Multiplexing Reference Signals With Scalable Numerology
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently multiplexing reference signals across different numerologies, which affects the flexibility and scalability of 5G NR networks, particularly in supporting diverse service applications and maintaining orthogonality of subcarriers.
Innovation Solution
Implementing a scaled numerology family across resource elements, where the base subcarrier spacing is scaled by an integer while maintaining the same cyclic prefix overhead, allowing for efficient multiplexing of reference signals using orthogonal cover codes or discrete Fourier transform (DFT) across OFDM symbols with different numerologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reference signals are multiplexed across different numerologies using traditional methods, then resource utilization is improved, but orthogonality of subcarriers is compromised
Solution Approach 1:
The patent applies parameter changes by scaling the subcarrier spacing of reference signals to match the data numerology. Specifically, when data uses a scaled numerology (e.g., 60 kHz subcarrier spacing), the reference signals are also scaled to the same numerology rather than using the base numerology (e.g., 15 kHz). This parameter adjustment maintains orthogonality while enabling efficient multiplexing across different numerologies.
2Adaptability or versatility
If scalable numerology is implemented for diverse service applications, then flexibility and scalability are improved, but complexity of multiplexing reference signals increases
Solution Approach 1:
The patent implements universality by creating a scalable numerology framework where reference signals can adapt to any data numerology through systematic scaling. The same reference signal designs (DMRS, CRS, CSI-RS, SRS) can be used across different numerologies by applying the appropriate scale factor, eliminating the need for separate reference signal designs for each numerology and reducing overall system complexity.
3Adaptability or versatility
If base subcarrier spacing is scaled by integer factors, then support for diverse service applications is improved, but maintaining same cyclic prefix overhead becomes more difficult
Solution Approach 1:
The patent maintains cyclic prefix overhead consistency through parameter changes by scaling both the subcarrier spacing and the cyclic prefix length proportionally. When the subcarrier spacing is scaled by a factor K, the cyclic prefix length is also scaled by the same factor K, thereby maintaining the same cyclic prefix overhead ratio. This ensures that timing synchronization and orthogonality properties are preserved across different numerologies.
Data Source
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AI summary
Wireless communication devices are adapted to facilitate multiplexing of reference signals. According to one example, a wireless communication device can multiplex a first reference signal and a second reference signal utilizing code division multiplexing for transmission across a first resource element and a second resource element. The first resource element may utilize a first subcarrier in a first OFDM symbol employing a first numerology. The second resource element may utilize a second subcarrier in a second OFDM symbol employing a second numerology that is different from the first numerology, where the second subcarrier overlaps in frequency at least a portion of the first subcarrier. Code division multiplexing (or Orthogonal Cover Code) of Reference Signals (DMRS) over Resource Elements (RE) having different subcarrier spacings (also proportionally different symbol durations). Usual OCCs codes are proposed like the 3-DFT one for 3 REs case. Only subcarriers with aligned center frequency across the different numerologies are allocated for mapping the DMRS.