TXOP with Continued LBT After Pause for Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE and 5G networks, face challenges in optimizing transmission opportunities (TXOP) due to the scarcity of licensed spectrum and the need for efficient use of unlicensed spectrum, where interruptions from other devices can lead to inefficient channel utilization.
Innovation Solution
The implementation of a TXOP with a pause mechanism that allows for continued listen-before-talk (LBT) after a pause, enabling the original user to reassess channel availability and resume transmission efficiently, thereby optimizing spectrum utilization and reducing interruptions from intervening devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pause is inserted in TXOP transmission, then channel availability can be reassessed and intervening transmissions can be detected, but transmission time is lost and channel occupancy is reduced
Solution Approach 1:
The LBT procedure is made dynamic by allowing it to continue across the pause boundary rather than resetting. The system adapts the channel access mechanism to accommodate interruptions while maintaining continuous channel assessment, enabling the transmitter to dynamically adjust to channel conditions after pauses without losing the original TXOP opportunity.
Solution Approach 2:
The LBT procedure maintains continuity by not resetting after a pause. The channel sensing action continues seamlessly from before the pause through after the pause, ensuring that the useful action of channel assessment remains uninterrupted despite the transmission pause, thereby preserving the original TXOP.
2Ease of operation
If LBT is reset after a pause, then channel sensing starts fresh, but the original TXOP may be lost to other devices
Solution Approach 1:
The LBT procedure is initiated before the pause occurs, establishing the channel access right in advance. This preliminary action allows the transmitter to secure the channel before the interruption, ensuring that when transmission resumes, the original TXOP is still valid and other devices cannot claim the channel.
Solution Approach 2:
The LBT procedure continues without resetting after the pause, maintaining the continuous useful action of channel sensing. This ensures that the original TXOP holder retains channel access rights throughout the pause period, preventing other devices from seizing the channel and maximizing spectrum utilization.
3Reliability
If continuous LBT is performed after pause, then channel occupancy can be maintained, but device complexity increases
Solution Approach 1:
The TXOP is segmented into multiple transmission portions separated by pauses, with LBT continuing across these segments. This segmentation allows the system to maintain channel occupancy through multiple discrete transmission opportunities while managing complexity by treating each portion as a separate but connected unit under the continuous LBT framework.
Data Source
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AI summary
Devices and methods of transmit opportunity (TXOP) with continued listen-before-talk (LBT) are generally described. A user equipment (UE) can be configured to perform a single LBT during an LBT scanning instance, to detect availability of an unlicensed wireless channel. Upon detecting availability of the channel, data is encoded for transmission during a TXOP with a TXOP duration. A pause in the transmission of the data is initiated upon expiration of a first time interval of the TXOP. A continuous LBT procedure is performed upon expiration of the pause, to determine a plurality of sensing metrics indicating occupancy of the unlicensed wireless channel. The transmission of the data is resumed during the TXOP for a second time interval, when at least one sensing metric of the plurality of sensing metrics is below a threshold.