• Journal of electromagnetic engineering and science
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• v.18 no.1
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• pp.58-62
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• 2018

In this study, we propose a software-defined radio-based frequency interference emulator in the space-time domain. This emulator can easily model actual interference environments because of the versatile programming capability of the universal software radio peripheral and LabVIEW. As an example of an interfering network using the contention-based multiple access scheme in the time domain, we emulate a coordinated Wi-Fi network that consists of one access point and two Wi-Fi nodes. Results show that our emulator can successfully model multiple interfering signals in the Wi-Fi network and easily adjust various space-time domain parameters.

• Journal of IKEEE
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• v.25 no.2
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• pp.252-260
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• 2021

In this paper, a method of using Software Defined Radio (SDR) is proposed for improving the accuracy of identifying two kinds of signals as Wireless Fidelity (Wi-Fi) signal and Bluetooth signal at the same frequency band of 2.4 GHz based on the time-domain signal characteristic. An SDR device was set up for collecting transmitting signals from Wi-Fi access points (Wi-Fi) and mobile phones (Bluetooth). Different characteristics between Wi-Fi and Bluetooth signals were extracted from the measured result. The SDR device is programmed with a Wi-Fi and Bluetooth detection algorithm and a collision detection algorithm to detect and verify the Wi-Fi and Bluetooth signals based on collected IQ data. These methods are necessary for some applications like wireless communication optimization, Wi-Fi fingerprint localization, which helps to avoid interference and collision between two kinds of signals.

• Journal of IKEEE
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• v.26 no.4
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• pp.568-576
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• 2022

Automatic modulation classification(AMC) is a core technique in Software Defined Radio(SDR) platform that enables smart and flexible spectrum sensing and access in a wide frequency band. In this study, we propose a simple yet accurate deep learning-based method that allows AMC for variable-size radio signals. To this end, we design a classification architecture consisting of two Convolutional Neural Network(CNN)-based models, namely main and small models, which were trained on radio signal datasets with two different signal sizes, respectively. Then, for a received signal input with an arbitrary length, modulation classification is performed by augmenting the input samples using a self-replicating padding technique to fit the input layer size of our model. Experiments using the RadioML 2018.01A dataset demonstrated that the proposed method provides higher accuracy than the existing methods in all signal-to-noise ratio(SNR) domains with less computation overhead.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.210-210
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• 2004

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.117-120
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• 2009

In this paper, a CR(Cognitive Radio) based on SDR(Software Defined Radio) is the technology combined a method selecting available frequency by recognizing surroundings with a learning algorithm continuously updating basic functions for communication and various environment parameters. Recently, as increasing demands with development of wireless communication service, CR is in the spotlight as technology using frequency resource efficiently. In order to apply CR system to the terminal and implement it, the research field to be preceded can be divided large as a hardware part and a software part. It can be also divided into RF processing and digital signal processing in the hardware part. In this paper, we look over preceding techniques required for applying CR system to the terminal, and research the forms of the terminal when they practically apply to the terminal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.5
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• pp.479-485
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• 2013

In this paper, we propose a smart farming system using the visible light communication based on the software defined radio (SDR) technology and the conventional RF radio. The proposed system can continuously monitor growth environments of the LED plant factory and automatically control the LED plant factory to keep optimal growth environments. Furthermore, by creating a database from various growth factors, the LED plant factory can be efficiently managed.

• Journal of Broadcast Engineering
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• v.24 no.3
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• pp.485-494
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• 2019

A software-driven real-time frequency de-modulator is implemented with the aid of universal-serial-bus (USB) type software defined radio dongle. An analog stereo frequency modulation (FM) broadcast signal is down-converted to the basedband analog signal then converted to digital bit streams in the USB dongle. Computer software such as Matlab, Python, and GNU Radio manipulates the incoming bit streams with the technique of digital signal processing. Low pass filtering, band pass filtering, decimation, frequency discriminator, double sideband amplitude demodulation, phase locked loop, and deemphasis function blocks are implemented using such computer languages. Especially, GNU Radion is employed to realize the real-time demodulator.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1051-1055
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• 2010

Software defined radio(SDR) technology implements wireless communication protocols as software instead of dedicated hardware. SDR enables reconfiguration of wireless communication protocols without expensive hardware modification. However, as the SDR systems are equipped with additional programmable processors, they suffer significant power dissipation. This paper proposes a novel power management technique for SDR systems, called the combined modulation and voltage scaling (CMVS). Numerical analyses were performed to evaluate the effectiveness of CMVS. The results show that CMVS minimizes power dissipation while satisfying the given data transfer rate.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.39-47
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• 1999

This paper presents the survey of technical trend in AD converters for wireless communication systems. This paper provides explanations about the performance measure of ADC in wireless communication application and the relation ship between BER versus effective resolution and sampling speed. The survey suggests that at least one step analog frequency down conversion is required for software defined radio systems due to current technological limit.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.319-321
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• 2003

IMT2000다음으로 개방형 구조를 갖는 차세대 통신 시스템(SDR: Software Defined Radio)에 적용할 수 있는 정보보안 메커니즘으로 블록암호화 알고리즘인 'SEEO'를 구현하였다. SDR의 플랫폼은 주로 프로그래머블(Progammable)한 FPGA가 DSP가 주를 이루는데. 본 논문은 이러한 SDR 시스템 대상으로 적용할 수 있는, 한국형 블록 암호 알고리즘인 'SEED'를 DSP, FPGA로 구현하고 성능비교. 분석을 통하여 효과적이고 합리적인 SDR 암호화 모듈 구현의 방향을 모색해 보았다.