PBCH On-Off Indication for SSB Position Search
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Solution Overview
Problem
In 5G wireless communication, user equipment (UE) faces inefficiencies in initial access due to wasting time searching for cell-defining synchronization signal blocks (SSBs), especially when frequency bands of different operators are separated, leading to poor performance in SSB searching.
Innovation Solution
The method involves acquiring on-off indication information from non-cell-defining SSBs to set SSB position indication information or gap indication information in the PBCH, allowing UE to skip certain frequency bands to efficiently search for cell-defining SSBs by indicating their positions or ranges to reduce searching time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If UE searches for cell-defining SSB by decoding every SSB in frequency bands, then it can find the correct SSB, but it wastes time especially when non-cell-defining SSBs are encountered first
Solution Approach 1:
The base station performs preliminary action by setting the RMSI presence flag in the PBCH payload of non-cell-defining SSBs before transmission. This flag indicates whether RMSI is present or absent, allowing UE to quickly determine if an SSB is cell-defining without full decoding, thus reducing searching time while maintaining reliable access.
Solution Approach 2:
The RMSI presence flag acts as an intermediary indicator between the base station and UE. Instead of requiring UE to decode entire SSBs to determine if they are cell-defining, the flag provides intermediate information that guides UE's search process, reducing time loss while ensuring correct SSB identification.
2Loss of time
If position of cell-defining SSB is indicated in non-cell-defining SSB, then searching time is reduced, but it doesn't work when frequency bands of different operators are separated
Solution Approach 1:
The invention changes the parameter being indicated from absolute frequency position to relative gap information. Instead of indicating the exact position of cell-defining SSB which fails in separated frequency band scenarios, the patent indicates a gap value that tells UE how many SSB positions to skip, making the solution adaptable to different frequency band configurations including separated bands.
Solution Approach 2:
The frequency band search space is segmented into multiple positions based on the gap indication. Instead of treating the frequency band as a continuous search space, the patent divides it into discrete positions separated by gaps, allowing UE to efficiently skip non-cell-defining SSB positions and focus on potential cell-defining SSB locations regardless of frequency band separation.
Data Source
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AI summary
This disclosure relates to a method and an apparatus for indicating a position of a cell-defining synchronization signal block (SSB) and searching for the same, a base station, user equipment and a computer-readable storage medium. A method of indicating a position of a cell-defining SSB includes: acquiring on-off indication information set in a physical broadcast channel (PBCH) of a non-cell-defining SSB, where the on-off indication information is a first value or a second value; setting, in response to that the on-off indication information is the first value, SSB position indication information in the PBCH to indicate a position of a raster or a raster group in which a cell-defining SSB is located; setting, in response to that the on-off indication information is the second value, gap indication information in the PBCH to indicate that there is no cell-defining SSB within a range of a current frequency band, wherein the range has a length of a gap value and is centered at a position of the current SSB; and sending the SSB to user equipment (UE). The examples of the present disclosure enable the UE to reduce the searching time.