Radar Self-Interference Reduction via Channel Precoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radar systems face self-interference issues due to the close proximity of transmitters and receivers, leading to misidentification or misdetection of objects.
Innovation Solution
The radar system operates in two modes: calibration and sensing. In the calibration mode, it estimates channel responses by transmitting test signals and receives responsive signals. These estimated channel responses are then used in the sensing mode to precode transmitted signals, reducing self-interference effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the radar system transmits signals at high power to improve detection range and accuracy, then the detection capability is improved, but self-interference increases causing false detections
Solution Approach 1:
The system performs channel estimation and precoding matrix calculation before actual radar detection. By pre-characterizing the self-interference channel and computing precoding matrices that nullify interference, the system prepares countermeasures in advance, allowing high-power transmission without suffering from self-interference during detection
Solution Approach 2:
The precoding matrix is designed to pre-cancel self-interference by applying weighted combinations of transmitted signals that create destructive interference for the direct coupling path. This preliminary anti-action occurs at the signal transmission stage, preventing self-interference from reaching the receiver before it can corrupt the detection process
2Device complexity
If the radar system uses close proximity of transmitter and receiver to reduce device size, then device complexity is reduced, but self-interference increases causing misdetection
Solution Approach 1:
The system changes the signal parameters by applying precoding matrices that modify the transmitted signal characteristics. This allows the same physical configuration (close transmitter-receiver proximity) to operate reliably by transforming the signal space to eliminate self-interference paths while maintaining the compact form factor
3Measurement precision
If the radar system transmits test signals for channel estimation, then self-interference reduction is achieved, but additional time and energy are consumed
Solution Approach 1:
The system performs channel estimation periodically rather than continuously, updating precoding matrices at intervals or when environmental changes are detected. This periodic calibration approach balances the need for accurate self-interference cancellation with the cost of time and energy consumption, maintaining detection accuracy while minimizing overhead
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A radar system operates in two modes: a calibration mode and a sensing mode. In the calibration mode, the radar system sends a set of test signals via a set of transmitters and receives responsive signals at a corresponding set of receivers. Based on the received signals, the radar system estimates the channel responses. In a sensing mode of operation, the radar system transmits a signal, receives a responsive set of signals at the receivers, and detects characteristics of nearby objects based on the received signals. In the sensing mode, the radar system employs the estimated channel responses to precode the signals for transmission and thereby reduces the components of the received signals that are due to self-interference.