Sidelink Cyclic Prefix Extension to Prevent Channel Preemption
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Solution Overview
Problem
In sidelink communication based on license-free spectrum, after listen-before-talk (LBT) succeeds, there is a time period before the slot boundary where another device can preempt the channel, preventing the terminal device from initiating sidelink communication.
Innovation Solution
Implementing a first cyclic prefix extension (CPE) before communication using a sidelink resource, with the length of the CPE indicated by a first length, either transmitted by the terminal device or network device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sidelink communication starts from slot boundary only, then communication structure is simple and standardized, but channel can be preempted by other devices between LBT success and slot boundary
Solution Approach 1:
The patent applies preliminary action by transmitting the cyclic prefix extension signal before the scheduled slot boundary to preemptively secure the channel. This preliminary transmission fills the time gap between LBT success and the slot boundary, preventing other devices from accessing the channel during this interval and ensuring reliable sidelink communication initiation.
Solution Approach 2:
The patent applies preliminary anti-action by using the cyclic prefix extension signal to counteract the potential channel preemption by other devices. This extension signal acts as a protective measure in advance, occupying the channel resources before the actual sidelink communication begins, thereby preventing harmful interference from other communications.
2Reliability
If cyclic prefix extension is transmitted before slot boundary, then channel preemption is prevented, but transmission structure becomes more complex
Solution Approach 1:
The patent applies universality by making the cyclic prefix extension signal serve multiple functions: it extends the cyclic prefix for signal processing purposes and simultaneously acts as a channel reservation mechanism to prevent preemption. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in system complexity while achieving reliable communication initiation.
Data Source
AI summary
The present application provides a communication method, a terminal device, and a network device. The communication method includes: before performing communication by means of a first sidelink resource, a terminal device sends a first cyclic prefix extension (CPE), where the length of the first CPE is a first length. The first length may be determined based on first information indicated by a network device.