• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.915-919
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• 2014

Since smart phones are widely used globally, the demand for high-speed mobile communications are increasing. To accommodate the increased communication demand, the next-generation mobile communication services such as LTE-Advanced are deployed. In the LTE-Advanced base stations, the base station schemes of Digital Unit (DU) and Radio Unit (RU) are widely used. Here, the link between DU and RU is called fronthaul link. In the current fronthaul link, a digital optical communication interface is used, which is called Common Public Radio Interface (CPRI). However, the CPRI link cannot support the increased mobile traffic efficiently. Therefore, in this paper, we investigate an alternative technology based on the Radio over Fiber (RoF) to accommodate the increased mobile traffic economically.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.517-521
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• 2018

In this paper, we designed a microstrip antenna for LTE / WLAN for wireless mobile communication high - speed communication network. The substrate of the proposed antenna is FR-4 (er = 4.3), the size is $20[mm]{\times}40[mm]$ and can be used in the frequency band of 2.77 [GHz] and 5 [GHz] Respectively. The simulation was performed using CST Microwave Studio 2014. The simulation result shows that the gain is 2.034 [dBi] at 2.77 [GHz] and 4.95 [dBi] at 5 [GHz]. The S-parameter was also found to be less than -10 [dB] (WSWR 2: 1) in the desired frequency band. The frequency bands of LTE and WLAN are widely used around the world, and the usage of the frequency is also increasing. For this reason, the dual-band antenna of LTE / WLAN is designed to help many users in a good way to use both technologies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.122-127
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• 2022

Currently, the drone is considered as a mobile base station of USN as a method to act as a base station using USN in existing LTE-M and LTE networks for data transmission in unmanned ships. Therefore, the drone, which is a mobile base station, is a sink node equipped with an LTE modem or a short-range communication modem, and can collect safety information of ship operation from the sensor node and transmit the safety information to the ship or transmit the information between the ships. As, if a short-range network is formed by using drones, it will form a communication network around unmanned ships and will be advantageous for collecting information using security and environmental sensors. In this paper, we propose a method to transmit environmental sensor data and to utilize communication between ships using drones to secure the surrounding information necessary for AI operation of unmanned ships in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.667-673
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• 2014

In a smart shipyard area, it is possible to integrate a variety of ship modules from separate sites into a final ship construction by using mobile applications. In this paper, we proposed the LTE femtocell network configuration which is applicable to sub shipyard, the traffic exchange method with shipyard headquarter and offload method to separate the general traffic. We defined the mode change in a femtocell gateway for supporting offload for general traffic between the main server in shipyard headquarter and sub shipyard, the offload data managements and message definition. We check the transmitted/received message flow in the wireless link, and consider the performance of the proposed method using state the transition diagram. It is expected that our results can improve the productivity within a smart shipyard by mobile communications and LTE femtocell network.

• Electronics and Telecommunications Trends
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• v.33 no.1
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• pp.111-122
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• 2018

In this review, several new technologies considered when providing an open service environment in a mobile communication network are described. Recently, 3GPP developed some standards related to IoT services for opening a service platform in an SCS environment based on the OSA concept in a 3GPP LTE system. Similarly, the development of a new framework is underway to allow a plurality of services to commonly use an API environment in which a service provider or client accesses a 5G mobile communication system. Extending the existing LTE SCEF concept, the standardization of the northbound API is applied in the 5G CAPIF environment. Therefore, it is possible to construct a framework that facilitates access from outside, and takes advantage of the common management of various open service environments. An open service platform environment is expected to play an important role in transforming a network with simple connectivity services into a variety of new service markets, or into a service environment that can create added value.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1223-1228
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• 2018

LTE-R(Long Term Evolution - Railway), as a mobile communication technology to support safety operation of train on high speed railway system, have to be equipped appropriately by hand-over method for high moving environment of train. In this paper, hand-over performance of LTE-R network, which is used in railway communication system, is analyzed and hand-over implementation condition is suggested with this analysis. The performance analysis of this study is carried out with computer simulation with NS(Network Simulator)-3. SINR(Signal to Interference and Noise Ratio) and RSRP(Reference Signal Received Power), and Data Rate is used for hand-over performance parameter.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.351-357
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• 2022

LTE (Long-Term Evolution, sometimes known as 4G LTE) is a wireless high-speed data communication technology for mobile phones and data terminals. The Packet Scheduler (PS) is an important component in improving network performance. Physical Resource Blocks (PRBs) are assigned to associated User Equipment by the packet scheduler (UEs). The primary contribution of this study is a comparison of the eNodeB throughput between a suggested method and the Round Robin (RR) Algorithm. The RR Algorithm distributes PRBs among all associated UEs without taking channel circumstances into account. In this research, we present a new scheduling method that takes into account the number of PRBs and associated UEs and produces higher throughput than the RR algorithm.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.1
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• pp.7-14
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• 2014

The rapid increase of mobile devices such as smart phone and smart pad have raised the needs for seamless multimedia services during moving at anytime and anywhere. Current 4G mobile devices are equipped with both 4G (LTE) and WLAN (WiFi) interfaces, and mobile services operators provide wireless Internet services using 4G network with a wider coverage and WiFi zone. Generally users prefer to use the Internet services through WLAN rather than LTE in the coverage of WLAN. However, since WLAN has a long L2 handover latency, it is difficult to support seamless services during a handover. In this paper, we proposed an efficient handover scheme based on flow mobility for WLANs to support a seamless service during handovers by using the overlaid 4G network with a wider coverage. Also, we showed the outperformance of the proposed scheme on a testbed.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.201-211
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• 2017

Wireless network using dynamic IP and mobile IP technology provides the user with convenience of access and movement. However, this causes the attacker who disguises normal user(pretending to be a regular user) to have more opportunity in regard to access and acquisition of information. This paper help the network administrator and the service provider quickly to recognize the attacker's intention to access network and service. Therefore network administrator and service provider can specify and respond the location of the attacker appropriately. To achieve above, we define an entity (W_L_M) that manages user information of WiFi and LTE network, and propose messages and procedures for attacker's location identification and alarm. The performance evaluation of this paper is based on qualitative analysis. By using the proposed method, some cost (message creation, processing and transmission) occurred but it was analyzed to be less than the total network operation cost. The proposal of this paper is a management method that utilizes existing network information and structure. This method can be used as a reference material to enhance security.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.186-188
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• 2014

In recent years, domestic as well as LTE wireless network of Wi-Fi and most used. In addition, mobile-intensive services that used mainly in our society makes it easier, SNS, application (APP), and file downloads. As such, the amount of data requested, while living at the time of mobile users will want to be safe from the earliest. And the wireless network communications mortality (3G, 4G (LTE), LTE-A) and Wi-Fi (802.11 n-2.4 G H z z H a c-5, 802.11 G), and users are mainly used in the death 4G (LTE), communication Wi-Fi, 802.11 n-2.4 GHz are used most frequently. As above, use the wireless network in order to safely and quickly developed the technology of the Li-Fi. Li-Fi light (visible light) technology to communicate with, and Wi-Fi (802.11 n-2.4 G z H) 100 times faster, LTE-A 66 times faster. However, the current Li-Fi to commercialise the big issue exists. In this paper, there are a lot of existing problems in the commercialization of Li-Fi being used in Wi-Fi, and a comparative analysis.