PBCH-DMRS Resource Mapping in NR SS Blocks
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Solution Overview
Problem
In New Radio (NR) systems, the lack of a full-bandwidth cell-specific reference signal (CRS) prevents pilot demodulation for the Physical Broadcast Channel (PBCH), necessitating a new resource mapping method for Demodulation Reference Signals (DMRS) to facilitate channel estimation.
Innovation Solution
A resource mapping method for DMRS that determines a target OFDM symbol within the NR SS block and maps the PBCH-DMRS in that symbol, utilizing unoccupied resources from the NR-PSS, NR-SSS, and NR-PBCH OFDM symbols, allowing for pilot demodulation and improved channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a full-bandwidth CRS is not introduced in NR SS block design, then the system complexity is reduced and new radio architecture is simplified, but pilot demodulation capability for PBCH is lost
Solution Approach 1:
The patent segments the reference signal functionality by introducing dedicated DMRS resources specifically for PBCH demodulation, rather than using a comprehensive full-bandwidth CRS. This segmentation allows the system to eliminate unnecessary CRS overhead while maintaining essential pilot demodulation capabilities through targeted DMRS placement in specific OFDM symbols and frequency resources.
Solution Approach 2:
The patent extracts the essential pilot demodulation function from the full-bandwidth CRS framework and implements it independently through DMRS. By taking out only the necessary reference signal functionality needed for PBCH demodulation and implementing it through a simplified DMRS structure, the system achieves reduced complexity while preserving the critical demodulation capability.
2Productivity
If DMRS resources are mapped in OFDM symbols occupied by NR-PSS, NR-SSS, or NR-PBCH, then resource utilization is improved, but signal interference and mapping complexity increase
Solution Approach 1:
The patent applies local quality by mapping DMRS resources to specific local positions within the OFDM symbol structure rather than uniformly across all resources. The DMRS is placed in unoccupied resource elements of specific OFDM symbols, creating localized reference signal regions that optimize resource utilization without requiring complex global mapping schemes.
Solution Approach 2:
The patent resolves mapping complexity by transitioning from a two-dimensional CRS mapping approach to a three-dimensional DMRS mapping approach that considers time (specific OFDM symbols), frequency (unoccupied resource elements), and code domain (different DMRS sequences). This dimensional expansion provides more flexibility in resource allocation and simplifies the mapping procedure.
Data Source
AI summary
A resource mapping method for a demodulation reference signal (DMRS) and a base station are provided. The method includes: determining a target orthogonal frequency division multiplexing (OFDM) symbol for mapping a physical broadcast channel (PBCH)-DMRS from OFDM symbols corresponding to a new radio (NR) synchronization signal block (SS block); and mapping the PBCH-DMRS in the target OFDM symbol.