• Journal of Satellite, Information and Communications
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• v.3 no.2
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• pp.7-12
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• 2008

The study discussed the link analysis for the Ka band satellite broadcasting service in Korea with respect to the transmission schemes based on the DVB-S2 standard. To analyze the effect of the rain fading to the link budget, we estimated the rain attenuation from the measured rainfall intensity in Korea. We analyzed the link budget for the Ka band transponders of Koreasat-3, and DirecTV BSS-99W, and showed the possible link availability with the DVB-S2 transmission schemes for each transponder. Based on the link analysis of the available satellites with the Ka band transponders, we suggested the required EIRP for the satellite which will be employed for the Ka band satellite broadcasting service in Korea.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.51
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• pp.441-464
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• 2011

It is childhood yet in uTradeHub system practical use. According as company's necessity of cost-saving is increased according to trade terms aggravation such as uncertainty of international money market, commodities prices rise, necessity of e-trade practical use in company is increased. Use is inevitable by state that link with e-Nego and e-B/L service with related presentation e-L/C banks is not made. At the present users are doing specification only service this main point, and practical use activation through public information and marketing about service is needed situation because most of, companies which is not using service, do not know about existence availability of uTradeHub system, usage, availability. This study presented five such as early materialization of user center's link and integration, medium and small enterprises e-trade participation extension, utilization ratio raising through government's public information, e-trade cooperation business activation between the country, electronic documents standardization etc. by prompting competition about practical use of uTradeHub system.

• The Journal of Engineering Research
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• v.7 no.1
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• pp.53-60
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• 2005

Community Wireless Networks define the next generation wireless services. Multimedia usages for financial services over community Wireless LAN (WLAN) based mesh networks require link stability. Several new services are being proposed for multimedia over WLANs. Portable Internet Services are implemented by several wireless carriers to proliferate their customer base. However, these services are still expensive and require a central telecom/wireless carrier whose monopoly and preference defines the availability of new services. Our research project identifies the usage of these critical services in public places over the financial services backbone architecture to provide efficient easy-to-use and economical services to their customers and merchants without being dependent on the central wireless carrier. The user connects to the network using his regular WLAN NIC using the Mesh Router/Bridge interconnectivity and obtains the needed multimedia and financial services from the ATM-AP Gateway, In our proposed scenario, the ATN AP-MR use AODV protocol and MR-MC is based on 802.11g/a/b IEEE standard. We use multi path routing protocols for reducing the congestion over a particular route. We demonstrate the results of our simulations and test-bed outcome to evaluate link failure rate and oversubscription factors to eliminate network congestion and non-availability of the critical financial services.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.89-98
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• 2010

In this paper, the technical analyzing methodology has been suggested to preserve the same transmission quality of a M/W system used for FM broadcasting link after the frequency reallocation. The simulation was also performed for the actual M/W system operating in each frequency band, and its results were evaluated in terms of an availability based upon a fade margin. It was confirmed that only if the relative fade margin of more than 2.6 dB at 1700 MHz is provided, the equivalent service quality may be obtained regardless of the frequency reallocation. The suggested method will be expected to be widely used for accessing service quality of the M/W system concerned with the frequency reallocation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.489-498
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• 2003

Recently to introduce new services of ultra-high speed wireless access and systems beyond the 3rd generation mobile communication, 5 GHz band has been highly interested. As a way of getting the required frequency, it is considered that microwave relay bands below 6 GHz, which shows a slow decrease in demand and less cost-effectiveness, should be moved to other bands above 6 GHz. In this paper, as a tool for analyzing microwave link design and its service quality, the outage prediction based upon Vigants & Barnett＇s model is reviewed. To show outage and availability calculation, simulations are performed for the operating 4 GHz radio sites, and some results and features regarding frequency movement to 6.7 as well as 8 GHz are also discussed in terms of diversity techniques, bit error rate, and availability As the results, it is confirmed that only the diversity techniques of space or space and frequency can satisfy the annual objective of availability irrespective of frequency movement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.85-87
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• 2012

