Dual Raster Grids for RIS-Aware Synchronization Signal Blocks
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently supporting initial access procedures for user equipment (UEs) that do support and do not support reconfigurable intelligent surfaces (RISs), particularly in obstructed paths, leading to difficulties in detecting synchronization signal blocks (SSBs).
Innovation Solution
Implementing two synchronization raster grids and two types of SSBs, one for UEs that support RISs and another for those that do not, allowing UEs to identify and receive SSBs based on their capabilities and the presence of RISs, with distinct primary synchronization signals, mapping orders, and demodulation reference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single synchronization raster grid is used for all UEs, then device complexity is reduced, but reliability of initial access deteriorates in obstructed environments for RIS-capable UEs
Solution Approach 1:
The patent divides the synchronization raster grid into two separate grids: a first synchronization raster grid for legacy UEs and a second synchronization raster grid for RIS-capable UEs. This segmentation allows each grid to be optimized for its specific UE type, improving initial access reliability for RIS-capable UEs in obstructed environments without compromising legacy UE compatibility.
2Reliability
If separate synchronization raster grids are implemented for RIS-capable and legacy UEs, then initial access reliability improves, but device complexity increases
Solution Approach 1:
The patent designs the dual synchronization raster grid system to be universally compatible with both legacy UEs and RIS-capable UEs. The base station can transmit SSBs on both grids, and each UE type can independently identify and use its designated grid, allowing the system to serve multiple UE capabilities without requiring separate independent systems.
3Difficulty of detecting and measuring
If UEs monitor both synchronization raster grids, then detection capability improves, but loss of time increases due to extended search space
Solution Approach 1:
The patent enables UEs to identify their capability status (RIS-capable or legacy) and selectively monitor only the appropriate synchronization raster grid. RIS-capable UEs monitor the second synchronization raster grid optimized for their capabilities, while legacy UEs monitor the first grid, eliminating unnecessary monitoring and reducing initial access time.
4Adaptability or versatility
If different types of SSBs are transmitted for RIS-capable and legacy UEs, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent transmits different types of SSBs with distinct parameters including different primary synchronization signals, mapping orders, and demodulation reference signals for RIS-capable versus legacy UEs. These parameter changes enable the system to adapt to different UE capabilities while maintaining a unified transmission framework from the base station.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. Generally, the described techniques provide for performing initial access procedures including transmitting or receiving synchronization signal blocks (SSBs) based on a capability of a user equipment (UE) to use reconfigurable intelligent surfaces (RISs). In some examples, a base station may transmit SSBs using two synchronization raster grids. For example, the base station may transmit SSBs on a first synchronization raster grid for UEs that do not support RISs and on a second synchronization raster grid for UEs that support RISs. In some examples, a base station may transmit different types of SSBs. For example, a base station may transmit a first type of SSB for UEs that do not support RISs and a second type of SSB for UEs that support RISs. A UE may search for and receive SSBs according to a capability of the UE.