Sidelink LBT Bandwidth Coordination for Wider Unlicensed Transmission
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Solution Overview
Problem
Existing SL-U communication technologies fail to provide adequate solutions for wideband or bandwidth-enhanced SL transmissions that span multiple LBT bandwidths, particularly in the unlicensed spectrum, and do not address SL transmissions in intra-frequency guard bands of LBT bandwidths.
Innovation Solution
The UE performs LBT procedures across multiple LBT bandwidths to enable SL-U transmissions, adapts the SL BWP based on CCA procedures, and configures guard bands for wideband SL-U communications, allowing for enhanced bandwidth utilization in the unlicensed band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SL transmissions are performed in the unlicensed spectrum using traditional single LBT bandwidth methods, then the communication can operate with simple LBT procedures, but the throughput and bandwidth utilization are limited
Solution Approach 1:
The patent divides the unlicensed spectrum into multiple LBT bandwidths (first LBT bandwidth and second LBT bandwidth) that can be independently accessed. The UE performs separate LBT procedures for each LBT bandwidth and can transmit SL messages in multiple bandwidths simultaneously, thereby increasing overall throughput while maintaining manageable complexity through modular LBT execution.
Solution Approach 2:
The patent introduces a frequency dimension by enabling SL transmissions across multiple LBT bandwidths simultaneously. Instead of using a single bandwidth, the system exploits the frequency domain by configuring multiple BWPs (bandwidth parts) that overlap with different LBT bandwidths, allowing parallel transmissions and achieving bandwidth enhancement.
2Area of stationary object
If SL BWP is configured to span multiple LBT bandwidths, then bandwidth utilization is enhanced, but the LBT procedures and channel access become more complex
Solution Approach 1:
The SL BWP is segmented into multiple portions that can be mapped to different LBT bandwidths. Each portion can be independently accessed through separate LBT procedures. The UE configures multiple BWPs within the SL BWP, where each BWP corresponds to a specific LBT bandwidth, allowing independent channel access and reducing the complexity of managing the entire bandwidth as a single unit.
Solution Approach 2:
The patent introduces dynamic BWP configuration where the network can activate or deactivate specific BWPs based on channel conditions and traffic requirements. The UE can dynamically switch between different BWPs and adjust which LBT bandwidths are used for transmission, providing flexibility to adapt to changing conditions while maintaining optimized bandwidth utilization.
3Productivity
If independent LBT procedures are performed for each LBT bandwidth, then the SL message can be transmitted in multiple bandwidths simultaneously for higher throughput, but the time required for channel access increases
Solution Approach 1:
The patent implements preliminary LBT procedures where the UE performs channel sensing and access attempts in advance for multiple LBT bandwidths. The network configures multiple BWPs and provides advance indication of which BWPs are activated. This allows the UE to prepare transmission resources and complete LBT procedures beforehand, reducing the actual channel access time when transmission is needed.
Solution Approach 2:
The patent merges multiple LBT procedures by allowing the UE to perform channel access across multiple LBT bandwidths in a coordinated manner. Instead of sequentially accessing each bandwidth, the system combines the LBT processes and enables simultaneous transmission in multiple bandwidths once channel access is granted, thereby reducing total access time while maintaining high throughput.
Data Source
AI summary
Techniques discussed herein can facilitate sidelink (SL) transmissions in the unlicensed spectrum. One example aspect is a baseband processor of a user equipment (UE) including one or more processors configured to perform a first listen before talk (LBT) procedure and a second LBT procedure, where the first LBT procedure is performed according to a first LBT bandwidth (BW) (LBT BW1), and the second LBT procedure is performed according to a second LBT bandwidth (LBT BW2). The one or more processors are further configured to transmit a SL message, in an unlicensed spectrum, after completing the first LBT procedure and the second LBT procedure, where the SL message is transmitted in a SL BWP that overlaps with the LBT BW1 and the LBT BW2.