Directional LBT Sensing Beam Configuration for 5G NR Channel Access
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Solution Overview
Problem
Current wireless communication systems, particularly in the context of 5G NR, face challenges in efficiently managing channel access procedures in unlicensed bands, especially in high-frequency bands like 60 GHz, where path loss is significant, and there is a need for directional beamforming to overcome coverage limitations and ensure coexistence with other wireless technologies.
Innovation Solution
The proposed method involves configuring and indicating sensing beams for directional listen-before-talk (LBT) procedures, allowing for directional transmission in specific beam directions, and sharing channel occupancy times (COT) with cyclic prefix extension, enabling efficient channel access and transmission in unlicensed bands by determining appropriate sensing and transmission beams based on received information from the base station or through internal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If directional beamforming is used in high-frequency bands, then coverage and signal strength are improved, but channel access complexity and interference management difficulty increase
Solution Approach 1:
The patent segments the channel access procedure into distinct phases: first performing LBT in a first beam direction to acquire initial channel occupancy time, then performing additional LBT in a second beam direction before final transmission. This segmentation allows the system to manage directional beamforming complexity by breaking down the channel access process into manageable steps, each targeting specific spatial directions.
2Reliability
If LBT is performed in multiple beam directions, then channel access reliability is improved, but time consumption increases
Solution Approach 1:
The patent applies preliminary action by performing LBT in the first beam direction before the second beam direction. The channel occupancy time acquired from the first LBT procedure is used as a basis for the second LBT, allowing the system to build upon previous findings rather than starting fresh. This preliminary action reduces redundant sensing and accelerates the overall channel access process while maintaining reliability through multi-directional verification.
3Device complexity
If beam correspondence is assumed between DL and UL, then device complexity is reduced, but accuracy of beam selection deteriorates
Solution Approach 1:
The patent addresses parameter changes by explicitly determining whether beam correspondence holds between downlink and uplink directions. When beam correspondence does not hold, the system adjusts the spatial relation parameters by selecting different reference signals for uplink beam determination compared to downlink operations. This allows the system to adapt to varying propagation conditions and maintain beam selection accuracy without forcing incorrect beam correspondence assumptions.
Data Source
AI summary
The present disclosure discloses a method for a terminal transmitting an uplink signal in a wireless communication system. Particularly, the method comprises: receiving information related to a downlink reference signal associated with an uplink signal; on the basis of the information, determining a sensing beam and a transmission beam for the uplink signal; carrying out sensing for the sensing beam; and, on the basis that a channel corresponding to the sensing beam is IDLE, transmitting the uplink signal through the transmission beam.