• Journal of Communications and Networks
• /
• v.6 no.3
• /
• pp.245-257
• /
• 2004

Driven by the growing number of the mobile subscribers, efficient channel resource management plays a key role for provisioning multimedia service in the next generation personal communication systems. To reuse limited channel resources, diminishing the coverage areas of cells seems to be the ultimate solution. Thus, however, causes more handover events. To provide seamless connection environment for mobile terminals and applications, this article presents a novel handover scheme called the intelligent channel reservation (ICR) scheme, which exploits the location prediction technologies to accurately reserve channel resources for handover connections. Considering the fact that each mobile terminal has its individual mobility characteristic, the ICR scheme utilizes a channel reserving notification procedure (CRNP) to collect adequate parameters for predicting the future location of individual mobile terminals. These parameters will be utilized by the handover prediction function to estimate the expected handover blocking rate and the expected number of idle channels. Based on the handover prediction estimations, a cost function for calculating the damages from blocking the handover connections and idling channel resources, and a corresponding algorithm for minimizing the cost function are proposed. In addition, a guard channel decision maker (GCDM) determines the appropriate number of guard channels. The experimental results show that the ICR scheme does reduce the handover-blocking rate while keeping the number of idle channels small.

• Journal of Digital Contents Society
• /
• v.6 no.2
• /
• pp.131-135
• /
• 2005

Nowadays, the demand for the wireless technology has gradually increased to support the services of high speed wired internet and also the interest of a mobile terminal convergence has increased. In the next generation, the mobile terminal could merge with the celluar phone, wireless LAN, portable internet, digital multimedia brodcasting, mobile game and sensor(smart-tag and biometrics) through the unified single user interface. Moreover, the system is supported to multi-mode at difference networks, which have variable functions and high performance for available service. Inthis paper, we investigate the minimum requirements and the core technologies of the next generation mobile terminals.

• The Magazine of the IEIE
• /
• v.29 no.9
• /
• pp.18-30
• /
• 2002

Wireless communication systems will be one of the biggest drivers of semiconductor products over the next decade. Global Positioning System (GPS) and Blue-tooth, HomeRF, and Wireless-LNA system are just a few of RF-module candidate awaiting integration into next generation mobile phone. Motivated by the generation mobile phone. Motivated by the growing needs for low-cost and multi-band/multi-function single chip wireless transceivers, CMOS technology has been recognized as a most promising candidate for the implementation of the future wireless communication systems. This paper presents recent developments in RF CMOS technology, which is classified into device technology and circuit technology and from them forecasts technology and from them forecasts technology trends in the near future.

• 한국정보통신설비학회:학술대회논문집
• /
• 2008.08a
• /
• pp.166-170
• /
• 2008

In 2006, ITU-R estimated the spectrum requirements for IMT-Advanced including IMT-2000 and its enhancements. And WRC-07 indentified four new spectrum bands for IMT system. Based on these results, there are many activities which are related with IMT system and its spectrum inside and outside of the country. This paper covers the next generation mobile telecommunication spectrum issues and outlook for the future of it.

• ETRI Journal
• /
• v.39 no.3
• /
• pp.383-389
• /
• 2017

A small dual-polarized base station antenna with a simple isolation patch is presented. A high isolation is achieved when using a shorted metallic isolation patch. The experimental results indicate that the measured impedance bandwidth of the proposed antenna is 1.72 GHz to 1.89 GHz for small cell systems and that the isolation is more than 30 dB. The proposed antenna exhibits good radiation patterns with a peak gain of 8 dBi.

• Journal of Information Technology Services
• /
• v.7 no.3
• /
• pp.215-237
• /
• 2008

As the paradigm of communications changes from technology-centered service provision to human-centric services, the future wireless communication systems is expected to be able to provide user-centric customized and optimized services. In order to cope with such paradigm shift in communications, various research activities on next generation mobile communication systems are being carried by a number of international organization and research centers to take initiative in future ubiquitous wireless communication environment. In this paper we propose a generic research and development framework consisting of four different research and development phases, a vision and strategy establishment phase, a service development phase, a service reference model creation phase and future service foresight phase. In particular, we give prospect of future ubiquitous wireless communication services covering different service areas of future life style based on our research frameworks.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.6
• /
• pp.1192-1197
• /
• 2011

Recent developments of small-size unmanned or manned mobile systems such as autonomous robots, exoskeleton or armored suits, micro air vehicles, and unmanned armored vehicles require long-lasting independent power sources of high energy and power density to support the systems' operation for up to 72 hours in the fields. Chemical batteries such as Ni-MH, Li-Ion, the current primary power sources for mobile devices, however, are not capable of providing enough power and energy density for the next generation high power mobile machines. For this reason, KIMM along with KERI and KIMS has been carrying out a 500W MTG development project under the DAPA's "Next generation military power source R&D program" since 2009. In this paper, a design process for a 500W MTG system currently being developed at KIMM is briefly described and the technical issues related to its development are addressed.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.11
• /
• pp.5673-5691
• /
• 2019

Information centric mobile network can significantly improve the data retrieving efficiency by caching contents at mobile edge. However, the cache pollution attack can affect the data obtaining process severely by requiring unpopular contents deliberately. To tackle the problem, we design an algorithm of mitigating cache pollution attacks in information centric mobile network. Particularly, the content popularity distribution statistic is proposed to detect abnormal behavior. Then a probabilistic caching strategy based on abnormal behavior is applied to dynamically maintain the steady-state distribution for content visiting probability and achieve the purpose of defense. The experimental results show that the proposed scheme can achieve higher request hit ratio and smaller latency for false locality content pollution attack than the CacheShield approach and the baseline approach where no mitigation approach is applied.

• Journal of Communications and Networks
• /
• v.10 no.3
• /
• pp.258-267
• /
• 2008

In this paper, we examine what changes the next-generation wireless communication systems will experience in terms of the technologies, services, and networks and, based on that, we investigate how the inter-cell interference management should evolve in various aspects. We identify that the main driving forces of the future changes involve the data-centric services, new dynamic service scenarios, all-IP core access networks, new physical-layer technologies, and heavy upload traffic. We establish that in order to cope with the changes, the next-generation inter-cell interference management should evolve to 1) set the objective of providing a maximal data rate, 2) take the form of joint management of power allocation and user scheduling, 3) operate in a fully distributed manner, 4) handle the time-varying channel conditions in mobile environment, 5) deal with the changes in interference mechanism triggered by the new physical-layer technologies, and 6) increase the spectral efficiency while avoiding centralized coordination of resource allocation of the users in the uplink channel.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.5A
• /
• pp.284-293
• /
• 2003

Location service is usually provided by the GPS method using satellites. In the next generation mobile communication systems which use smart antennas, location service can be accomplished using direction of arrival (DOA) estimation techniques. In this paper, we propose a DOA estimation technique for the location service of the next generation mobile communication systems and investigate the validity of the proposed technique through computer simulation. First, DOA estimation problems of distributed sources are considered using vortical and horizontal array processors which are orthogonal to each other. The DOA of the elevation angle is estimated by the vertical array processor and then that of the azimuth angle is estimated by the horizontal array processor. Finally, the procedures of the location service for specific signal sources using three smart antennas are exhibited by computer simulation to show that the proposed DOA estimation technique can be used for the location service in the next generation mobile communication systems.