NCD-SSB Symbol Marking for RedCap UE Synchronization
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Solution Overview
Problem
In 5G NR wireless communication systems, reduced capability (RedCap) user equipment (UE) devices face challenges in using cell-defining synchronization signal blocks (CD-SSBs) for beam mobility and random access channel (RACH) operations due to limited bandwidth, as CD-SSBs may fall outside their allocated frequency window, necessitating alternative methods for synchronization and access.
Innovation Solution
The implementation of non-cell-defining synchronization signal blocks (NCD-SSBs) within RedCap-specific bandwidth parts (BWPs), which allows RedCap UEs to use NCD-SSBs for marking symbols and validating RACH occasions, enabling beam mobility and timing operations by configuring the frequency and time offset of NCD-SSB transmissions relative to CD-SSB transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If RedCap UEs use CD-SSBs for synchronization and random access, then beam mobility and RACH operations can be performed, but CD-SSBs may fall outside the allocated RedCap-specific BWP frequency window making them inaccessible
Solution Approach 1:
The patent divides the synchronization signal functionality into two types: CD-SSBs for cell-level synchronization and NCD-SSBs for UE-specific synchronization within the RedCap BWP. This segmentation allows RedCap UEs to use NCD-SSBs that are frequency-aligned with their allocated bandwidth, solving the accessibility problem while maintaining cell-level synchronization capabilities.
Solution Approach 2:
NCD-SSBs act as an intermediary between the cell-level CD-SSBs and the RedCap UE operations. The NCD-SSBs are transmitted within the RedCap-specific BWP frequency window and provide the necessary synchronization and random access functionality for RedCap UEs, bridging the gap between cell-level signals and UE-specific bandwidth constraints.
2Adaptability or versatility
If NCD-SSBs are configured for RedCap-specific BWP, then synchronization and access capabilities are improved within allocated bandwidth, but additional configuration complexity and validation requirements are introduced
Solution Approach 1:
The network configures NCD-SSB parameters including frequency offsets and time offsets in advance through RRC signaling. This preliminary configuration allows RedCap UEs to know exactly where to find NCD-SSBs within their allocated BWP before actual operation, reducing runtime complexity and enabling efficient synchronization and random access procedures.
Solution Approach 2:
The patent implements validation mechanisms where the network monitors and validates NCD-SSB configurations to ensure they fall within the RedCap-specific BWP frequency window. This feedback loop ensures configuration correctness and prevents operational errors, managing the complexity through systematic validation rather than ad-hoc checks.
Data Source
AI summary
This disclosure provides systems, methods, and devices for wireless communication that support marking symbols and validation of non-cell-defining-synchronization signal block (NCD-SSB) and random access channel (RACH) occasions within 5G new radio (NR) networks. In a first aspect, a method of wireless communication includes the UE obtaining an uplink-downlink configuration for one or more slots, an NCD-SSB configuration identifying NCD-SSB transmissions, and a bandwidth configuration identifying a bandwidth part (BWP) allocated to the UE and a configuration for cell-defining-synchronization signal block (CD-SSB) transmissions. The UE can mark a configured flexible symbol as a downlink symbol in response to either an NCD-SSB symbol or a CD-SSB symbol overlapping with the flexible symbol. Other aspects and features are also claimed and described.