SSB Transmission in Unlicensed Bands via Channel Detection
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Solution Overview
Problem
In NR communication systems, transmitting SSBs in the unlicensed band is challenging due to the uncertainty of the channel, which affects RRM measurement and initial access.
Innovation Solution
A signal transmitting method that performs channel detection on a time domain transmission unit in the unlicensed band and transmits SSBs accordingly, ensuring that SSBs are sent in idle channels, thereby improving transmission reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel detection is performed before SSB transmission in unlicensed band, then transmission reliability is improved, but transmission time is increased
Solution Approach 1:
The base station performs channel detection before SSB transmission to ensure the channel is idle, which is a preliminary action that prevents transmission failures. This LBT mechanism is mandatory in unlicensed bands to ensure fair sharing and avoid interference with other systems like WiFi and radar.
Solution Approach 2:
SSBs are transmitted periodically in bursts within 5ms time windows according to configured periods ({5,10,20,40,80,160}ms). The channel detection is performed periodically before each transmission opportunity, balancing reliability requirements with time efficiency through structured periodic operations.
2Area of stationary object
If SSBs are transmitted in different spatial directions, then coverage is improved, but channel detection complexity is increased
Solution Approach 1:
The transmission system is segmented into multiple spatial directions (beams), with each direction having its own channel detection and transmission opportunity. This allows the base station to transmit SSBs in different spatial directions for broader coverage while managing complexity through structured segmentation of the transmission process.
Solution Approach 2:
The system adds a spatial dimension to channel detection by detecting channels in different transmission directions simultaneously or sequentially. This dimensional expansion enables the base station to identify idle channels across multiple spatial sectors, improving coverage without proportionally increasing detection complexity.
3Reliability
If LBT is performed for each SSB transmission, then channel access reliability is improved, but transmission efficiency is reduced
Solution Approach 1:
Multiple channel detection operations are merged into a single LBT procedure when transmitting SSBs in the same time window and spatial direction. This combining approach reduces the total number of detection operations while maintaining reliable channel access, thereby improving transmission efficiency without sacrificing reliability.
Solution Approach 2:
Once the channel is detected as idle through LBT, the base station can continuously transmit SSBs in the same spatial direction without repeated detection, maintaining useful transmission action. This continuous transmission capability improves efficiency while the initial detection ensures reliability.
Data Source
AI summary
The present disclosure provides a signal transmitting method and a network equipment. The signal transmitting method includes: performing channel detection on a time domain transmission unit on an unlicensed band; transmitting a synchronization signal block (SSB) according to a detection result of the channel detection, wherein the time domain transmission unit comprises at least one SSB.