Compact Time-Frequency Division Multiplexing for MIMO Radar
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Solution Overview
Problem
Conventional MIMO radar systems face inefficiencies in time and frequency resource utilization due to the need for orthogonal signal transmission, leading to long pulse repetition intervals, reduced maximum unambiguous velocity, and increased frequency bandwidth requirements, which compromise radar performance and flexibility.
Innovation Solution
Implementing compact time-frequency division multiplexing in MIMO radar systems, where signals from different transmitters overlap in both time and frequency domains, allowing for more flexible waveform design and efficient resource use without compromising orthogonality, enabling higher resolution in four dimensions (elevation, azimuth, range, and radial velocity).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional time division multiplexing is used to ensure orthogonal signal transmission, then signal separability is improved, but pulse repetition interval increases and productivity deteriorates
Solution Approach 1:
The patent applies dimensionality change by transitioning from conventional time-division multiplexing to time-frequency division multiplexing. Multiple signals are transmitted simultaneously in the time domain but are separated in the frequency domain through different frequency shifts, allowing overlapping time intervals while maintaining orthogonality. This resolves the contradiction by enabling shorter pulse repetition intervals (improved productivity) while preserving signal separability through frequency-domain differentiation.
2Reliability
If conventional frequency division multiplexing is used to ensure orthogonal signal transmission, then signal separability is improved, but frequency bandwidth requirements increase
Solution Approach 1:
The patent applies parameter changes by using different frequency shift amounts for different signals rather than fixed equal spacing. The frequency shifts are configured based on the specific requirements of each signal, allowing optimized use of frequency resources. This enables signal separability to be maintained while reducing the total frequency bandwidth requirement compared to conventional equal-spaced frequency division multiplexing.
3Reliability
If longer pulse repetition interval is used to accommodate multiple transmitters, then signal orthogonality is improved, but maximum unambiguous velocity decreases
Solution Approach 1:
The patent resolves this contradiction by moving the orthogonality separation from the time domain to the frequency domain. By applying different frequency shifts to different transmitter signals, the system achieves orthogonality without requiring long pulse repetition intervals. This enables the radar to maintain high maximum unambiguous velocity while preserving signal orthogonality through frequency-domain multiplexing rather than time-domain multiplexing.
Data Source
AI summary
Methods and apparatus to implement compact time-frequency division multiplexing for MIMO radar are disclosed. An apparatus includes an antenna array controller to: transmit a first signal via a first transmitter of a radar antenna array, the first signal having a first duration and modulated across a first frequency range; and transmit a second signal via a second transmitter, the second signal having a second duration and modulated across a second frequency range, the first and second durations including an overlapping period of time, the first and second frequency ranges including an overlapping frequency range. The apparatus further includes a signal separation analyzer to: determine a first echo received at a receiver of the radar antenna array corresponds to the first signal; and determine a second echo received at the receiver corresponds to the second signal.