• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.285-289
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• 2020

The configuration of hierarchical wireless networks is provided to support diverse network environments. In the base station, two system state can be basically considered for the operation management so that the state transition may be occurred between active and sleep modes. Hence, to reduce energy consumption the system operation management of the low power should be considered to the base station system. In this paper we consider the analytical model of Discontinuous Reception (DRX) to investigate the system management. We provide the analysis scheme of base station system by the DRX model, and the low power factor would be investigated for the energy consumption. We also use the finite-state Markov system model that in a system state period the wireless resource request and the operation of service call arrival interval is considered to numerically analyze the performance of energy saving operations of base station.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.601-609
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• 2010

This paper measured EMF strength of the duty measurement radio station(77 station) and the non-duty measurement radio station(41 station) of mobile communication base station in Jeonbuk region. As the result of measurement, it generally reveals that EMF is highly low level compare to the human protection guideline. And It is regarded as level that the national people who live close to the mobile communication base station don't have to worry about electromagnetic wave. This paper provides comparative analyses categorized by the duty measurement station and the non-duty measurement station. The results reveals that the average value and the maximum value of the non-duty measurement station preferably was higher than all the duty measurement station. It is thought that the EMF exposure strength of the national people is caused by approach of station antenna rather than antenna power. Consequently this paper suggests that standard of the antenna power(exceed 30 W), standard of antenna height(exceed 10 m) specified by Radio Regulation Act enforcement ordinance, legal basis for mobile communication base station have to be changed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.475-488
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• 2003

To prevent performance degradation of TCP due to packet losses in the smooth handoff by the route optimization extension of Mobile IP protocol, a buffering of packets at a base station is needed. A buffering of packets at a base station recovers those packets dropped during handoff by forwarding buffered packets at the old base station to the mobile user. But, when the mobile user moves to a congested base station in a new foreign subnetwork, those buffered packets forwarded by the old base station are dropped and TCP transmission performance of a mobile user in the congested base station degrades due to increased congestion by those forwarded burst packets. In this paper, considering the general case that a mobile user moves to a congested base station, we analyze the influence of packet buffering on TCP performance according to handoff arrival distribution for Drop-tail and RED (Random Early Detection) buffer management schemes. Simulation results show that RED scheme can reduce the congestion increased by those forwarded burst packets comparing Drop-Tail, but RED scheme cannot avoid Global Synchronization due to forwarded burst packets by the old base station and new buffer management scheme to avoid it is needed in Mobile IP based networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.500-511
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• 2003

To prevent performance degradation of TCP due to packet losses in the smooth handoff by the route optimization extension of Mobile IP protocol, a buffering of packets at a base station is needed. A buffering of packets at a base station recovers those packets dropped during handoff by forwarding buffered packets at the old base station to the mobile user. But, when the mobile user moves to a congested base station in a new foreign subnetwork, those buffered packets forwarded by the old base station are dropped and the wireless link utilization performance degrades due to increased congestion by those forwarded packets. In this paper, considering the case that a mobile user moves to a congested base station in a new foreign subnetwork, we propose an Implicit Priority Packet Forwarding to improve TCP performance in mobile networks. In the proposed scheme, the old base station marks a buffered packet as a priority packet during handoff. In addition, RED (Random Early Detection) at the new congested base station does not include priority packets in queue size and does not drop those packets randomly based on average queue size. Simulation results show that wireless link utilization performance of mobile hosts can be improved without modification to Mobile IP protocol by applying proposed Implicit Priority Packet Forwarding.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.61-66
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• 2005

Location Positioning is a major technology for ubiquitous computing. Recently the research on Location Positioning using UWB is on going. In order to construct an in-door location network, synchronization of base stations is very important. NTP is Popularly used as clock synchronization protocol ranging from LAN to WAN. Also Master-Slave scheme is the simplest method to synchronize in-door network. We compare and analyze NTP and Master-Slave schemes according to the statistical channel model for indoor multipath propagation environment. In this paper, error ranges are calculated at various circumstances that in-door network expands from one primary base station into several base stations. We compared the correctness of NTP and Master-Slave synchronization methods. NTP is more reasonable synchronization protocol in in-door environment.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.4
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• pp.87-94
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• 2016

This paper proposes an energy transmission method to maximize energy efficiency of a based station. This method makes use of classification of service type to solve an inefficient use of transmission power, which is from exponential relationship between the legacy data throughput and transmission power. The proposed one is a way to find the most energy-efficiency points with the transmitted optimal amount of data on users in a base station of wireless network environment. For this, we propose EETA (Energy-Efficient Transmission Algorithm) which can control the amount of data and the holding time at the base station. As a result, the proposed method can improve the energy efficiency of about 10% compared to the legacy base station.

• Journal of KIISE:Information Networking
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• v.37 no.4
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• pp.294-300
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• 2010

In this paper, We analysis of effective coverage extension for Tri-sector cellular systems using Multi-hop Relay based on IEEE802.16j system. In the proposed international standard of IEEE 802.16j MMR (Mobile Multi-hop Relay) use of the omni-directional antenna, 3-sector and 6-sector antenna is considered to Base Station and Relay Station. Omni-directional antenna service can offer as all directions but a throughput decreases due to the signal interference of near Relay Stations. In the directional antenna, cause of an interference with the base station which it arranges an antenna so that a beam can have the direct and does with neighbor Base Station and Relay Station can be reduced interference, therefore the effective throughput is higher than the omni-directional antenna system. But, In case of Base Station and Relay Station use the directional antenna, the efficiency which the directional antenna has the Co-channel interference due to in the different cell by the channel reuse is decreased. In this study, we propose the structure of arranging the Base Station and Relay Station having the directional antenna in the NBTC, WBTC antenna in a multi-tier. It compared and analyzed with the mode that the multi-hop Relay Station has the omni-directional antenna, Relay Station are used the NBTC antenna and the WBTC antenna system also, We analyze a relation between the performance degradation and the cell coverage extension which it follows because the number of hop in the multi-hop Relay Station.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.87-93
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• 2004

In the design of mobile wireless communication network, BSC(Base Station Location), BSC(Base Station Controller) and MSC(Mobile Switching Center) are the most important parameters. Designing base station location, the cost must be minimized by combining various, complex parameters. We can solve this Problem by combining optimization algorithm, such as Simulated Annealing, Tabu Search, Genetic Algorithm, Random Walk Algorithm that have been used extensively for global optimization. This paper shows the 4 kinds of algorithm to be applied to the optimization of base station location for communication system and then compares, analyzes the results and shows optimization process of algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.525-533
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• 2013

As the number of base stations for mobile communication services rapidly grows with the development of mobile communications and the increase of radio-use devices, there are hazardous concerns raised on the possible health effects of EMF(Electro-magnetic fields) radiated from base station antennas. Since 2007, KCA(Korea Communications Agency) has been measuring the EMF on base station defined by Radio Act. This paper was studied to provide objective and accurate information that relieved anxiety of people by analyzing the measurement results on EMF strength. Also, we suggest to effectiveness and improvement of EMF measurement institution by analyzing measurement results since it was introduced on June 2007.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.179-184
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• 2007

The problem of selecting base station location in the design of mobile communication system has been basically regarded as a problem of assigning maximum users in the cell to the minimum base stations while maintaining minimum SIR. and it is NP hard. The objective function of warehouse location problem, which has been used by many researchers, is not proper function in the base station location problem in CDMA mobile communication, The optimal and approximate solutions have been presented by using proposed object function and algorithms of exact solution, and the simulation results have been assessed and analyzed. The optimal and approximate solutions are found by using mixed integer programming instead of meta-heuristic search methods.