GI-FMCW Radar Reference Signal Design for Joint Communication-Radar Systems
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Solution Overview
Problem
Existing communication systems, particularly 5G NR, face challenges in improving radar sensing capabilities while maintaining communication efficiency, due to issues like intersymbol interference and intercarrier interference caused by large delay spreads.
Innovation Solution
The implementation of a radar reference signal (RRS) with a guard interval (GI)-frequency-modulated continuous-wave (FMCW) waveform, which configures parameters based on communication signals to enhance radar sensing performance while being compatible with communication-centric waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If communication systems use standard OFDM waveforms, then communication efficiency is maintained, but radar sensing performance deteriorates due to intersymbol interference and intercarrier interference from large delay spreads
Solution Approach 1:
The patent segments the OFDM waveform into two distinct parts: a communication portion using standard OFDM for reliable data transmission, and a radar portion using FMCW waveform for accurate sensing. This segmentation allows each part to be optimized for its specific function without compromising the other, resolving the contradiction between communication efficiency and radar sensing accuracy
Solution Approach 2:
The patent merges communication and radar functionalities into a single joint communication-radar (JCR) system that transmits a unified waveform containing both communication data symbols and radar reference signals. This merging enables simultaneous operation of both functions while managing their conflicting requirements through careful waveform design and parameter configuration
2Reliability
If a guard interval is added to reduce intersymbol interference, then communication reliability improves, but system overhead increases and radar sensing performance may deteriorate
Solution Approach 1:
The patent extracts the guard interval function from the communication portion and applies it specifically to the radar reference signals. By configuring separate cyclic prefixes for radar signals with lengths adapted to radar delay spreads rather than communication requirements, the system reduces unnecessary overhead while maintaining both communication reliability and radar performance
Solution Approach 2:
The patent changes the parameter of cyclic prefix length dynamically based on the signal type and radar configuration. Different cyclic prefix lengths are configured for different radar reference signals depending on their specific delay spread characteristics, optimizing the balance between reliability and overhead for each signal type
3Measurement precision
If FMCW waveform is used for radar sensing, then sensing accuracy improves, but compatibility with communication-centric waveforms deteriorates
Solution Approach 1:
The patent makes the waveform dynamic by allowing the system to switch between different waveform types (OFDM for communication, FMCW for radar) within the same transmission framework. The waveform characteristics can be adjusted in real-time based on whether the current transmission is prioritized for communication or radar sensing, enabling both high sensing accuracy and communication compatibility
Data Source
AI summary
Aspects presented herein may improve joint communication-radar system by providing a radar reference signal with GI-FMCW waveform. Aspects presented herein may be compatible with communication-centric waveforms and thereby may apply to UEs or network entities with minimal changes if specified. In one aspect, a wireless device transmits a set of communication signals. The wireless device configure one or more parameters associated with a set of radar reference signals for radar sensing based on the set of communication signals, each radar reference signal in the set of radar reference signals including a guard interval. The wireless device transmits the set of radar reference signals associated with the one or more parameters.