SSB Frequency Position Mapping for High-Frequency NR-U Search
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Solution Overview
Problem
In the high-frequency bandwidth range of NR-U, determining the position of synchronization rasters for SSBs is challenging due to varying channel bandwidths and subcarrier spacings, which complicates the search process for SSBs.
Innovation Solution
The method involves determining the frequency position of SSBs based on the position of a first synchronization raster in a target bandwidth, considering factors such as subcarrier spacing, target bandwidth size, reserved bandwidth at the boundary, and information about the first channel, particularly CORESET#0, to facilitate SSB detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple synchronization rasters are defined in NR-U system to support flexible channel bandwidths, then the adaptability to different bandwidth configurations is improved, but the device complexity for SSB searching increases
Solution Approach 1:
The patent applies local quality by defining different synchronization raster configurations for different frequency ranges. For frequency range 1 (FR1), multiple synchronization rasters are defined to support flexible bandwidths, while for frequency range 2 (FR2), a single synchronization raster is used. This localized differentiation resolves the contradiction by adapting the number of synchronization rasters to the specific requirements of each frequency range, maintaining adaptability where needed while reducing complexity where channel bandwidths are fixed.
2Device complexity
If a single synchronization raster position is reserved per channel bandwidth in NR-U, then the device complexity for SSB searching is reduced, but the ability to determine SSB positions in high-frequency bandwidth ranges becomes more difficult
Solution Approach 1:
The patent introduces an intermediary approach by using a single synchronization raster as a reference point in high-frequency bands, from which other SSB positions can be derived using predefined offset relationships. This intermediary synchronization raster simplifies the searching process while still enabling the determination of multiple SSB positions through mathematical relationships, thus resolving the contradiction between reduced complexity and maintained detectability.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a one-dimensional approach (searching multiple synchronization rasters in frequency domain) to a two-dimensional approach (using a single synchronization raster position combined with time-domain offsets and frequency-domain offsets). This dimensional change allows the system to maintain SSB position determination capability while reducing the number of synchronization rasters that need to be searched.
3Area of stationary object
If synchronization rasters are spaced at 20 MHz intervals in high-frequency bands, then the coverage range is expanded, but the precision in determining specific SSB frequency positions is reduced
Solution Approach 1:
The patent applies segmentation by dividing the SSB position determination into multiple components: a coarse 20 MHz spaced synchronization raster for coverage, plus finer granularity offsets (frequency offsets and time offsets) for precise positioning. This segmentation allows the system to achieve both wide coverage through the spaced rasters and high precision through the offset mechanisms, resolving the contradiction between coverage range and positioning precision.
Data Source
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AI summary
Implementations of the present disclosure provide a method and device for determining a frequency position of a synchronization signal and physical broadcast channel (PBCH) block (SSB). The method includes the following. A position of a first synchronization raster in a target bandwidth is determined, where the first synchronization raster is used for determining a frequency position of an SSB in the target bandwidth, and the position of the first synchronization raster in the target bandwidth is associated with one or more of following information: a subcarrier spacing of the SSB, a size of the target bandwidth, a size of a reserved bandwidth at a boundary of the target bandwidth, and information of a first channel in the target bandwidth, where a frequency range of the first channel does not overlap with the SSB. The frequency position of the SSB is determined according to the position of the first synchronization raster in the target bandwidth. With implementations of the disclosure, in the high-frequency bandwidth range of NR-U, the frequency position of the SSB can be determined according to the position of the first synchronization raster in the target bandwidth, so as to search for the SSB.