Intra-Pulse Modulation Recognition for Fractional Bandlimited Signals Based on a Modified MWC-Based Digital Receiver

Xiaomin Li,Haichao Luo,Huali Wang

doi:10.1109/access.2020.2991990

Abstract

In this paper, we present a modified modulated wideband converter (MWC)-based digital receiver for fractional bandlimited signals, and further propose an intra-pulse modulation recognition method in discrete time fractional Fourier domain (DTFrFD) for the intercepted signals. The proposed digital receiver can move the cross-channel signal to the baseband and since the nonzero part of its available spectrum is narrower in DTFrFD than in discrete time Fourier domain (DTFD), so a better separation can be achieved by the proposed digital receiver than by original MWC- based receiver. Then, with the data acquired from the digital receiver, we propose an intra-pulse modulation recognition method based on the optimal transformation order and the spectral kurtosis (SK) in DTFrFD for the six types of fractional bandlimited signals. In this algorithm, the optimal transformation order is tested to distinguish the encoded signals from the non-encoded signals, and then the SK is tested to determine the intra-pulse modulation type specially. The computational complexity of the proposed method is much lower than search-based methods. Meanwhile, since the SK of Gaussian signals is zero in DTFrFD, the proposed method shows better robustness than the original MWC discrete compressive sampling structure against SNR variation. Simulation results confirm the obtained analytical results.

Highlights

In this paper, we present a modified modulated wideband converter (MWC)-based digital receiver for fractional bandlimited signals by extending the multichannel compressed sampling structure in [27], and further suggest an intra-pulse modulation recognition method in discrete time fractional Fourier domain (DTFrFD) for the fractional bandlimited signals which is intercepted by the new receiver
This paper introduces a MWC-based digital receiver architecture in DTSFrFD to intercept fractional bandlimited signals and propose an intra-pulse modulation recognition method in DTSFrFD for the fractional bandlimited signals which is intercepted by the new receiver
The original MWCbased receiver structures are confined to stationary signal and require a high signal to noise ratio (SNR), the proposed structure in this paper overcomes the confine by taking advantage of the properties of Fractional Fourier transform (FrFT), and the original MWC-based receiver structure is shown to be a special case of it

Summary

INTRODUCTION

In this paper, we present a modified MWC-based digital receiver for fractional bandlimited signals by extending the multichannel compressed sampling structure in [27], and further suggest an intra-pulse modulation recognition method in DTFrFD for the fractional bandlimited signals which is intercepted by the new receiver. The cross-channel signals can be mixed to the baseband and get better separation than by original MWC-based receiver It is an important task for the proposed wideband digital receiver to recognize the intercepted fractional bandlimited signals, which could be used to choose the optimal algorithms to estimate the parameters of the signal. We propose an intrapulse modulation recognition method based on the optimal transformation order and the SK for the fractional bandlimited signals which is intercepted by the new receiver. With the change of α, the frequency axis of the SFrFT is located in different positions, and more abundant information about the frequency characteristics of the signal can be obtained compared to the FT

FRACTIONAL BANDLIMITED SIGNALS AND ITS

SYSTEM DESCRIPTION

DISCRETE TIME SIMPLIFIED FRACTIONAL FOURIER

METHOD DESCRIPTION

Findings

CONCLUSION