93 research outputs found
Beampattern Design in Non-Uniform MIMO Communication
In recent years and with introduction of 5G cellular network and
communication, researchers have shown great interest in Multiple Input Multiple
Output (MIMO) communication, an advanced technology. Many studies have examined
the problem of designing the beampattern for MIMO communication using uniform
arrays and the covariance-based method to concentrate the transmitted power to
the users. However, this paper aims to tackle this issue in the context of
non-uniform arrays. Previous authors have primarily focused on designing the
transmitted beampattern based on the cross-correlation matrix of transmitted
signal elements. In contrast, this paper suggests optimizing the positions of
transmitted antennas along with the cross-correlation matrix. This approach is
expected to produce better results
Properties of the MIMO radar ambiguity function
MIMO (multiple-input multiple-output) radar is an emerging technology which has drawn considerable attention. Unlike the traditional SIMO (single-input multiple-output) radar, which transmits scaled versions of a single waveform in the antenna elements, the MIMO radar transmits independent waveforms in each of the antenna elements. It has been shown that MIMO radar systems have many advantages such as high spatial resolution, improved parameter identifiability, and enhanced flexibility for transmit beampattern design. In the traditional SIMO radar, the range and Doppler resolutions can be characterized by the radar ambiguity function. It is a major tool for studying and analyzing radar signals. Recently, the ambiguity function has been extended to the MIMO radar case. In this paper, some mathematical properties of the MIMO radar ambiguity function are derived. These properties provide insights into the MIMO radar waveform design
Hybrid Beamforming With Sub-arrayed MIMO Radar: Enabling Joint Sensing and Communication at mmWave Band
In this paper, we propose a beamforming design for dual-functional
radar-communication (DFRC) systems at the millimeter wave (mmWave) band, where
hybrid beamforming and sub-arrayed MIMO radar techniques are jointly exploited.
We assume that a base station (BS) is serving a user equipment (UE) located in
a Non-Line-of-Sight (NLoS) channel, which in the meantime actively detects
multiple targets located in a Line-of-Sight (LoS) channel. Given the optimal
communication beamformer and the desired radar beampattern, we propose to
design the analog and digital beamformers under non-convex constant-modulus
(CM) and power constraints, such that the weighted summation of the
communication and radar beamforming errors is minimized. The formulated
optimization problem can be decomposed into three subproblems, and is solved by
the alternating minimization approach. Numerical simulations verify the
feasibility of the proposed beamforming design, and show that our approach
offers a favorable performance tradeoff between sensing and communication.Comment: 5 pages, 2 figures, submitted to ICASSP 201
Fast Implementation of Transmit Beamforming for Colocated MIMO Radar
Multiple-input Multiple-output (MIMO) radars benefit from spatial and waveform diversities to improve the performance potential. Phased array radars transmit scaled versions of a single waveform thereby limiting the transmit degrees of freedom to one. However MIMO radars transmit diverse waveforms from different transmit array elements thereby increasing the degrees of freedom to form flexible transmit beampatterns. The transmit beampattern of a colocated MIMO radar depends on the zero-lag correlation matrix of different transmit waveforms. Many solutions have been developed for designing the signal correlation matrix to achieve a desired transmit beampattern based on optimization algorithms in the literature. In this paper, a fast algorithm for designing the correlation matrix of the transmit waveforms is developed that allows the next generation radars to form flexible beampatterns in real-time. An efficient method for sidelobe control with negligible increase in mainlobe width is also presented
Robust Design of Transmit Waveform and Receive Filter For Colocated MIMO Radar
We consider the problem of angle-robust joint transmit waveform and receive
filter design for colocated Multiple-Input Multiple-Output (MIMO) radar, in the
presence of signal-dependent interferences. The design problem is cast as a
max-min optimization problem to maximize the worst-case output
signal-to-interference-plus-noise-ratio (SINR) with respect to the unknown
angle of the target of interest. Based on rank-one relaxation and semi-definite
programming (SDP) representation of a nonnegative trigonometric polynomial, a
cyclic optimization algorithm is proposed to tackle this problem. The
effectiveness of the proposed method is illustrated via numerical examples.Comment: 6 pages, 13 figures, part of this work was submitted to IEEE Signal
Processing Letters; (short introduction; typos corrected; revised statement
in section III-B and IV; revised figure labels
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