• Journal of Korea Society of Digital Industry and Information Management
• /
• v.10 no.1
• /
• pp.47-53
• /
• 2014

LTE-Advanced is the evolved version of LTE which is currently in progress at the 3GPP. At present, as the number of smart phone users is rapidly increasing, the demand for ever more capacity is driven largely by video usage and high quality data communication and so on, this let more researchers study about LTE-A all over the world. LTE-A aims to achieve improved service and communication quality over 3G system at the aspect of throughput, peak data rate, latency, and spectral efficiency. Among various features in LTE-A, the multi-user MIMO(MU-MIMO), in which the base station transmits several streams to multiple receivers, has expected to give better quality for system. In this paper, we investigate performances of various types of downlink receivers with fixed number of antennas. we first review the development process from LTE to LTE-A. Second we introduce TM9 which is adopted in Rel.10 for MU-MIMO system, including the MU-MIMO system model and the explanation on the algorithm used in system. We also have brief introduction about sub-blocking in turbo decoding, finally we compare the performance between the uncoded case and coded case which is using turbo encoding.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.12
• /
• pp.1921-1936
• /
• 2017

Internet of Thing (IoT) and NFC (Near Field Communication) have got a good adaptable structure that it can be easily combined with any wireless network. Since IoT/NFC can be used to communicate wirelessly with all the transactions that can be done remotely without any physical connections. In this paper, we propose an enhanced secure IoT/NFC protocol based on LTE network that enhances the original security level provided by the LTE. Our approach is new in a sense that it covers LTE in contrast to old networks like GSM and 3G, which substantially treated in the literature. Moreover, both GSM and 3G have several drawbacks when they are combined with the NFC technology, which has potential weakness in confidentiality, integrity, and authentication. Hence our new approach will resolve the security of the new LTE system. We expect that our protocol will result in new secure applications for the smart phone markets.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.8C
• /
• pp.741-749
• /
• 2012

Since introduction of smart phone in Korean mobile telecommunication market, mobile internet service market has changed dramatically. Although there have been many heated discussion of pro and cons of recent tremendous growth of mobile traffic, mobile data service market has contributed to re-development of whole telecommunication market. This paper is aimed at empirically test and confirms the occurrence of induced demand resulted from LTE service launching. In conclusion, we suggest the direction of regulation and policy for sustainable development of mobile internet service.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.1
• /
• pp.147-154
• /
• 2017

This paper aims to build a home security system based on IoT to monitor a home on a mobile phone. The system consists of data gathering sensors, camera, gateway and Xively platform. The Raspberry Pi collects data from the three sensors and sends the data to Xively, and sends the video stream of home to a client in a smart phone through a internet. The servers are composed of Xively, socket server in Raspberry Pi and E-mail server in Google. The proposed system transmits e-mail, text message, and video stream when there are motion, fire, and gas leakage, and can control the gas valve through Raspberry Pi. The experimental results show that a user gets 'emergency E-mail' and text message and watches the video stream of the home through WIFI or LTE on a smart phone.

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

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.1143-1144
• /
• 2013

최근 스마트폰의 보급률 증가와 3G폰에서 LTE폰으로 구입 교체할 의향을 가진 사람들이 많다. LTE 스마트폰 이용자는 전체 스마트 폰 이용자의 44.6%로 사용자가 계속 증가한 반면, 3G 스마트폰 이용자는 감소하고 있는 것으로 나타났다. 본 논문에서는 새로 스마트폰을 구입하거나, 3G 스마트폰에서 LTE 스마트폰으로 교체하는 사람들을 대상으로 웹에서 사용자의 나이, 직업, 선호 브랜드, 용도에 알맞은 스마트폰을 추천해주는 시스템을 제안한다.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.14 no.3
• /
• pp.11-20
• /
• 2018

Smart devices refer to various devices and control equipment such as health care devices, imaging devices, motor devices and wearable devices that use wireless network communication (e.g., Wi-fi, Bluetooth, LTE). Commercial services using such devices are found in a wide range of fields, including home networks, health care and medical services, entertainment and toys. Studies on smart devices have also been actively undertaken by academia and industry alike, as the penetration rate of smartphones grew and the technological progress made with the fourth industrial revolution bring about great convenience for users. While services offered through smart devices come with convenience, there is also various security threats that can lead to financial loss or even a loss of life in the case of terrorist attacks. As attacks that are committed through smart devices tend to pick up where attacks based on wireless internet left off, more research is needed on related security topics. As such, this paper seeks to design an access control method for reinforced security for smart devices. After registering and authenticating the smart device from the user's smart phone and service provider, a safe communication protocol is designed. Then to secure the integrity and confidentiality of the communication data, a management process such as for device renewal or cancellation is designed. Safety and security of the existing systems against attacks are also evaluated. In doing so, an improved efficiency by approximately 44% compared to the encryption processing speed of the existing system was verified.

• Journal of Digital Convergence
• /
• v.12 no.11
• /
• pp.133-139
• /
• 2014

This study has designed the system that can manage the amount of exercise required for health management, viewing the health management courses which are currently being operated, register the desire courses and verifying the registered schedules and monthly health performances at a glance by using a mobile application. The advantage of health club management system is automatically transmits the daily exercise information to the server without a separate sensor through a simple QR scanning using a smart phone. Since the overall operating requirements of services and various facilities of health club is transmitted as the data to the remote server through a smart phone, users of various levels including workers, students, housewives, etc can easily access and use the health club management system using the WiFi, LTE, 3G, etc.

• Journal of Korea Multimedia Society
• /
• v.21 no.3
• /
• pp.415-422
• /
• 2018

Advances of telecommunication technology bring various changes in journalism field. Reporters started to gather, edit, and transmit content to main server in media company using hand-held smart media and notebook computer. This paper tried to testify valid bit-rate of visual news content using LTE network and mobile phone. Field news like natural disasters need real-time transmission of video content. But broadcasting company normally use heavy ENG system and transmission satellite trucks. We prepared and experimented different types of visual content that has different bit-rates. Transmission tool was LU-60HD mobile system of LiveU Corporation. Transmission result shows that bit-rate of 2Mbps news content is not suitable for broadcasting and VBR (Variable Bit Rate) transmission has better definition quality than CBR (Constant Bit Rate) method. Three different bit-rate of VBR transmission result shows that 5Mbps clip has better quality than 1Mbps and 3Mbps. The higher bit-rate, the better video quality. But if the content has much movements, that cause delay and abnormal quality of video. So optimizing the balance between stability of signal and quality of bit-rate is crucial factor of real-time broadcasting news gathering business.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.1
• /
• pp.83-91
• /
• 2014

The passive UHF RFID tags for item-level tagging are now explosively used in the supply chain and retail applications as they have several advantages, the two most relevant are cost and a longer read range. However, the signal interference problem between RFID tags and smart devices in real world is expected according to the smart-phone and tablet market growth together. The performance of RFID tags can be significantly less. The popular examples are the read-success rates and read range reduction. Especially, KT Corp. recently emphasized the serious signal interference at 900 MHz of LTE and old RFID frequencies through their public demonstration. By popular demands, this paper suggests the interference tolerance measurement method between the passive UHF RFID tag and the transmitted signal from a smart device. In addition, we selected three passive UHF RFID tags(Inlay) available on the market and quantitatively evaluated read range reduction results by interference signals using the PCR(Performance Change Rates) index. As a result, the LTE system is about three times as effective as the WCDMA system in terms of interference effects, and the read range performance of two RFID tags about 60 % drop.