Multi-Antenna Signal Transmission With Phase-Separated Doppler Bands
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Solution Overview
Problem
In radar systems with multiple transmit antennas, overlapping Doppler frequencies occur when multiple targets are at the same distance, leading to signal quality degradation during target detection.
Innovation Solution
A signal transmission method that modulates signal sequences based on different phases, distributing Doppler frequencies across equally spaced Doppler frequency bands, with a target periodic autocorrelation sidelobe value controlled to a predefined threshold, reducing overlapping Doppler frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple transmit antennas transmit signal sequences with Doppler frequency division multiplexing, then target detection capability is improved, but overlapping Doppler frequencies occur when multiple targets are at the same distance, degrading signal quality
Solution Approach 1:
The patent segments the Doppler frequency spectrum into multiple distinct bands and assigns different signal sequences from multiple transmit antennas to different segments. By distributing signals across separated frequency bands rather than allowing them to overlap, the system maintains high target detection capability while preventing signal quality degradation from frequency overlap.
2Adaptability or versatility
If multiple signal sequences are transmitted by multiple transmit antennas, then detection coverage is improved, but Doppler frequencies of different echo sequences overlap at the same Doppler frequency point, causing frequency band crosstalk
Solution Approach 1:
The patent resolves frequency band crosstalk by transitioning from a one-dimensional frequency overlap problem to a multi-dimensional solution space. It introduces both frequency band dimension (dividing spectrum into multiple bands) and spatial dimension (using multiple transmit antennas with specific phase relationships), allowing the system to achieve wide detection coverage while eliminating harmful frequency overlaps through orthogonal signal design across these dimensions.
3Reliability
If Doppler frequencies are distributed across multiple frequency bands, then overlapping is reduced, but system complexity increases due to phase modulation requirements
Solution Approach 1:
The patent manages system complexity by carefully controlling and optimizing the phase modulation parameters. Instead of arbitrary phase relationships, it establishes specific phase difference patterns between signals from different transmit antennas that are mathematically designed to achieve orthogonal separation in the frequency domain. This parameter optimization reduces the computational burden and hardware complexity while maintaining effective overlap reduction.
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 method effectively controls the quantity of overlapping Doppler frequencies, improving signal quality and accuracy of target speed estimation by ensuring each Doppler frequency is distinct, thereby enhancing the reliability of target detection.
Implementation Method 1
The W signal sequences are sequences obtained through modulation based on different phases
Implementation Method 2
target speed estimation is implemented based on a Doppler frequency of the echo sequence
Data Source
AI summary
The present disclosure relates to signal transmission methods, apparatuses, and systems. In one example method, W transmit antennas included in a transmit antenna array transmit W signal sequences. The W signal sequences are sequences obtained through modulation based on different phases. Doppler frequencies corresponding to the W signal sequences are located on N equally spaced Doppler frequency bands, and occupy W Doppler frequency bands in total. In addition, a target periodic autocorrelation sidelobe value λ of a code value of the W Doppler frequency bands is less than or equal to a predefined threshold.