• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1032-1039
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• 2022

In this paper, we designed and implemented a cavity bandpass filter combined with a cross-coupling equalizer structure to enhance Group delay for 5G mobile network repeater, which can replace the SAW (Surface Acoustic Wave) type bandwidth filter used in the existing mobile communication system. Using the 3D EM simulation tool (HFSS), the resonance frequency, the coupling coefficient between resonators, and external quality coefficient between resonators were calculated. Based on this, a 12th bandpass filter was constructed to have attenuation characteristics of more than 20dB at the edge end of both sides of the band with a metal cavity structure with a frequency band of 3500MHz to 3600MHz and bandwidth of 97.85MHz. The designed bandpass filter satisfies the group delay time requirement for the 5G mobile communication standard and the in-band and out-band frequency responses.

• ETRI Journal
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• v.42 no.5
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• pp.721-733
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• 2020

Recently, there is an increasing demand for ultra-low-latency (ULL) services such as factory automation, autonomous driving, and telesurgery that must meet an end-to-end latency of less than 10 ms. Fifth-generation (5G) New Radio guarantees 0.5 ms one-way latency, so the feasibility of ULL services is higher than in previous mobile communications. However, this feasibility ensures performance at the radio access network level and requires an innovative 5G network architecture for end-to-end ULL across the entire 5G system. Hence, we survey in detailed two the 3rd Generation Partnership Party (3GPP) standardization activities to ensure low latency at network level. 3GPP standardizes mobile edge computing (MEC), a low-latency solution at the edge network, in Release 15/16 and is standardizing time-sensitive communication in Release 16/17 for interworking 5G systems and IEEE 802.1 time-sensitive networking (TSN), a next-generation industry technology for ensuring low/deterministic latency. We developed a 5G system based on 3GPP Release 15 to support MEC with a potential sub-10 ms end-to-end latency in the edge network. In the near future, to provide ULL services in the external network of a 5G system, we suggest a 5G-IEEE TSN interworking system based on 3GPP Release 16/17 that meets an end-to-end latency of 2 ms.

• Journal of Satellite, Information and Communications
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• v.12 no.3
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• pp.8-14
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• 2017

In 4G mobile communication, data services of mobile communication began to be provided in earnest. As a result, services such as the internet and multimedia including the video have become the main contents in the recent wireless traffic. Accordingly, research on 5G mobile communication with higher transmission rate has been actively carried out. 5G mobile communication is expected to be based on 4G for compatibility with existing terminals. Therefore, the simulation of this paper is based on 4G and we propose a new user scheduling scheme based on the Max throughput scheduling algorithm to improve system performance. This paper derives the frequency efficiency and fairness to compare the existing user scheduling algorithm with the proposed user scheduling algorithm. The proposed scheme shows better frequency efficiency and fairness than Max throughput in all situations. This paper contributes to the research for improving the system performance of 5G mobile communication technology, and I hope that it will help some of the ongoing standardization work.

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.491-496
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• 2013

In this paper, a half-wavelength folded-slot antenna, which can be applied to RF module for 3G mobile communications by which security lights are monitored and controlled, is proposed. The proposed antenna can be regarded as modified folded-slot structure which has the size reduced to a half of conventional ${\lambda}g$ folded-slot antenna and can be placed at the ground plane edge. In spite of that, the proposed antenna still maintain the advantage of conventional folded-slot antenna that input impedance is close to $50{\Omega}$. The antenna is designed and fabricated within the upper space of $40.5{\times}10mm^2$ on $40.5{\times}62mm^2$ substrate for 3G mobile communication frequency band. The measured impedance bandwidth and antenna gain are 390 MHz and 2 dBi respectively.

• ETRI Journal
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• v.45 no.5
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• pp.781-794
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• 2023

Uncrewed aerial vehicles (UAVs) have become a vital element in nonterrestrial networks, especially with respect to 5G communication systems and beyond. The use of UAVs in support of 4G/5G base station (uncrewed aerial vehicle base station [UAV-BS]) has proven to be a practical solution for extending cellular network services to areas where conventional infrastructures are unavailable. In this study, we introduce a UAV-BS system that utilizes a high-capacity wireless backhaul operating in millimeter-wave frequency bands. This system can achieve a maximum throughput of 1.3 Gbps while delivering data at a rate of 300 Mbps, even at distances of 10 km. We also present the details of our testbed implementation alongside the performance results obtained from field tests.

