MIMO Radar Self-Interference Cancellation via Segmented Transmission
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Solution Overview
Problem
Radar systems with multiple transmitters and receivers face self-interference issues, where near targets can mask out far targets due to imperfect correlation functions, particularly in phase modulated continuous wave (PMCW) systems, leading to reduced accuracy in range, velocity, and angle estimation.
Innovation Solution
A radar system that employs multiple transmitters and receivers, with a controller to manage transmission and reception modes, allowing each receiver to estimate and mitigate interference from other transmitters by correlating signals during specific operational modes, and using techniques such as Hadamard codes and FIR filters to reduce self-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple transmitters are used simultaneously to increase detection capability and spatial resolution, then the radar system can determine angular position of targets and improve detection coverage, but self-interference from multiple transmitters masks far targets and reduces measurement precision
Solution Approach 1:
The patent segments the transmission process into two distinct operational modes: a first mode where transmitters transmit sequentially one at a time to enable interference estimation, and a second mode where transmitters operate simultaneously for enhanced detection capability. This temporal segmentation allows the system to separate interference measurement from target detection, resolving the contradiction between multi-transmitter versatility and measurement precision.
Solution Approach 2:
Before executing the simultaneous transmission mode, the system performs preliminary interference estimation by sequentially activating each transmitter and measuring the resulting interference at receivers. These preliminary interference measurements are stored and then used to cancel interference during the simultaneous transmission phase, enabling far target detection without the masking effect of near targets.
2Reliability
If sequential transmission mode is used to estimate interference, then interference from each transmitter can be measured and mitigated, but the time required for interference estimation increases operational complexity
Solution Approach 1:
The patent implements periodic action by cycling through transmitters in a predetermined sequence during the first operational mode, where each transmitter is activated for a specific time interval to allow interference measurement. This periodic activation pattern enables systematic interference estimation across all transmitters in a structured manner, balancing measurement accuracy with time efficiency.
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 system effectively reduces self-interference, enhancing the detection of far targets by minimizing the impact of near targets, thereby improving the accuracy of range, velocity, and angle estimation in radar systems.
Implementation Method 1
A radar typically transmits a radio frequency (RF) signal and listens for the reflection of the radio signal from objects in the environment
Implementation Method 2
A radar typically transmits a radio frequency (RF) signal and listens for the reflection of the radio signal from objects in the environment
Implementation Method 3
Each receiver can compare a received signal with each of the possible transmitted signals. Because the received signal contains signals from various transmitters, a receiver attempting to determine the time delay from one transmitter will have interference from other transmitters
Data Source
AI summary
A radar sensing system for a vehicle includes a transmit pipeline, a receive pipeline, and a memory module. The transmit pipeline includes transmitters for transmitting radio signals. The receive pipeline includes receivers for receiving radio signals that include the transmitted radio signals transmitted by the transmitters and reflected from objects in an environment. The memory module is configured to store interference estimates for each receiver of the plurality of receivers that are estimates of interfering radio signals received by each of the receivers that are transmitted by each respective transmitter of the plurality of transmitters. Each receiver of the plurality of receivers is configured to mitigate interference that is due to interfering radio signals transmitted by the plurality of transmitters, as defined by the stored interference estimates of the plurality of transmitters for each particular receiver.