MIMO Radar Doppler Code Multiplexing for Interference Mitigation
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Solution Overview
Problem
Existing automotive radar systems face challenges in effectively detecting and mitigating interference, which degrades the performance of sensors used in self-driving cars, such as acoustic and electromagnetic sensors, leading to suboptimal detection and tracking of vehicles, people, and obstacles.
Innovation Solution
Implementing Doppler code multiplexing techniques in MIMO radar systems, including selective Doppler shifting and phase shifting of transmit and receive signals, using bipolar phase codes like Barker codes, to enhance waveform orthogonality and improve radar performance without impacting unambiguous velocity or maximum range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Doppler code multiplexing is implemented in MIMO radar systems, then the peak-to-sidelobe ratio increases and interference is reduced, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by implementing selective Doppler shifting by nk bins and phase shifting corresponding to the Doppler shifted nk bins between chirps in the frame. These parameter modifications transform the radar signals to achieve improved peak-to-sidelobe ratio while maintaining system functionality
Solution Approach 2:
The patent segments the Doppler code multiplexing into distinct operations: Doppler shifting by nk bins for transmit signals, phase shifting for signal modulation, and corresponding receive signal processing. This segmentation allows complex interference mitigation to be broken down into manageable processing stages
2Measurement precision
If selective Doppler shifting is applied between chirps, then waveform orthogonality is enhanced, but the processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-applying the Doppler shift and phase shift operations during transmit signal generation. The Doppler code multiplexing is embedded in the signal transmission process itself, so that when receive signals are processed, the orthogonal structure is already in place, reducing the need for time-consuming post-processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed Doppler code multiplexing techniques enhance radar performance by increasing the peak-to-sidelobe ratio, reducing interference, and improving the accuracy of target detection and tracking in complex environments.
Implementation Method 1
a kth transmit signal in the K transmit signals may be selectively Doppler shifted by nk bins
Implementation Method 2
a phase shift corresponding to the Doppler shifted nk bins may be selectively applied between the M chirps in the frame in the kth transmit signal
Data Source
AI summary
An integrated circuit may include K transmit circuits that output K transmit signals, where K is a non-zero integer and the K transmit signals are encoded using first Doppler code multiplexing. Moreover, the integrated circuit may include L receive circuits that provide L receive signals (which may correspond to the K transmit signals), where L is a non-zero integer and the L receive signals are encoded using second Doppler code multiplexing. Note that the first and/or the second Doppler code multiplexing may be different from Doppler division multiplexing. Furthermore, the first Doppler code multiplexing may include selectively Doppler shifting a kth transmit signal in the K transmit signals by nk bins between chirps in a frame, and the second Doppler code multiplexing may include selectively Doppler shifting an lth receive signal in the L transmit signals by n1 bins between the chirps in the frame.