MIMO Radar Low Latency Decoding via Symbol Processing
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Solution Overview
Problem
MIMO radar systems face latency issues in decoding reflections, which limit the maximum detectable velocity due to the need to receive and process all reflections before decoding, reducing the system's ability to accurately detect high-velocity targets.
Innovation Solution
Implementing a low-latency decoding method using linear frequency-modulated continuous wave (LFM-CW) signals with a sliding window approach, where each symbol is processed on a symbol-by-symbol basis using a Hadamard matrix, allowing for decoding prior to receiving all reflections, and associating each transmit element with a unique code.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all N reflections are received before decoding, then decoding accuracy is improved, but latency increases and maximum detectable velocity decreases
Solution Approach 1:
The patent segments the decoding process into symbol-by-symbol operations instead of processing all reflections together. Each received reflection is decoded independently using the Hadamard matrix, allowing immediate processing of each symbol as it arrives, thereby reducing latency while maintaining decoding accuracy through sequential processing of complete symbol sets
Solution Approach 2:
The patent applies preliminary action by pre-computing and storing the Hadamard matrix with N columns before reception. This pre-prepared decoding matrix enables immediate processing of each received symbol without waiting for all reflections to arrive, reducing decoding latency while maintaining accuracy through the structured orthogonal codes
2Measurement precision
If TDMA scheme is used to resolve transmissions, then transmitter identification is improved, but maximum detectable velocity is reduced
Solution Approach 1:
The patent changes the identification parameter from time-based (TDMA) to code-based identification. Each transmitter is assigned a unique orthogonal code from the Hadamard matrix, and receivers identify transmitters by correlating received signals with these codes. This parameter change eliminates the velocity limitation imposed by TDMA time slots while maintaining accurate transmitter identification through code orthogonality
3Measurement precision
If code-based MIMO is used with N codes, then transmitter resolution is improved, but decoding latency increases due to waiting for all N reflections
Solution Approach 1:
The patent extracts and processes each symbol independently as it arrives, rather than extracting and processing the complete set of N reflections together. By taking out individual symbols from the reception stream and processing them immediately using the pre-computed Hadamard matrix, the system achieves transmitter resolution through code-based identification while eliminating the latency of waiting for all N reflections
Data Source
AI summary
A multi-input multi-output (MIMO) radar system and method of performing low-latency decoding in a MIMO radar system. The method includes transmitting a different linear frequency-modulated continuous wave (LFM-CW) transmit signal from each of N transmit elements of the MIMO radar system, each transmit signal associated with teach of the N transmit elements including a respective code, and receiving reflections associated with each of the transmit signals from each of the N transmit elements at each receive element of the MIMO radar system. Processing each symbol corresponding with each received reflection on a symbol-by-symbol basis is done to obtain a respective decoded signal prior to receiving all the received reflections associated with all the N transmit elements, wherein the processing includes using a Hadamard matrix with N columns in which each column is associated with the respective code transmitted by each of the N transmit elements.