Generalized Multiplexed Waveform Design Framework for Cost-Optimized MIMO Radar

Abstract

Cost-optimization through the minimization of hardware and processing costs with minimal loss in performance is an interesting design paradigm in evolving and emerging Multiple-Input-Multiple-Output (MIMO) radar systems. This optimization is a challenging task due to the increasing Radio Frequency (RF) hardware complexity as well as the signal design algorithm complexity in applications requiring high angular resolution. Towards addressing these, the paper proposes a low-complexity signal design framework, which incorporates a generalized time multiplex scheme for reducing the RF hardware complexity with a subsequent discrete phase modulation. The scheme further aims at achieving simultaneous transmit beamforming and maximum virtual MIMO aperture to enable better target detection and discrimination performance. Furthermore, the paper proposes a low-complexity signal design scheme for beampattern matching in the aforementioned setting. The conducted performance evaluation indicates that the listed design objectives are met.

Doppler/Angle Coupling and Rejection for Slow-Time Phase Codes in MIMO Radar

“…Finally the Doppler phase terms e −j2πνrT h correspond to a pulse train with periodicity T h = N h T p , and thus create an additional superimposed ambiguity pattern with period 1/N h T p , that can be also observed in Figure 2. This phenomenon is similar to the Doppler/angle coupling that is observed for Time Division Multiplex modulations proposed in low cost MIMO radar applications [9], but is induced here by the presence of the slow-time phase code. We will see in the following that this Doppler/angle coupling has a strong impact when Doppler rejection is performed.…”

“…Time Division Multiplexed (TDM) MIMO radars [8], where the pulse transmission is switched from an antenna to the other in a random time pattern, belong to this category. Such strategies are however not efficient i n t erms o f S ignal-to-Noise Ratio since only one antenna is excited for a given pulse [9]. To limit that effect, general multiplexed waveforms have been…”

“…designed where several (at least two) antennas from the array are active during the same pulse, thus improving the SNR [9], [10]. It was shown that that particular coding scheme creates Doppler/angle coupling [9].…”

“…designed where several (at least two) antennas from the array are active during the same pulse, thus improving the SNR [9], [10]. It was shown that that particular coding scheme creates Doppler/angle coupling [9]. Another popular slow-time coding is the DDMA (Doppler Division Multiple Access) [11], that considers Doppler-offset waveforms.…”

Design of MIMO Radar Waveforms based on lp-Norm Criteria

“…In a MIMO radar system, different multiplexing schemes can be used to create zero values for cross-correlations of the transmitting waveforms, Frequency Division Multiplexing (FDM), Doppler Division Multiplexing (DDM), and Time Division Multiplexing (TDM) as some examples [4]. Currently, TDM-MIMO radars are commercialized in the automotive industry with a variety of functionalities from de-chirping and Doppler processing to angle estimation and tracking [5], [6]. However, Code Division Multiplexing (CDM)-MIMO is the next step of the industry, which can use more efficiently the available resources (time and frequency) [7].…”