Directional LBT ED Threshold for 5G Unlicensed Band
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Solution Overview
Problem
In the context of 5G wireless communication systems, particularly in the unlicensed band, there is a challenge in effectively transmitting and receiving signals due to high path-loss in frequency bands above 52.6 GHz, which affects the reliability and efficiency of Listen-Before-Talk (LBT) operations, leading to potential interference with other radio access technologies (RATs).
Innovation Solution
The method involves determining an appropriate Energy Detection (ED) threshold for Directional LBT using technologies like analog beamforming with multiple antennas, allowing for precise beam control to minimize interference and optimize channel occupancy, enabling efficient transmission of UpLink (UL) signals through specific Tx beams and power management to avoid collisions with other RATs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If omnidirectional LBT is used in unlicensed band, then channel access is simple and covers all directions, but interference with other RATs increases and transmission reliability deteriorates due to high path-loss above 52.6 GHz
Solution Approach 1:
The patent divides the omnidirectional channel access into multiple directional LBT operations, where the transmitter performs LBT separately in different spatial directions using beamforming. This segmentation allows the system to maintain simplicity in each directional check while improving overall reliability by identifying clear channels in specific directions, thus resolving the contradiction between operational simplicity and transmission reliability in high-frequency bands.
Solution Approach 2:
The patent introduces spatial dimensionality to the LBT process by transitioning from omnidirectional (360-degree) channel sensing to directional beam-based sensing. By adding the spatial angle dimension to channel access, the system can achieve more reliable signal transmission in high-frequency bands while maintaining operational feasibility through structured directional scanning procedures.
2Area of stationary object
If higher transmission power is used to overcome path-loss above 52.6 GHz, then signal coverage improves, but interference with other RATs increases and channel occupancy becomes more difficult
Solution Approach 1:
The patent applies local quality by concentrating transmission power into focused directional beams rather than omnidirectional radiation. Each beam targets a specific spatial region with optimized power levels, providing sufficient coverage in the intended direction while minimizing interference in other directions. This localized power distribution resolves the contradiction between achieving adequate signal coverage and reducing harmful interference to other radio access technologies.
Solution Approach 2:
The patent introduces directional beamforming as an intermediary mechanism between the transmitter and the channel. The beamforming process acts as a mediator that shapes and directs energy spatially, enabling the system to achieve extended coverage in specific directions without proportionally increasing interference in all directions. This intermediary approach allows coverage expansion while managing interference through spatial selectivity.
3Reliability
If directional LBT with multiple beams is implemented, then transmission reliability improves and interference is reduced, but device complexity and computational requirements increase
Solution Approach 1:
The patent implements periodic directional LBT operations where the transmitter systematically scans through different beam directions in a predetermined sequence. This periodic structure transforms the complex multi-beam LBT process into a manageable repeating cycle, where each period covers all necessary directional checks. The periodic approach maintains reliability through comprehensive directional coverage while reducing complexity by providing a structured, repeatable procedure that can be efficiently implemented and tracked.
Data Source
AI summary
The present disclosure discloses a method by a terminal transmits an uplink (UL) signal in a wireless communication system. In particular, the method comprises: determining an energy detection (ED) threshold value on the basis of maximum effective isotropic radiated power (EIRP) from among at least one of pieces of first EIRP for at least one first UL signal; acquiring channel occupancy on the basis of the ED threshold value; and, within the channel occupancy, (i) transmitting the at least one first UL signal on the basis of each of at least one of pieces of first EIRP for each of the at least one first UL signal, and (ii) transmitting a second UL signal on the basis of second EIRP, wherein the second EIRP is less than or equal to the maximum EIRP.