Phased-MIMO Radar: A Tradeoff Between Phased-Array and MIMO Radars (0908.2153v1)

Abstract: We propose a new technique for multiple-input multiple-output (MIMO) radar with colocated antennas which we call phased-MIMO radar. The new technique enjoys the advantages of MIMO radar without sacrificing the main advantage of phased-array radar which is the coherent processing gain at the transmitting side. The essence of the proposed technique is to partition the transmitting array into a number of subarrays that are allowed to overlap. Then, each subarray is used to coherently transmit a waveform which is orthogonal to the waveforms transmitted by other subarrays. Coherent processing gain can be achieved by designing a weight vector for each subarray to form a beam towards a certain direction in space. Moreover, the subarrays are combined jointly to form a MIMO radar resulting in higher resolution capabilities. The substantial improvements offered by the proposed phased-MIMO radar technique as compared to previous techniques are demonstrated analytically and by simulations through analysis of the corresponding beampatterns and achievable output signal-to-noise-plus-interference ratios. Both analytical and simulation results validate the effectiveness of the proposed phased-MIMO radar.

• The paper introduces the phased-MIMO radar, which integrates phased-array coherent processing with MIMO resolution enhancements.
• The methodology partitions the transmitting array into overlapping subarrays transmitting orthogonal waveforms to optimize SINR and reduce interference.
• The tradeoff analysis shows that adjusting subarray configurations balances coherent gain with resolution for improved multi-target detection.

Phased-MIMO Radar: An Analysis of Coherent Processing Gain and Resolution Tradeoffs

The paper "Phased-MIMO Radar: A Tradeoff Between Phased-Array and MIMO Radars" by Aboulnasr Hassanien and Sergiy A. Vorobyov presents a novel approach to multiple-input multiple-output (MIMO) radar technology, addressing the inherent rigidities and limitations faced by conventional phased-array and standard MIMO radar systems. The authors propose the phased-MIMO radar, a technique that combines the coherent processing advantages of phased-array radar with the resolution and target detection enhancements of MIMO radar.

Key Contributions and Methodology

1. Partitioning and Overlap Strategy: The phased-MIMO radar technique introduces an innovative method of array partitioning where the transmitting array is divided into multiple subarrays, which can overlap. Each subarray transmits a waveform that is orthogonal to those emitted by other subarrays. This strategy allows for coherent gain similar to that in phased-array systems, facilitating focused beamforming in specific directions.
2. Coherent Processing and Waveform Diversity: Through this method of subarray overlap and independent waveform transmission, the phased-MIMO radar maintains the high angular resolution inherent to MIMO systems while simultaneously leveraging the coherent processing gain from beamforming. This hybrid approach is mathematically supported by examining beampatterns and achievable signal-to-noise-plus-interference (SINR) ratios.
3. Tradeoff Analysis: A significant portion of the paper is dedicated to analyzing the tradeoffs between the number of subarrays, coherent processing gain, and resolution capabilities. By adjusting the number of subarrays, the radar system finds a balance between the robustness against interference and the detection capabilities for multiple targets.

Analytical and Simulation Results

The authors systematically compare the phased-MIMO radar against traditional phased-array and MIMO systems through analytical derivations and simulations. The phased-MIMO technique demonstrates superior resolution capabilities and reduced sidelobe levels, which are critical in rejecting interference. Its adaptable approach to beamforming allows for optimization in scenarios where both robustness to interference and high resolution are crucial.

Implications on Radar Systems Design

The phased-MIMO radar stands as a significant advancement in the development of radar systems, expanding the practical applications of MIMO technology. It provides a framework for designing radar systems that can achieve high resolution without sacrificing the benefits of coherent processing. The implications are noteworthy for various domains, including defense, automotive sensors, and research applications requiring precise target detection and localization.

Speculation on Future Developments

The phased-MIMO radar paves the way for further enhancements in MIMO radar technology. Future research can explore adaptive algorithms to dynamically adjust the number of subarrays and their configurations based on real-time environmental factors. Additionally, extensions of this work may incorporate robust adaptive beamforming techniques to further mitigate interference effects, potentially increasing operational robustness in multi-target scenarios.

In conclusion, the phased-MIMO radar combines and enhances the strengths found in phased-array and MIMO radars, presenting a versatile and robust solution for modern radar challenges. This approach marks a significant development towards advancing radar technology, offering improved capabilities crucial for modern applications in diverse environments.