• Electronics and Telecommunications Trends
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• v.37 no.3
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• pp.23-32
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• 2022

This paper provides an overview of optical transport technology for 5G mobile fronthaul. The configuration of fronthaul network is classified with dedicated fiber, passive WDM(Wavelength Division Multiplexing), active WDM, and semi-active WDM, which has its own advantages and drawbacks. Various WDM technology is applied for fronthaul transport, depending on the wavelength bands, required number of wavelength channels, configuration of fronthaul network, etc. In order to meet the increasing transport capacity, a 50/100 Gbps optical transceiver will be used in place of the present 10/25 Gbps technology. Trends will be continued to enhance the flexibility and reliability of the fronthaul optical network supporting highly advanced 5G mobile services.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.173-182
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• 2022

Healthcare organizations are overwhelmingly embracing smart value-based care strategies, which focuses on providing superior treatment at a significantly lower cost and quality of service (QoS). For these purposes, fifth generation (5G) of mobile service provides an innumerable improvement that clearly outperforms previous generations e.g., 3G and 4G. However, as with most advancements, 5G is projected to introduce new challenges, prompting the community to think about what comes next. This research was conducted to examine the most recent smart 5G technology applications and the solutions they provide to the healthcare industry. Finally, the paper discusses how the upcoming 6G technology has the potential to transform the future of healthcare sector even beyond the current 5G systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1458-1470
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• 2018

In this letter, a new dual-port Multiple-Input Multiple-Output (MIMO) antenna is introduced which has two independent signal feeding ports in a single antenna element to achieve smaller antenna volumes for the 5G mobile applications. The dual-port structure is implemented by adding a cross coupled semi-loop (CCSL) antenna as the secondary radiator to the ground short of inverted-F antenna (IFA). It is found that the port to port isolation is not deteriorated when an IFA and CCSL is combined to form a dual-port structure. The isolation property of the proposed antenna is compared with a polarization diversity based dual-port antenna proposed in the literature [9]. The operating frequency range is 3.3-4.0 GHz which is suitable for places where $4{\times}4$ MIMO systems are supposed to be deployed such as in China, EU, Korea and Japan at the band ${\times}$ (3.3 - 3.8GHz. The measured 6-dB impedance bandwidths of the proposed antennas are larger than 700 MHz with isolation between the feeding ports higher than 18 dB [1-2]. The simulation and measurement results show that the proposed antenna concept is a very promising alternative for 5G mobile applications.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.148-154
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• 2015

Reports show that global system for mobile communication (GSM) mobile phones, or two-generation (2G) mobile phones, could affect functions of pacemakers and implantable cardioverter defibrillators (ICDs). In this study, we evaluated the effects of radio frequency electromagnetic fields (RF-EMFs) emitted by wideband code division multiple access (WCDMA) mobile phones, which were third-generation (3G) mobile phones, on pacemakers and ICDs. Five pacemakers and three ICDs were subjected to in-vitro test using a ECG simulator. We used a WCDMA module (average power : 0.25 W, frequency band : 1950 MHz) instead of a real WCDMA mobile phone. To assess the effects of the WCDMA module on pacemakers and ICDs, each implantable device was placed in close proximity (within 3 mm) to the WCDMA module for 5 min. As a result, no effects were observed on the five pacemakers and three ICDs for the RF-EMFs emitted by the WCDMA module. Because WCDMA mobile phones have the higher frequency band (1800-2200 MHz) and lower power output (0.01-0.25 W) than GSM moboile phone, the RF-EMFs emitted by WCDMA mobile phones do not affect patients with pacemaker or ICD.

• Journal of the Ergonomics Society of Korea
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• v.27 no.1
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• pp.29-35
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• 2008

An estimated 1 billion mobile phone were sold globally in the year 2006. In Korea, people watch television 3.17 hours in a day. Television isn't what it used to be. Digital TV provides both interactivity and high definition. Mobile phone also transferred from 2G to 3G or 3.5G. This means the complexity of TV and mobile phone is increased, design of user interface is more difficult. Unlike the personal computer industry, TV and mobile phone industries have no standard user interface. A comparative study for user interface between TV and mobile phone is studied. User, task, system are analyzed in requirement analysis. User interface model and interaction are also analyzed between TV and mobile phone. This study provides some insights for user interface design. First, the UI designer have to consider another products because one user using one product at the same time using another products. Experience for one product affects that for another product. Second, TV and mobile phone show very similar pattern, especially interaction task and input interaction. Third, there are not sometimes optimized experience between service operator and device manufacturer. Cooperative design between them is required.