This paper, UAVs of the secondary communication link that applies to the analysys of time-division communication system and communication method proposed algorithm has been developed. UAVs of the important characteristics of the data link latency and throughput, the frequency is availability, weight. The data needed to operate UAVs vehicle control data, status data, there is an acquisition. Control and data acquisition will require real-time communication. Based on the requirements being applied to the secondary communication link communication method were compared and analyzed. The results of analysis of ground-base TDD method is suitable.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.1
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• pp.45-54
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• 1993

Monitoring processor in a circuit switched network is considered. Monitoring processor monitors communication links offers a grade of service in each link to controller. Such an information is useful for an effective maintenance of system. Two links with asymmetric system parameters and multi-symmetric links are respectively considered. Each links is to be an independent M /M/ 1/ 1/ type. Markov modeling technique is used to represent a model of monitoring processor with FCFS steering protocol. Performance measures considered are ratio of monitored jobs in each link, availability of minitoring processor and throughput of virtual processor in each link. The value of the performance meausres are compared with existing and simulation results.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.82-85
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• 2012

In this paper, we present the forward link ACM method to improve the link availability and system throughput. Also, we compare the prediction algorithm between slope based prediction and LMS algorithm. The simulation results show that the 99% of predicted values in LMS algorithm is within 3dB and that of predicted values in the slope based prediction method is within 4.5dB.

• International Journal of Contents
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• v.2 no.2
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• pp.10-16
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• 2006

In this paper, we propose a predictive resource metric region (RMR) based radio resource metric estimation (RRME) mechanism, which utilizes a resource metric mapping function (RMMF), both of which permit efficient inter-working between the physical layer and higher layers for envisaging multimedia service applications over a CDMA communication system platform. The RMR can provide the acceptable resource region where QoS and acceptable link quality can be guaranteed with an achievable resource margin to be utilized in terms of capacity margin, the degree of confidence (DCL) of user, second-order statistics of Eb/Io. With predicted capacity margin and variance, DCL can deliver decision parameters with which an adaptive QoS based admission control can perform well taking capacity and resource availability into account in a dynamic and predictive manner. Combined with advanced techniques such as adaptive modulation or rate control and power control, the proposed mechanism can adjust the conventional stringent link quality information efficiently, and deliver accurate information of the resource availability. Thus, these can guarantee the maximization of resource utilization of multimedia service applications.

• Journal of Communications and Networks
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• v.4 no.3
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• pp.161-169
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• 2002

Ad hoc wireless networks involving large populations of scattered communication nodes will play a key role in the development of low power, high capacity, interactive, multimedia communication networks. Such networks must support arbitrary network connections and provide coverage anywhere and anytime. This paper partitions such arbitrarily connected network architectures into three distinct groups, identifies the associated dual network architectures and counts the number of network architectures assuming there exist N network nodes. Connectivity between network nodes is characterized as a random event. Defining the link availability P as the probability that two arbitrary network nodes in an ad hoc network are directly connected, the network connection probability $ \integral_n$(p) that any two network nodes will be directly or indirectly connected is derived. The network connection probability $ \integral_n$(p) is evaluated and graphically demonstrated as a function of p and N. It is shown that ad hoc wireless networks containing a large number of network nodes possesses the same network connectivity performance as does a fixed network, i.e., for p>0, $lim_{N\to\infty} Integral_n(p)$ = 1. Furthermore, by cooperating with fixed networks, the ad hoc network connection probability is used to derive the global network connection probability for hybrid networks. These probabilities serve to characterize network connectivity performance for users of wireless ad hoc and hybrid networks, e.g., IEEE 802.11, IEEE 802.15, IEEE 1394-95, ETSI BRAN HIPERLAN, Bluetooth, wireless ATM and the world wide web (WWW).