Unlicensed Spectrum Data Transmission Timing
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Solution Overview
Problem
Current data transmission methods on unlicensed spectra in 5G NR systems face challenges due to variable subframe lengths and lack of solutions for efficient data transmission, leading to unpredictable start times and reduced channel utilization.
Innovation Solution
A data transmission method that performs Listen Before Talk (LBT) on unlicensed spectra, allowing data to be sent at a second moment within a pre-configured subframe structure, which can be either consecutive or non-consecutive, to align with a reference subframe, thereby shortening the waiting time from LBT to data transmission and improving channel utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT is performed before data transmission on unlicensed spectrum, then collision avoidance is achieved, but data transmission start time becomes unpredictable
Solution Approach 1:
The patent applies preliminary action by performing LBT operation before data transmission to check channel availability. The transmit end performs LBT at a first moment, and if the channel is idle, data transmission starts at a second moment within the same subframe, ensuring collision avoidance while enabling flexible timing within the subframe structure.
Solution Approach 2:
The patent applies dynamics by allowing the data transmission start time to be flexible within a subframe rather than fixed at subframe boundaries. The second moment for data transmission can occur at any valid start point within the subframe, making the system adaptive to channel conditions while maintaining structured timing through subframe configurations.
2Stability of the object's composition
If data transmission starts only at subframe or slot boundaries in LTE/LTE-A, then timing alignment is maintained, but channel utilization decreases
Solution Approach 1:
The patent applies segmentation by dividing the subframe into multiple possible data transmission start points. Instead of allowing transmission only at subframe or slot boundaries, the patent enables data transmission to start at multiple valid points within the subframe, including intermediate positions, thereby increasing channel access opportunities while maintaining subframe structure for timing alignment.
Solution Approach 2:
The patent merges the benefits of fixed timing alignment with flexible channel access by combining subframe-based timing structure with multiple valid data transmission start points within each subframe. This allows the system to maintain timing synchronization through subframe boundaries while enabling data transmission at various points within the subframe to improve channel utilization.
3Adaptability or versatility
If variable subframe lengths are used in 5G NR, then adaptability to different services is improved, but system complexity increases
Solution Approach 1:
The patent applies parameter changes by utilizing variable subframe lengths in 5G NR to adapt to different service requirements. Different subframe configurations (e.g., different numbers of OFDM symbols) are used based on service type, allowing flexible adaptation while maintaining a unified frame structure. The patent handles these variable parameters through consistent LBT and data transmission procedures regardless of subframe length.
Data Source
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Figure 3A
Figure 3B~4B
AI summary
The present invention discloses a data transmission method on an unlicensed spectrum, and a device. The method includes: performing, by a transmit end, an LBT operation on an unlicensed spectrum; and if determining at a first moment that the unlicensed spectrum is idle and available, sending data to a receive end at a second moment by using the unlicensed spectrum, where the second moment is greater than or equal to the first moment and is less than or equal to a third moment, the third moment is a start moment of a reference subframe after the first moment, a length of the reference subframe is the same as a length of one of at least two types of pre-configured subframes, and adjacent reference subframes are consecutive in terms of time. Therefore, when a plurality of subframes with different lengths are configured, data sending and receiving on the unlicensed spectrum is implemented. The second moment is greater than or equal to the first moment and is less than or equal to the third moment, and the third moment is the start moment of the reference subframe after the first moment, thereby shortening a waiting time from LBT to a start moment of data transmission, and improving channel utilization.