Directional Clear Channel Assessment for 5G Unlicensed Spectrum
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Solution Overview
Problem
Current 5G communication systems face challenges in efficiently managing channel access in multi-beam operation scenarios, particularly on unlicensed spectra, due to false alarms from omni-directional clear channel assessment (CCA) methods, which can lead to reduced channel access opportunities and interference issues.
Innovation Solution
The implementation of a directional clear channel assessment (CCA) scheme, where antennas are configured to sense energy along preconfigured directions and angles, allowing for more precise channel sensing and reducing false alarms by using directional energy detection thresholds, enabling directional listen-before-talk (LBT) procedures for both downlink and uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If omni-directional clear channel assessment (CCA) is used, then channel sensing coverage is maximized, but false alarm rate increases leading to reduced channel access opportunities
Solution Approach 1:
The patent segments the omnidirectional channel sensing into multiple directional sensing operations. Instead of performing a single omnidirectional CCA that senses all directions simultaneously, the system divides the sensing into multiple directional CCAs, each targeting a specific beam direction. This segmentation allows the system to identify which specific directions have actual transmissions versus false alarms, thereby reducing the overall false alarm rate while maintaining comprehensive coverage.
Solution Approach 2:
The patent applies local quality by making the channel sensing特性 direction-specific. Each directional CCA uses tailored sensing parameters and thresholds appropriate for its specific direction, rather than applying a uniform omnidirectional threshold. This allows the system to adapt to local channel conditions in each direction, improving measurement precision and reducing false alarms caused by transmissions from irrelevant directions.
2Measurement precision
If directional clear channel assessment is implemented, then false alarm rate is reduced, but device complexity increases due to multiple sensing directions
Solution Approach 1:
The patent merges multiple directional CCA operations into a unified directional LBT framework. Instead of treating each directional sensing as an independent complex operation, the system combines them under a single coordinated process that shares sensing resources, timing structures, and decision-making logic. This merging reduces overall device complexity while maintaining the false alarm reduction benefits of directional sensing.
Solution Approach 2:
The patent creates a universal directional LBT framework that can handle multiple sensing directions using a common set of procedures and parameters. The directional CCA mechanism is designed to be multi-functional, capable of adapting to different beam configurations and directions without requiring separate dedicated systems for each direction. This universality reduces device complexity by eliminating redundant functionality.
3Productivity
If multiple directional sensing operations are performed, then channel access efficiency is improved, but time consumption for channel assessment increases
Solution Approach 1:
The patent performs preliminary directional sensing operations before final channel access decisions. By conducting directional CCAs in advance and identifying clear directions beforehand, the system prepares the channel access strategy in advance, reducing the time needed for final access decisions. This preliminary action allows the system to skip unnecessary sensing steps and directly access identified clear channels, improving overall efficiency while managing time consumption.
Solution Approach 2:
The patent maintains continuous channel sensing across multiple directions simultaneously or in rapid succession, rather than performing discrete sequential assessments. The directional LBT framework enables continuous monitoring of multiple beams, allowing the system to maintain channel knowledge across directions without interrupting useful transmission actions. This continuity improves channel access efficiency by eliminating gaps in sensing while managing overall assessment time.
Data Source
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AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-Generation (4G) communication system such as long term evolution (LTE). An apparatus for a directional listen-before-talk (LBT) operation in a wireless communication system, the apparatus comprising at least one processor configured to perform sensing of a channel based on a direction and a configurable directional energy threshold during an interval comprising at least one clear channel assessment (CCA) slot and a transceiver configured to transmit/receive at least one of discovery signal or data signal based on the sensing of the channel to/from another apparatus.