LBT processes while maintaining sufficient collision avoidance protection.
Data Source
AI summary
Example embodiments of the present disclosure relate to a solution for performing an operation related to a listen-before-talk (LBT) process for a transmission. In an aspect, an apparatus determines a duration of a gap between an end point of a first transmission to be transmitted by a further apparatus and a start point of a cyclic prefix extension prior to a second transmission to be transmitted by the apparatus. The apparatus performs an operation related to an LBT process for the second transmission based on comparisons between the duration of the gap and a plurality of threshold durations associated with a plurality of types of LBT processes. Example embodiments of the present disclosure can increase or even maximize the likelihood of the success of LBT processes.