D2D Reference Signal Mapping for High-Doppler Channel Estimation
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Solution Overview
Problem
In high-speed D2D communication scenarios, such as V2X, the accuracy of channel estimation is reduced due to high Doppler frequencies, and increasing the time density of DM-RS to compensate for this can decrease data throughput and error correction performance.
Innovation Solution
A user device dynamically selects between two mapping configurations for reference signals based on speed or instructions, either maintaining current density or increasing it for high-speed scenarios, and adjusts parameters to minimize interference and maintain throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the time density of DM-RS is increased to compensate for high Doppler frequency, then channel estimation accuracy is improved, but data throughput and error correction performance decrease
Solution Approach 1:
The patent applies dynamics by making the DM-RS configuration adaptable to different mobility scenarios. The system dynamically selects between first configuration (for low-speed scenarios) and second configuration (for high-speed scenarios with high Doppler frequency), allowing the DM-RS time density to be adjusted based on actual channel conditions rather than being fixed. This resolves the contradiction by enabling high channel estimation accuracy only when needed for high-speed communication.
Solution Approach 2:
The patent changes the parameter of DM-RS time density based on the Doppler frequency condition. When high Doppler frequency is detected (indicating high-speed movement), the system switches to the second configuration with increased DM-RS time density. When Doppler frequency is low, it uses the first configuration with lower DM-RS time density. This parameter adaptation resolves the contradiction by optimizing the balance between channel estimation accuracy and data throughput according to actual communication conditions.
2Measurement precision
If the time density of DM-RS is increased to compensate for high Doppler frequency, then channel estimation accuracy is improved, but error correction performance decreases
Solution Approach 1:
The system dynamically adjusts DM-RS configuration based on mobility conditions. For high-speed scenarios with high Doppler frequency, it switches to the second configuration that provides higher channel estimation accuracy. For low-speed scenarios, it uses the first configuration that preserves more resources for error correction. This dynamic adaptation resolves the contradiction between channel estimation accuracy and error correction performance.
Solution Approach 2:
The patent changes the DM-RS time density parameter according to the Doppler frequency condition. By switching between two configurations, it optimizes the trade-off between channel estimation accuracy (needed for high-speed) and error correction performance (needed for low-speed), resolving the contradiction through conditional parameter adjustment.
3Device complexity
If a fixed DM-RS configuration is used, then system complexity is reduced, but adaptability to different speed scenarios deteriorates
Solution Approach 1:
The patent implements a dynamic configuration system that adapts to different speed scenarios. The system includes a determining module that detects mobility conditions and a selecting module that chooses between first and second DM-RS configurations. This dynamic approach maintains low complexity by offering only two predefined configurations while achieving high adaptability through conditional selection based on Doppler frequency or RRC signaling.
Solution Approach 2:
The patent creates a universal DM-RS configuration system that serves multiple functions: it works for both low-speed and high-speed scenarios, adapts to different Doppler frequency conditions, and can be controlled by either autonomous determination or base station signaling. This multi-functionality resolves the contradiction by making a single system capable of handling diverse scenarios without requiring completely separate configurations for each case.
Data Source
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AI summary
A user device for a radio communication system supporting D2D communication includes a selector that selects whether to transmit a D2D signal by mapping a reference signal to a physical channel according to a first mapping configuration or to transmit the D2D signal by mapping the reference signal to the physical channel according to a second mapping configuration where the reference signal is mapped to more symbols than in the first mapping configuration, and a transmitter that transmits the D2D signal by mapping the reference signal to the physical channel according to the first mapping configuration or the second mapping configuration based on the result of the selection by the selector.