• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.5
• /
• pp.1109-1116
• /
• 2010

In this paper, some performance characteristics of VoIP(Voice over Internet Protocol) for MANET(Mobile Ad-hoc Networks) with simulation is studied and appropriate condition for implementation of VoIP service is suggested. VoIP simulator is implemented with NS(Network Simulator)-2. VoIP traffic for simulation is generated with some codecs of G.711, G.723.1, G.726-32, G.729A, GSM.AMR and iLBC. As simulation results for traffic transmission under $670{\times}670m$ 50node MANET environment, performance data for MOS(Mean Opinion Score), network delay, packet loss rate and transmission bandwidth are measured. Normalized analysis about measured results shows that maximum VoIP connection satisfying VoIP service quality condition is 15.

• Journal of Convergence for Information Technology
• /
• v.10 no.1
• /
• pp.22-27
• /
• 2020

With the deployment of 5G infrastructure, content delivery network (CDN) will be a key role to provide explosive growing services for the independent media and YouTube which contain high-speed mobile contents. Without a local cache, the mobile backhaul and fronthaul should endure huge burden of bandwidth request for users as the increase number of direct accesses from contents providers. To deal with this issue, this paper fist presents both fronthaul solutions for CDN that use dark fibers and a passive optical network (PON). On top of that, we propose the aggregated content request specialized for PON caching and evaluate and compare its performance to legacy schemes through the simulation. The proposed PON caching scheme can reduce average access time of up to 0.5 seconds, 1/n received request packets, and save 60% of backhaul bandwidth compared to the no caching scheme. This work can be a useful reference for service providers and will be extended to further improve the hit ratio of cache in the future.

• Information and Communications Magazine
• /
• v.32 no.7
• /
• pp.40-45
• /
• 2015

네트워크 장비 업체나 통신사뿐만 아니라 여러 국가들에서도 상용화를 목표로 5G 기술 확보를 위한 대규모의 연구 개발 역량을 집결하고 있다. 이 중 대다수의 연구 개발은 SDN(Software Defined Network)과 NFV(Network Function Virtualization)를 기반으로 두고 있다. 이는 5G의 아키텍처가 동적인 네트워크를 생성하는데 초점을 맞추고 있기 때문이다. 이에 본 고에서는 METIS 2020(Mobile and wireless communication Enablers for the Twenty-twenty Information Society)에서 발표한 최종 리포트를 참고하여 5G 이동통신 네트워크에서의 SDN과 NFV의 역할에 대해 알아 보고, 현재 진행 중인 개발 행태를 보기 위해 대표 기업들의 동향을 살펴본다.

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

• Electronics and Telecommunications Trends
• /
• v.36 no.5
• /
• pp.51-61
• /
• 2021

To reduce mobile network deployment costs and expand service coverage, mobile infrastructure sharing is becoming increasingly important. This paper introduces the concept and potential benefits of mobile infrastructure sharing as documented in the existing literature. Then, the current status of significant cases of mobile infrastructure sharing in major overseas countries is examined. Finally, sharing 5G infrastructure in rural areas in Korea is introduced. The Korean case is expected to complete national 5G coverage successfully without involving negative competition.

• Electronics and Telecommunications Trends
• /
• v.31 no.1
• /
• pp.25-35
• /
• 2016

Mobile Edge Computing(MEC)은 무선 기지국에 분산 클라우드 컴퓨팅 기술을 적용하여 다양한 서비스와 캐싱 콘텐츠를 이용자 단말에 가까이 전개함으로써 모바일 코어망의 혼잡을 완화하고, 새로운 로컬 서비스를 창출하는 기술이다. 현재는 European Telecommunications Standards Institute(ETSI)주도로 규격 작업이 진행되고 있으며, 동시에 산업계에서는 LTE 모바일 네트워크에 적용하는 시도들이 이루어지고 있다. 그러나 MEC기술은 Software Defined Network(SDN)/Network Functions Virtualization(NFV) 기술들과 함께 향후 2020년대에 도입될 5G 네트워크의 주요 구성 기술로서 부상하고 있다. 본고에서는 MEC의 개념과 다양한 서비스 시나리오, MEC 플랫폼 구조 및 기술동향 등을 살펴보고, 5G에서의 역할과 앞으로 도전하여야 할 기술적인 과제들에 대하여 분석한다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.12B
• /
• pp.1099-1111
• /
• 2006

