A Comprehensive Review of Quasi-Orthogonal Waveforms

Keel, Byron M.; Heath, T.

doi:10.1109/radar.2007.374202

Cited by 25 publications

(17 citation statements)

References 13 publications

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“…In the first examples, the interference to noise ratio (INR) was 20 dB. The output of the matched filter and the conventional MVDR filter given by (2) are shown in Figure 1. The filters shown are designed for receiving the first sequence in the used set of polyphase sequences, and the output of the filter for the first sequence (autocorrelation) and the second sequence (cross-correlation) are plotted.…”

Section: Numerical Examplesmentioning

confidence: 99%

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MIMO radar filterbank design for interference mitigation

Aittomaki

Koivunen

2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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MIMO radars transmit multiple waveforms simultaneously. As the number of waveforms used increases, the cross-correlation between the waveforms also tends to increase if the transmission time or bandwidth is not increased. By using a bank of mismatched filters at the receivers, it is possible to decrease the peak cross-correlation and autocorrelation sidelobe levels of the used waveforms. Furthermore, interference power can also be significantly reduced at the same time. We propose a filterbank design for the MIMO radar receiver based on minimizing the interference power at the receiver while controlling peak sidelobe and cross-correlation values, resulting in a convex optimization problem.

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Section: Numerical Examplesmentioning

confidence: 99%

“…However, it is not possible to have waveforms that are orthogonal for all time delays and Doppler shifts [2]. Optimization of transmitted waveforms for MIMO radar has been studied in many papers in an attempt to obtain waveforms as close to orthogonal as possible.…”

Section: Introductionmentioning

confidence: 99%

MIMO radar filterbank design for interference mitigation

Aittomaki

Koivunen

2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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“…Weh av e explored an ad hoc method for generating such signals. Although such sequences are wellknown [4], there are extensions of our methodology which may prove useful, e.g. finding signals with a smooth envelope and desired correlation properties.…”

Section: Application Of Pn Spreading Sequencementioning

confidence: 99%

Constant-modulus partially correlated signal design for uniform linear and rectangular MIMO radar arrays

Fuhrmann

Browning

Rangaswamy

2009

2009 International Waveform Diversity and Design Conference

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Am ethod for generating partially correlated signals that result in arbitrary rectangular transmit beampatterns in a MIMO radar system is described. These signals are computed using frequency-offset complexe xponentials (1-D) or Kronecker products of frequency-offset complexe xponentials (2-D), followed by pointwise multiplication of the transmit signal vectors by a scalar pseudo-noise spreading sequence. Except for the spreading sequence, which can be pre-computed, the signals are giveni nc losed form and thus require no numerical optimization. The transmit beampattern shape is controlled by one scalar parameter in 1-D and twoscalar parameters in 2-D. The transmit beampattern is the convolution of a rectangle with a sincsquared function in 1-D, and the separable product of such functions in 2-D. The signals are constant-modulus, have desirable temporal autocorrelation properties, and are simple to compute.

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“…A large majority of radar systems employ linearly frequency modulated (LFM) chirp signals, who have excellent properties for radar imaging, but where achieving orthogonality is not very feasible. In practice, quasi-orthogonal approaches must therefore be adopted and some interference is always left in the system [9,13,16].…”

Section: Introductionmentioning

confidence: 99%

Removal of Range Ambiguities with Orthogonal Block Coding Techniques

Akhtar

2009

Circuits Syst Signal Process

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This paper considers radar signaling schemes for cancellation of late time arriving echoes. Signal reflections arriving delayed at the radar when the radar has already emitted a next pulse result in range ambiguities and materialize as potential false targets. In this work we put forward alternative waveform encoding schemes enabling a well-defined radar system to double, triple or quadruple the pulse repetition frequency (PRF) with full suppression of emerging range ambiguities. The proposed techniques thus have the potential to overcome the contradiction often faced in radar and synthetic aperture radar setups between selecting a low or high value for the PRF. The methods introduced require only simple matched filtering operations at the receiver and permit usage of arbitrary waveforms with potential for waveform diversity gains.

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A Comprehensive Review of Quasi-Orthogonal Waveforms

Cited by 25 publications

References 13 publications

MIMO radar filterbank design for interference mitigation

MIMO radar filterbank design for interference mitigation

Constant-modulus partially correlated signal design for uniform linear and rectangular MIMO radar arrays

Removal of Range Ambiguities with Orthogonal Block Coding Techniques

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