ISAC Reference Signal Patterns for Delay-Doppler Sensing Range
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Solution Overview
Problem
Existing Reference Signal (RS) configurations in Integrated Sensing and Communication (ISAC) systems are inadequate for achieving high sensing resolution and flexibility, leading to ambiguity peaks in delay-Doppler estimation and excessive overhead, particularly in scenarios requiring coverage beyond 200 meters, such as UAV detection and remote object tracking.
Innovation Solution
Implementing a multi-level RS pattern set with symbol-based and slot-based configurations, allowing for scalable and flexible RS transmission, including parameters like RE spacing, staggering offsets, and burst configurations across time and frequency domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed time-frequency spacing RS configuration is used, then communication efficiency is maintained, but sensing resolution deteriorates and ambiguity peaks occur in delay-Doppler estimation
Solution Approach 1:
The patent segments the RS configuration into multiple hierarchical levels (L1, L2, L3) with different spacing parameters. L1 provides fine time-frequency spacing for high resolution, L2 provides coarser spacing for reduced overhead, and L3 provides even coarser spacing for coverage extension. This segmentation allows the system to achieve high sensing resolution through L1 while managing complexity through the hierarchical structure of L2 and L3.
Solution Approach 2:
The patent introduces a hierarchical dimension to the traditional flat RS configuration by organizing RS patterns into multiple levels (L1, L2, L3) with different spacing characteristics. This dimensional transformation allows simultaneous optimization of resolution (through L1 fine spacing) and overhead management (through L2/L3 coarser spacing patterns) in the time-frequency domain.
2Reliability
If standard CP length is used, then communication reliability is improved by eliminating ISI, but sensing range is limited to less than 200 meters
Solution Approach 1:
The patent implements dynamic CP extension where the CP length is adaptively increased for RS patterns targeting distant objects. The system determines extended CP lengths based on the desired sensing range, allowing the CP to dynamically adjust its duration to cover larger propagation delays while maintaining ISI elimination for both communication and extended-range sensing.
Solution Approach 2:
The patent changes the CP length parameter from a fixed standard value to an extended variable value. By introducing extended CP lengths that exceed the standard CP duration, the system extends the maximum detectable delay and thereby extends the sensing range beyond 200 meters while preserving the ISI elimination function through the extended guard period.
3Measurement precision
If high density RS patterns are deployed, then sensing resolution is improved, but overhead increases excessively
Solution Approach 1:
The patent segments the RS deployment density across different hierarchical levels. L1 patterns use fine spacing for high resolution but are deployed sparsely in the hierarchy. L2 and L3 patterns use coarser spacing and are deployed more densely in the hierarchical structure. This segmentation allows the system to achieve high effective resolution through L1 while limiting total overhead through the hierarchical organization of L2 and L3.
Solution Approach 2:
The patent resolves the overhead-resolution tradeoff by introducing a hierarchical dimension to RS deployment. Instead of uniformly increasing RS density across all patterns, the system uses hierarchical levels where only L1 patterns contribute maximally to resolution while L2 and L3 patterns provide structural coverage with reduced overhead, effectively decoupling resolution requirements from total RS quantity.
4Adaptability or versatility
If existing RS configurations are used, then system simplicity is maintained, but flexibility to adapt to diverse sensing scenarios is insufficient
Solution Approach 1:
The patent implements dynamic RS pattern selection where the system can adaptively choose from multiple hierarchical levels (L1, L2, L3) and different pattern types based on the specific sensing scenario requirements. The network can dynamically configure which hierarchical levels to activate and how to combine them, providing flexibility for diverse scenarios such as short-range high-resolution sensing or long-range coverage while managing complexity through standardized hierarchical building blocks.
Data Source
AI summary
Various solutions for Reference Signal (RS) transmission with respect to an apparatus in mobile communications are described. The apparatus may determine an RS pattern set. The RS pattern set may include at least one RS pattern. The at least one RS pattern may be configured using a symbol-based configuration or a slot-based configuration. The apparatus may transmit a plurality of RSs based on the RS pattern set.