As W-CDMA R5(HSDPA) service became recently commercialized in Korea, there is increasing demand for new pricing methodology for the 3G mobile interconnection at the earliest possible time. However, it is hard to find any case of systematic study on it. In this paper, a synthetic investigation into the three aspects of new mobile telecommunication service - technology, market, and regulation - is conducted to verify the validity of new interconnection pricing methodology. As the findings of this research indicate, given the several technological limits of 3G, speed of mobile telecommunication industry evolution, the problem of verifying ex-ante regulations' validity, and the cases of some foreign countries, it is suggested that immediate revision of interconnection policy is not sensible and that the revision is more desirable to be postponed until the maturity of the 3G market or the adoption of All-IP network.

• ETRI Journal
• /
• v.38 no.6
• /
• pp.1052-1063
• /
• 2016

We propose a millimeter wave (MMW)-based mobile hotspot network (MHN) system for application in high-speed railways that is capable of supporting a peak backhaul link throughput of 1 Gbps per train at 400 km/h. The MHN system can be implemented in subways and high-speed trains to support passengers with smart devices and provide access to the Internet. The proposed system can overcome the inherent high path loss in MMW through system designs and high antenna gains. We present a simulation of the system performance that shows that a fixed beamforming strategy can provide high signal-to-interference-plus-noise-ratio similar to those of an adaptive beamforming strategy, with the exception of 15% of the train path in which the network can use link adaptation with low-order modulation formats or trigger a handover to maintain the connection. We also demonstrate the feasibility of the MHN system using a test bed deployed in Seoul subway line 8. The backhaul link throughput varies instantaneously between 200 Mbps and 500 Mbps depending on the SNR variations while the train is running. During the field trial, the smartphones used could make connections through offloading.

• Electronics and Telecommunications Trends
• /
• v.35 no.2
• /
• pp.38-49
• /
• 2020

In recent years, the unmanned aerial vehicle (UAV) assisted mobile free space optical (FSO) communication technique has attracted considerable attention regarding its aims to provide improved communication conditions for fixed-to-fixed FSO network and promising fronthaul and backhaul solutions for 5G+ wireless networks. This can be attributed to its outstanding advantages such as fast deployment and flexible network configuration. The UAV-assisted mobile FSO system can be used to provide cost-effective internet services in rural and remote areas and in hotspot areas that are characterized by increased data traffic. Additionally, it can be used to provide secure communication services under emergency circumstances. In this report, we review recent R&D trends in wireless network technology employing the UAV-assisted mobile FSO technique and key technologies for mobile FSO wireless networks. Furthermore, we introduce drone-based mobile FSO terminals and control systems that we have developed.

• ETRI Journal
• /
• v.40 no.1
• /
• pp.72-88
• /
• 2018

In the fifth generation (5G) era, the radio internet protocol capacity is expected to reach 20 Gb/s per sector, and ultralarge content traffic will travel across a faster wireless/wireline access network and packet core network. Moreover, the massive and mission-critical Internet of Things is the main differentiator of 5G services. These types of real-time and large-bandwidth-consuming services require a radio latency of less than 1 ms and an end-to-end latency of less than a few milliseconds. By distributing 5G core nodes closer to cell sites, the backhaul traffic volume and latency can be significantly reduced by having mobile devices download content immediately from a closer content server. In this paper, we propose a novel solution based on software-defined network and network function virtualization technologies in order to achieve agile management of 5G core network functionalities with a proof-of-concept implementation targeted for the PyeongChang Winter Olympics and describe the results of interoperability testing experiences between two core networks.