• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.105-108
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• 2016

In this paper, a cooperative jamming network with multiple relays and multiple eavesdroppers is investigated. Among the relays, one best relay is selected to amplify and forward the signal to destination through two phases. To confuse eavesdroppers, the destination transmits a jamming signal in the first phase and the source transmits jamming signal in the second phase. Secrecy rate of this system is derived, and based on the available channel state information (CSI), relay selection schemes are proposed, respectively. Numerical results show that the performance of the proposed relay selection scheme outperforms than that of random relay selection scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1201-1207
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• 2005

When the isolation between transmitter and receiver in Electronic Warfare equipment is not sufficient, the radiated noise jamming signal from the transmitter feeds back into the receiver and interferes with receiving radar pulse signal. Therefore pulse jamming and noise jamming can't be performed together in the same frequency bands. In this paper, we present a time-sharing TX/RX control technique of the switch matrix which inhibits the transmission of noise jamming signal by using the predicted gate of pulse train and also makes the corresponding channel filter operate to receive the radar pulse signal during the predicted gate pulse. This technique was implemented by EPLD and confirmed by experiment. The proposed technique enables the pulse jamming and the noise jamming to be simultaneously executed in multiple jamming environments.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.32-36
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• 2016

In wireless communication systems, jamming attack is a critical threat. Especially, reactive jamming can jam when the sender and receiver are communicating, which can maximize the attack efficiency of jamming. In this paper, we use the property of multi-input multi-output (MIMO) technology to achieve jamming resilient orthogonal frequency-division multiplexing (OFDM) communications. In particular, we use MIMO interference cancellation to remove the jamming signals strategically. We first investigate the reactive jamming attack model and their impacts on the MIMO-OFDM systems. We then present an iterative channel estimation algorithm that exploits MIMO interference cancellation. Our simulations show various anti-jamming methods and demonstrate the efficiency of our proposed algorithm under the reactive jamming attack.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.63-67
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• 2014

A distributed zero-beamforming based cooperative jamming technique is useless when an eavesdropper detects the sharing seed. In addition, the currently alternatives are very limited when the eavesdropper is located nearby a source for wiretapping. This letter presents a solution to this extreme case. Relay randomly generates and transmits a binary jamming message to both source and destination in the first phase. When these two receivers securely and correctly decode the message, the source creates and transmits another message based on the use of exclusive-or for its information message and the decoded message. Consequently, the next transmission can avoid the eavesdropping.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.878-883
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• 2018

A jamming design scheme to disturb target position estimation of a bistatic multiple-input multiple-output(MIMO) radar system is presented. The proposed method exploits the received signals from distributed multiple electronic sensors and combines them to produce a jamming signal. The proposed algorithm can eliminate the target by transmitting the delayed sum or the weighted sum of the received senor signals. Simulation results confirm the performance of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.7
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• pp.955-961
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• 2021

In modern warfare, the importance of electronic warfare, which carries out a mission that using radio wave to find out enemy information or to protect ally information, has increased. Radar jamming technique is one of the most representative techniques of EA(Electronic Attack), it disturbs and deceives enemy radar system in order to secure ally location information. Velocity deception jamming technique, which is one of the radar jamming techniques, generally operate against pulse-doppler radar which use doppler effect in order to track target's velocity and location. Velocity Deception Jamming Technique can be implemented using DRFM(Digital Radio Frequency Memory) that performs Frequency Modulation. In this paper, I describe implementation method of VGPO/VGPI(Velocity Gate Pull-Off/Pull-In) velocity deception jamming technique using phase-sampled DRFM, and verify the operation of VGPO/VGPI velocity deception jamming technique with board test under signal injection condition.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.197-205
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• 2017

During the sea trial, we discovered EMI between MOSCOS and ES DF antenna. CW emitted by MOSCOS raised the threshold level of ES DF antenna. As a result, direction finding rate of ES has been decreased. This is a study for the improvement of EMI between the antennas mounted on a surface ship. An analysis is accomplished for MOSCOS, ES DF antenna and Jamming transmitter. This paper presents the method how to solve EMI based on the measurements and calculations about the ES DF antenna receiving level, MOSCOS radiation pattern and Jamming transmitter thermal noise. The test was performed with optimal deployment of MOSCOS on a surface ship. After changing the position of MOSCOS, EMI has been decreased significantly.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.6
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• pp.577-580
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• 2016

One of the effective jamming methods to disturb monopulse radars is a wavefront distortion. Most well-known wavefront distortion is the cross eye technique which uses two transmitters. The cross eye can make angle error regardless of monopulse radar structure but high accuracies of phase and amplitude between two transmitters should be needed to make large angle error. Thus, the accuracies of phase and amplitude are essentially required performance parameters for implementation of wavefront distortion systems and the required values of accuracy is dependant on amount of angle error. In this paper, we derive expressions for minimum required values of phase difference and amplitude ratio according to amount of angle error and analyze the results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.146-149
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• 2018

A monopulse sensor is used to estimate the angle of a target with respect to each received single pulse. It is well known that the cross-eye technique can result in an angle deception effect against monopulse sensors. To verify this effect, we propose a test environment configuration for the angle deception using monopulse receiving antennae and cross-eye transmitters in an anechoic chamber. Using the proposed test environment configuration, we have measured powers of the sum and difference of the signals received by the monopulse receiving antennae when the distance of the two cross-eye transmitters is varied. Finally, the angle deception performance related to the powers of the sum and difference signals was analyzed.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.713-720
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• 2018

The Signal Intelligence (SIGINT) system based on Angle-of-Arrival(AOA) estimation, interference suppression, and transmission beamforming techniques is a cutting edge technology for efficiently collecting various signal information. In this paper, we present the efficient structure of a satellite system consisted of an AOA estimator, an adaptive beamformer, a signal processing and D/B unit, and a transmission beamformer, for collecting signal information. For accurately estimating AOAs of various signals, efficiently suppressing interference or jamming signals, and efficiently transmitting the collected information or data, we employ Multiple Signal Classification (MUSIC), Minimum Variance Distortionless Response (MVDR), and Minimum Mean Square Error (MMSE) algorithms, respectively. Also, we evaluate and analysis the performance of the presented satellite system through the computer simulation.