Abstract

The OFDM chirp signal is suitable for MIMO radar applications due to its large time-bandwidth product, constant time-domain, and almost constant frequency-domain modulus. Particularly, by introducing the time-frequency structure of the non-linear frequency modulation (NLFM) signal into the design of an OFDM chirp waveform, a new OFDM-NLFM waveform with low peak auto-correlation sidelobe ratio (PASR) and peak cross-correlation ratio (PCCR) is obtained. IN-OFDM is the OFDM-NLFM waveform set currently with the lowest PASR and PCCR. Here we construct the optimization model of the OFDM-NLFM waveform set with the objective function being the maximum of the PASR and PCCR. Further, this paper proposes an OFDM-NLFM waveform set design algorithm inspired by alternating optimization. We implement the proposed algorithm by the alternate execution of two sub-algorithms. First, we keep both the sub-chirp sequence code matrix and sub-chirp rate plus and minus (PM) code matrix unchanged and use the particle swarm optimization (PSO) algorithm to obtain the optimal parameters of the NLFM signal’s time-frequency structure (NLFM parameters). Next, we keep current optimal NLFM parameters unchanged, and optimize the sub-chirp sequence code matrix and sub-chirp rate PM code matrix using the block coordinate descent (BCD) algorithm. The above two sub-algorithms are alternately executed until the objective function converges to the optimal solution. The results show that the PASR and PCCR of the obtained OFDM-NLFM waveform set are about 5 dB lower than that of the IN-OFDM.

Highlights

  • To design the Orthogonal frequency division multiplexing (OFDM)-non-linear frequency modulation (NLFM) waveform set with the lowest possible peak auto-correlation sidelobe ratio (PASR) and peak cross-correlation ratio (PCCR), this paper proposes an OFDM-NLFM waveform set design algorithm based on alternating optimization

  • The results show that the PASR is lower when the NLFM parameters are in the interval of a ∈ (0, 0.9), b ∈ (−0.2, 0.2)

  • The results show that the proposed algorithm based on alternating optimization can obtain the Multiple-input multiple-output (MIMO) radar OFDM-NLFM waveform set with low PASR and PCCR

Read more

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The OFDM-NLFM waveform set design algorithm based on alternating optimization is composed of two sub-algorithms; the PSO algorithm optimizes the continuous NLFM parameters, and the BCD algorithm optimizes the sub-chirp sequence code matrix and the sub-chirp rate PM code matrix. This paper develops the signal model and parameter optimization model of the OFDM-NLFM waveform set.

OFDM-NLFM
The time-frequency structure of one oftransmit
MIMO Radar Waveform Set Performance Evaluation
OFDM-NLFM Waveform Set Optimization Model
OFDM-NLFM Waveform Set Design Algorithm Based on Alternating Optimization
OFDM-NLFM Waveform Set Parameter Initialization
NLFM Parameters Optimization Based on PSO
OFDM-NLFM Waveform Set Design
The Effect of Random Initialization
The segmentation pa- The
The Effect of Time-Domain Segmentation Parameters
The Effect of MIMO System Parameters
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call