DM-RS Pattern Design for LTE-NR Coexistence
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Solution Overview
Problem
In wireless communication networks, especially in 5G networks, the coexistence of different radio access technologies like LTE and NR poses challenges in minimizing interference and efficiently using resources, particularly in the context of reference signaling.
Innovation Solution
The method involves transmitting demodulation reference signaling (DM-RS) with specific patterns in frequency domains, using a repeated flush arrangement of pattern elements separated by an interrupting pattern, allowing for efficient coexistence without interference, and enabling flexible allocation of data on resource elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LTE and NR systems operate in the same frequency range, then spectrum utilization is improved, but interference between the two systems increases
Solution Approach 1:
The patent segments the frequency spectrum into distinct resource blocks and assigns different reference signal patterns to different segments. LTE uses traditional CRS patterns while NR uses DM-RS patterns, allowing simultaneous operation in the same frequency range with minimized interference through frequency-domain segmentation and orthogonal resource allocation.
Solution Approach 2:
The patent introduces coordination mechanisms and signaling protocols as intermediaries between LTE and NR systems. These intermediaries enable the systems to negotiate and coordinate resource allocation, particularly for reference signals, allowing coexistence in overlapping frequency ranges while maintaining acceptable interference levels.
2Measurement precision
If reference signals are transmitted frequently for reliable demodulation, then demodulation accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent implements DM-RS patterns that transmit reference signals only at specific partial positions within resource blocks rather than uniformly across all subcarriers. This partial action approach maintains sufficient demodulation accuracy by placing reference signals at critical positions while reducing overall signaling overhead compared to full-coverage reference signal transmission.
Solution Approach 2:
The patent applies different reference signal patterns and densities to different local regions of the frequency spectrum based on local channel conditions and service requirements. DM-RS patterns with varying densities are applied locally to match the specific needs of different resource blocks, optimizing the balance between demodulation accuracy and overhead on a local rather than global basis.
Data Source
AI summary
There is disclosed a method of operating a network node (100) in a NR radio access network, the method comprising transmitting demodulation reference signaling, DM-RS, associated to downlink channel signaling, the DM-RS having a DM-RS pattern in frequency domain over a range of subcarriers including a reference subcarrier, wherein in a first frequency range below the reference subcarrier, the DM-RS pattern comprises a first sub-pattern represented by a repeated flush arrangement of a pattern element covering a number NP of subcarriers, and in a second frequency range above the reference subcarrier, the DM-RS pattern comprises a second sub-pattern represented by a repeated flush arrangement of the pattern element, wherein the first sub-pattern and the second sub-pattern are separated in frequency domain by an interrupting pattern having a number NI of subcarriers, wherein NI>0 and NI is different from NP. The disclosure also pertains to related methods and devices.