• International journal of advanced smart convergence
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• v.11 no.3
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• pp.28-35
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• 2022

Interference always exists between wireless communication systems used in the same frequency band or adjacent frequency bands. In order to deploy a new wireless communication system such as a 5G system, a new frequency band must be allocated to the system. For this purpose, after analyzing interference between the existing system and the new system, a method of setting a frequency guard band or a minimum separation distance has been used as a passive method to limit the interference effect. This paper presents a wideband RF IRM(Interference Reduction Module) that can actively reduce the influence of interference between wireless communication systems. The wideband RF IRM can reduce the interference effects of 5G signals on satellite signals. The principle and structure of the wideband RF IRM are presented. The wideband RF IRM can suppress approximately 20dB of interference signal in 100MHz bandwidth when only interference signal exists. It also shows that when a 5G interference signal of -45dBm/100MHz and a satellite signal of -55dBm/40MHz exist simultaneously at a center frequency of 3.83GHz, about 15dB of 5G interference signal can be reduced in the frequency range covered by the satellite signal. The experimental results demonstrate that the wideband RF IRM can actively reduce the 5G interference signal on the satellite signal and can be used for the purpose of reducing the interference effect in a similar environment.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.5
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• pp.527-536
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• 2021

In wireless environments, wideband receivers are used in a communication intelligent system to detect unknown signals and obtain azimuth information. To design a wideband receiver that performs multiple signal detection and direction finding simultaneously, it is necessary to consider a reception structure composed of multiple channels. In this paper, we propose a wideband multi-channel receiver for direction finding of unknown wideband communication signals including frequency hopping signals. A signal processing method for detecting received signals and estimating azimuth information is presented, and components of the manufactured wideband receiver are described. In addition, test results of the signal detection performance by mounting the proposed wideband multi-channel receiver on the flight system are included.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.164-168
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• 2008

Wideband terminal and base station is required to serve not only existing 1st and 2nd generation mobile communication systems but also 3rd generation systems. In this paper, we presents a feasibility study on single feed compact wideband antenna for wireless communication applications including GSM (890-960 MHz), GPS (1575 MHz), DCS (1710-1880 MHz), PCS (1880-1990 MHz), UMTS (1900-2200 MHz), ISM (2400-2480 MHz), IMT2000 and satellite DMB bands. The original antenna was designed for partial discharge detection sensor in high voltage diagnostic system. However, we modified the original prototype to achieve shifted down resonant frequency for wideband wireless communication applications. The experimental result shows good return loss characteristics and radiation patterns except for the total gain at each resonant frequency. The maximum measured gain was 2.45 dBi${\sim}$3.18 dBi at 1710 MHz${\sim}$1880 MHz.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.391-395
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• 2008

Wideband terminal and base station is required to serve not only existing 1st and 2nd generation mobile communication systems but also 3rd generation systems. In this paper, we present a feasibility study on coaxial feed compact wideband antenna for UHF RFID reader application. The original antenna was designed for partial discharge detection sensor in high voltage diagnostic system. However, we modified the original prototype to achieve shifted down resonant frequency for wideband wireless communication applications. The experimental result shows good return loss characteristics and radiation patterns except for the total gain at each resonant frequency. The maximum measured gain was 2.45 dBi$\sim$3.18 dBi at 910MHz.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.53-55
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• 2010

• Broadcasting and Media Magazine
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• v.19 no.1
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• pp.48-55
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• 2014

One of the recent noticeable evolutions in mobile communication systems is that wideband-codec is deployed rapidly in VoLTE (Voice over Long Term Evolution) service or HD voice. This paper is concerned with next generation HD voice or VoLTE service that is coined to describe high quality communication with super-wideband voice codec. 3GPP EVS (Enhanced Voice Service) Codec is being standardized to develop the super-wideband voice codec. This paper deals with the codec design constraints, performance requirements, the status of standardization, and finally perspective on VoLTE service in future.

• Journal of information and communication convergence engineering
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• v.7 no.4
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• pp.449-452
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• 2009

In this paper, a novel compact and wideband fylfot-shaped planar monopole antenna is proposed. The fylfot-shaped is suggested to reduce the volume of a general crossed planar monopole antenna. The volume of the proposed antenna is about 1/4 of a general crossed planar monopole antenna under the conditions where the wideband characteristics are maintained. This technique is suitable for the design of wideband planar monopole antenna which needed a small volume.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.703-715
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• 2017

In this paper, we analyze the channel characteristics of the long distance air-ground wideband common data link and we propose a mathematical method to analyze the effect of narrowband and wideband interference of air-ground channel on the received signal of wideband data link. In this paper, we analyze the reception performance according to the communication distance using the proposed performance analysis method, and found out that the communication distance is limited by the narrowband and wideband interference of ground reflection wave. As a result of the performance analysis of the method of controlling the receiving antenna upward, not only the narrow band but also the wideband interference is effectively reduced, so that the communication distance is increased even in the existing wideband data link not including the equalizer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4510-4526
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• 2017

Most available methods of facial gender recognition work well under a constrained situation, but the performances of these methods have decreased significantly when they are implemented under unconstrained environments. In this paper, a method via low-rank and collaborative representation is proposed for facial gender recognition in the wild. Firstly, the low-rank decomposition is applied to the face image to minimize the negative effect caused by various corruptions and dynamical illuminations in an unconstrained environment. And, we employ the collaborative representation to be as the classifier, which using the much weaker $l_2-norm$ sparsity constraint to achieve similar classification results but with significantly lower complexity. The proposed method combines the low-rank and collaborative representation to an organic whole to solve the task of facial gender recognition under unconstrained environments. Extensive experiments on three benchmarks including AR, CAS-PERL and YouTube are conducted to show the effectiveness of the proposed method. Compared with several state-of-the-art algorithms, our method has overwhelming superiority in the aspects of accuracy and robustness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.241-249
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• 2012

In the many countries, research about ultra wideband wireless transmission technique is widely studied for efficient utilization of frequency resource due to a sudden increase of demand of frequency resource all over the world. The ultra wideband communication system has the some specific advantages. First, it can transmit data with high speed, second short transmission range can increase the frequency reuse rate, and finally it has high security property. However, there is a interference between ultra wideband system and other communication system but study to solve this problem is insufficient. To efficient utilization of limited frequency resource, a novel frequency avoidance technique and setup the standardization of frequency interference must need. So, the purpose of this paper is that increases communication efficiency of microwave communication systems to analyze the technical trends for transmission of the low power device, and to research the implementation and technical research of wireless access network technique of wideband communication systems.