In this paper, we propose a cyclic prefix (CP) based MIMO-OFDM range reconstruction method and its corresponding MIMO-OFDM waveform design for co-located MIMO radar systems. Our proposed MIMO-OFDM waveform design achieves the maximum signal-to-noise ratio (SNR) gain after the range reconstruction and its peak-to-average power ratio (PAPR) in the discrete time domain is also optimal, i.e., 0dB, when Zadoff-Chu sequences are used in the discrete frequency domain as the weighting coefficients for the subcarriers. We also investigate the performance when there are transmit and receive digital beamforming (DBF) pointing errors. It is shown that our proposed CP based MIMO-OFDM range reconstruction is inter-range-cell interference (IRCI) free no matter whether there are transmit and receive DBF pointing errors or not. Simulation results are presented to verify the theory and compare it with the conventional OFDM and LFM co-located MIMO radars.
Index TermsMultiple-input multiple-output (MIMO) radar, orthogonal frequency-division multiplexing (OFDM), cyclic prefix (CP), zero range sidelobe, waveform design, inter-range-cell interference (IRCI) free. ).
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I. INTRODUCTIONRecently, there have been considerable interests in multiple-input multiple-output (MIMO) radar with multiple transmit and multiple receive antennas [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Unlike the conventional phased-array radar, MIMO radar transmits multiple orthogonal or orthogonal-like waveforms from multiple transmit antennas. MIMO radar is generally categorized into two types based on the distance between radar antennas, namely distributed MIMO radar [1]-[4] and co-located MIMO radar [5]- [16]. Distributed MIMO radar applies widely separated antennas to gain the spatial diversity, while co-located MIMO radar applies co-located transmit and receive antennas to improve spatial resolution. In this paper, we only consider co-located MIMO radar. Compared with the phased-array radar, co-located MIMO radar has been shown to offer many advantages such as increasing degrees of freedom and resolution [5],[6], improving parameter identifiability [7],[8], increasing sensitivity to detect slowly moving targets [9], enhancing flexibility for transmit beam pattern design [10],[11], and enhancing the capability of simultaneous tracking of multiple moving targets [12],[13].In MIMO radar, waveform design for multiple transmitters is an important and challenging issue.Generally speaking, these transmitting waveforms should satisfy the following criteria: A 1 . To reduce the interference of waveforms, the multiple transmitting waveforms should be orthogonal [14] to each other or as orthogonal to each other as possible, despite their time delays [15].A 2 . In order to obtain a maximum work efficiency of the transmitter modules, a constant envelope[16] of a transmitted time domain waveform or a low peak-to-average power ratio (PAPR) is desired.A 3 . For improving the frequency efficiency and getting a maximized signal-to-noise ratio (SNR) [17] at the rec...
