Distributed-RU Pilot Tone Layout for 6 GHz Interference Avoidance
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Solution Overview
Problem
Current pilot tone designs for distributed-tone resource units (dRUs) in 6 GHz low-power indoor (LPI) systems result in clustered pilot tones, leading to narrowband interference issues due to stringent Federal Communications Commission (FCC) regulations and inefficient distribution of pilot tones.
Innovation Solution
A hierarchical structure-based pilot tone design is proposed, distributing pilot tones over an entire bandwidth with no adjacent tones, maintaining regular RU pilot tone hierarchies, and ensuring even or near-even distribution across dRUs, using subcarrier distribution and reuse of regular RU pilot tone values and mappings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pilot tones are assigned in dRUs using conventional methods, then the hierarchical structure for regular RU pilot tones is maintained, but pilot tones become clustered and cause narrowband interference
Solution Approach 1:
The patent segments the dRU bandwidth into multiple subblocks and assigns pilot tones to specific subblocks based on RU index and size. This segmentation prevents pilot tone clustering by ensuring pilots are distributed across different frequency subblocks rather than concentrated in one location, thereby avoiding narrowband interference while maintaining manageable complexity through systematic assignment rules.
Solution Approach 2:
The patent applies local quality by making pilot tone assignment location-dependent on the specific dRU configuration (RU index, RU size, and subblock structure). Each dRU receives pilot tones tailored to its specific frequency location and size, optimizing interference avoidance for each local context while maintaining overall system coherence through the hierarchical structure.
2Reliability
If pilot tones are distributed over entire bandwidth with no adjacent tones, then narrowband interference is avoided, but the distribution complexity increases
Solution Approach 1:
The bandwidth is divided into multiple subblocks, and pilot tones are assigned to specific subblocks based on deterministic rules involving RU index and size. This segmentation approach ensures non-adjacent pilot tone distribution across the bandwidth while avoiding the need for complex optimization algorithms, as the subblock-based assignment naturally spaces out pilot tones.
Solution Approach 2:
The patent performs preliminary action by pre-defining the subblock structure and pilot tone assignment rules before actual pilot tone generation. The subblocks are predetermined, and the assignment methodology is established in advance based on RU characteristics, simplifying the actual pilot tone distribution process while ensuring adequate separation.
3Power
If distributed-tone RUs are used to spread subcarriers over wider bandwidth, then transmit power is boosted and coverage range is extended, but pilot tones from multiple dRUs are squeezed into clusters at the receiver
Solution Approach 1:
The patent segments the frequency bandwidth into multiple subblocks and assigns pilot tones from different dRUs to different subblocks based on their RU indices and sizes. This segmentation prevents the squeezing effect by ensuring that even though multiple dRUs transmit simultaneously, their pilot tones are distributed across the frequency spectrum rather than concentrated at the receiver, maintaining reliable pilot tone reception quality.
4Adaptability or versatility
If hierarchical structure for regular RU pilot tones is maintained for dRUs, then design consistency is achieved, but pilot tone clustering occurs
Solution Approach 1:
The patent maintains design consistency by preserving the hierarchical structure for determining the number of pilot tones based on dRU size (26-tone, 52-tone, 106-tone, 242-tone categories), while simultaneously applying segmentation by assigning these pilot tones to different frequency subblocks. This dual approach achieves both design consistency through hierarchical rules and interference avoidance through spatial distribution across subblocks.
Solution Approach 2:
The patent applies local quality by making the specific subblock assignment location-dependent on the dRU's frequency position and characteristics. While the hierarchical structure determines the number of pilot tones (maintaining consistency), the specific subblock locations are locally optimized based on RU index and frequency position, preventing clustering while preserving the hierarchical design framework.
Data Source
AI summary
Various schemes pertaining to pilot tone design for distributed-tone resource units (dRUs) in 6 GHz low-power indoor (LPI) systems are described. A communication entity generates a plurality of pilot tones of a dRU based on a hierarchical structure of pilot tones that is used for a regular RU (rRU). The communication entity then communicates with another communication entity using the dRU.