Frame-Based Listen-Before-Talk for FMCW Radar Interference Filtering
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Solution Overview
Problem
Existing radar systems face challenges in distinguishing interference from real targets due to indistinguishable beat frequencies, leading to unnecessary processing and resource consumption, especially in environments with multiple FMCW radar devices.
Innovation Solution
Implementing a frame-based listen before talk (LBT) procedure with synchronized time frames to strategically schedule LBT operations, ensuring interference is filtered out and reducing the number of LBT procedures, thereby optimizing resource usage and detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LBT procedures are performed continuously without frame-based scheduling, then radar devices can detect interference in real-time, but processing and power consumption increase significantly
Solution Approach 1:
The patent implements periodic LBT procedures scheduled at specific frame boundaries rather than continuous monitoring. The gNB performs LBT at defined intervals (e.g., at slot boundaries or frame boundaries), creating a periodic sampling mechanism that reduces overall processing while maintaining adequate interference detection capability for FMCW radar applications.
Solution Approach 2:
The patent segments the continuous LBT monitoring into discrete, scheduled operations at specific frame boundaries. By dividing the monitoring task into separate, time-separated LBT procedures rather than continuous operation, the system reduces processing overhead and power consumption while maintaining effective interference detection through strategic sampling at critical time points.
2Measurement precision
If LBT procedures are performed frequently to ensure accurate interference detection, then detection accuracy improves, but the number of processing operations and resource consumption increase
Solution Approach 1:
The patent performs preliminary LBT procedures at frame boundaries before scheduling actual radar transmissions. By conducting interference detection in advance at strategically chosen time points, the system ensures accurate detection of potential interferers while avoiding the need for continuous or post-transmission LBT operations, thereby improving processing efficiency.
Solution Approach 2:
The system uses the natural frame structure and timing already inherent in FMCW radar operations to schedule LBT procedures. By aligning LBT with existing frame boundaries and transmission schedules, the system leverages its own operational structure to perform detection without requiring additional independent processing resources, thereby maintaining detection accuracy while improving overall productivity.
3Length of moving object
If frame length is set equal to propagation delay for maximum range detection, then detection range is optimized, but LBT procedures cannot effectively distinguish interference from real targets
Solution Approach 1:
The patent introduces asymmetry between the frame length and the propagation delay by setting frame length to be a multiple of propagation delay (e.g., 2x, 4x, or 8x). This asymmetric relationship creates distinct time patterns that allow the system to differentiate between genuine target returns and interference signals, as interference will not consistently align with the asymmetric frame structure while real targets will maintain consistent timing relationships.
Solution Approach 2:
The patent uses the frame boundary structure as an intermediary mechanism between the propagation delay and interference detection. By introducing frame boundaries at multiples of propagation delay, the system creates a reference framework that mediates the distinction between interference and real targets, allowing reliable discrimination while maintaining the ability to detect at maximum range through the propagation delay parameter.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication and radar detection. In some aspects, a radar device may perform, at an initial listen before talk (LBT) frame boundary associated with an initial LBT frame of a plurality of LBT frames, an initial LBT procedure, wherein the initial LBT frame has a frame length that is larger than a propagation delay associated with a maximum detectable range associated with the radar device; and transmit a radar signal based at least in part on a successful result of the initial LBT procedure or an additional LBT procedure. Numerous other aspects are provided.