Unlicensed-Band Sidelink Resource Pool Selection Using LBT
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Solution Overview
Problem
Existing wireless communication systems face challenges in performing sidelink communication in unlicensed bands due to issues like high pathloss, phase-noise, and frequency offset, particularly in high carrier frequencies, and there is a need for efficient resource pool configuration and selection methods to support applications such as eMBB, mMTC, uMTC, and URLLC.
Innovation Solution
A method for sidelink communication in unlicensed bands involving user equipment (UE) that receives resource pool configuration information, performs listen before talk (LBT) operations, and selects sidelink resources based on LBT results, LBT counter, and channel busy ratio (CBR) to ensure efficient transmission opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sidelink communication is performed in unlicensed bands at high carrier frequencies, then communication coverage and capacity are improved, but pathloss, phase-noise, and frequency offset increase
Solution Approach 1:
The patent performs LBT (Listen Before Talk) operations before sidelink transmission to detect channel availability and assess channel conditions. This preliminary action allows the system to identify suitable transmission opportunities in unlicensed bands, selecting resource pools when channel conditions are favorable, thereby improving communication reliability while maintaining high carrier frequency benefits
Solution Approach 2:
The patent dynamically selects sidelink resource pools based on LBT results, LBT counters, and channel busy ratios. By changing operational parameters (resource pool selection) according to real-time channel conditions detected through LBT, the system adapts to varying pathloss and frequency offset conditions, maintaining reliable communication while utilizing high carrier frequencies for improved capacity
2Ease of operation
If resource pool selection is performed without considering LBT results, then resource allocation simplicity is maintained, but transmission reliability in unlicensed bands deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where LBT results, LBT counter values, and channel busy ratio measurements are fed back into the resource pool selection process. This feedback loop enables the system to automatically adjust resource pool selection based on channel conditions, improving transmission reliability while maintaining relatively simple resource allocation procedures through standardized feedback processing
Solution Approach 2:
The system performs self-service by autonomously selecting appropriate sidelink resource pools based on its own LBT measurements and channel assessments. Each UE independently evaluates channel conditions through LBT operations and selects resource pools accordingly, eliminating the need for complex centralized resource allocation while ensuring transmission reliability through condition-based selection
3Adaptability or versatility
If multiple sidelink resource pools are configured for different LBT bandwidths, then resource allocation flexibility is improved, but device complexity and selection difficulty increase
Solution Approach 1:
The patent segments the unlicensed band into multiple LBT bandwidths, each with its own sidelink resource pool configuration. This segmentation allows independent optimization of each bandwidth segment based on channel conditions, providing flexibility in resource allocation while simplifying selection through clear segmentation boundaries and dedicated resource pools for each LBT bandwidth
Solution Approach 2:
The system performs preliminary LBT operations across different LBT bandwidths to assess channel availability before transmission. By pre-evaluating channel conditions in each segmented bandwidth and identifying suitable resource pools in advance, the system reduces real-time selection complexity while maintaining flexibility to allocate resources across multiple bandwidth segments based on assessed conditions
Data Source
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AI summary
A method of performing, by a user equipment (UE), sidelink communication based on an unlicensed band in a wireless communication system may include receiving, by the UE, sidelink resource pool configuration information from a base station based on higher layer signaling, generating a sidelink (SL) grant if data is generated in a logical channel (LCH) based on the sidelink resource pool configuration information, selecting a sidelink resource pool depending on whether hybrid automatic repeat and request (HARQ) feedback is configured to the data that is generated in the LCH based on the sidelink resource pool configuration information, and selecting a sidelink resource from the selected sidelink resource pool, and performing sidelink transmission.