SSB Transmission Indication for Unlicensed Channel Timing Uncertainty
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Solution Overview
Problem
In unlicensed frequency band communications systems, the uncertainty in channel availability due to contention-based access leads to missed transmission opportunities, causing issues with signal reception and network-side configurations like PDCCH monitoring and radio environment measurement.
Innovation Solution
An SSB transmission indication method that includes sending and receiving SSB transmission indication information to indicate candidate time positions, using bitmaps and quasi co-location indexes to manage SSB transmission, enabling effective rate matching, RO mapping, PDCCH monitoring, and PUCCH repetition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clear channel assessment (CCA) or extended clear channel assessment (eCCA) is performed before transmission on unlicensed frequency band, then channel availability is ensured, but transmission timing uncertainty increases causing missed SSB transmission opportunities
Solution Approach 1:
The network device pre-configures multiple candidate time positions for SSB transmission before actual transmission. The terminal device is provided with indication information about these candidate positions in advance, allowing both devices to prepare for potential transmission opportunities without waiting for channel assessment results
Solution Approach 2:
The system dynamically selects which candidate time position to use for SSB transmission based on channel assessment results. The network device can flexibly choose from multiple pre-configured positions depending on when the channel becomes available, adapting to the uncertain timing conditions of unlicensed band access
2Productivity
If SSB is transmitted at unknown time positions due to channel availability uncertainty, then transmission probability is maintained, but signal reception reliability deteriorates
Solution Approach 1:
The terminal device receives indication information from the network device that provides feedback about which candidate time position was actually selected for SSB transmission. This feedback mechanism allows the terminal to accurately determine when to expect the SSB signal, maintaining reception reliability even though the actual transmission time is not predetermined
Solution Approach 2:
Multiple candidate time positions are pre-configured for SSB transmission. The terminal device is provided with indication information about these candidate positions in advance, allowing both devices to prepare for potential transmission opportunities without waiting for channel assessment results
Data Source
AI summary
An SSB transmission indication method and apparatus, a terminal, a device, and a medium. The method is applied to a terminal, and the method includes: receiving SSB transmission indication information, where the SSB transmission indication information is used to indicate a candidate time position of an SSB.