D2D Indication Signal Transmission in Unlicensed Bands
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Solution Overview
Problem
Existing D2D transmission resource configuration modes are not well suited for unlicensed frequency bands due to uncertainty in accessing channels.
Innovation Solution
The method involves a first terminal device sending indication information to a second terminal device for signal transmission resources, performing listen before talk (LBT) before transmission, and using this information to accurately transmit at configured resource locations, supporting flexible frame structures in unlicensed frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resource pool-based resource configuration mode is used for D2D communication, then resource allocation is simplified and ease of operation is improved, but adaptability to unlicensed frequency bands deteriorates due to channel access uncertainty
Solution Approach 1:
The patent introduces dynamic resource allocation mechanisms that adapt to channel conditions in unlicensed bands. The system dynamically adjusts resource pool configurations and transmission parameters based on LBT outcomes and channel occupancy status, transforming the static resource pool approach into a dynamic system that can respond to changing channel availability.
Solution Approach 2:
The patent modifies key parameters including channel occupancy time (COT), resource pool timing configurations, and transmission power levels to accommodate unlicensed band requirements. These parameter changes enable the system to adapt the resource pool-based allocation to the uncertain channel access environment of unlicensed frequencies.
2Reliability
If LBT is performed before transmission in unlicensed bands, then channel access compliance is improved, but transmission timing accuracy deteriorates due to uncertainty in channel access
Solution Approach 1:
The patent performs LBT operations in advance of scheduled transmissions and pre-configures resource pools with timing offsets that account for potential LBT delays. By performing channel access checks beforehand and preparing transmission resources in advance, the system mitigates the impact of LBT-induced timing uncertainties.
Solution Approach 2:
The system implements feedback mechanisms where transmission timing is adjusted based on actual LBT outcomes and channel occupancy feedback. The base station receives timing feedback from terminal devices and adjusts subsequent resource allocations to compensate for timing variations introduced by LBT procedures.
3Ease of operation
If fixed feedback channel resources are allocated in NR-V2X, then resource allocation is simplified, but resource wastage increases due to inability to adapt to channel occupancy variations
Solution Approach 1:
The patent introduces dynamic feedback channel resource allocation where the timing and resources for feedback channels are adjusted based on actual channel occupancy duration and LBT outcomes. This dynamic approach allows the system to allocate feedback resources more efficiently, reducing waste while maintaining ease of operation through automated adjustments.
4Reliability
If channel occupancy duration is extended to protect transmissions, then transmission reliability is improved, but spectral efficiency deteriorates due to reduced channel availability for other users
Solution Approach 1:
The patent dynamically adjusts channel occupancy time (COT) parameters based on traffic conditions, channel availability, and priority levels. Instead of using fixed extended COT, the system optimizes COT duration to provide adequate transmission protection while minimizing impact on spectral efficiency through adaptive parameter adjustment.
Data Source
AI summary
This application provides example signal transmission method and apparatus. One example method includes sending, by a first terminal device to a second terminal device, indication information indicating a signal transmission resource. Listen before talk (LBT) is performed by the first terminal device before transmission with the second terminal device is performed. Transmission with the second terminal device is performed by the first terminal device according to the indication information.