• 제목/요약/키워드: Mobile Stations

검색결과 436건 처리시간 0.026초

QoS Packet-Scheduling Scheme for VoIP Services in IEEE 802.16e Systems

  • Jang, Jae-Shin;Lee, Jong-Hyup;Cheong, Seung-Kook;Kim, Young-Sun
    • Journal of Communications and Networks
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    • 제11권1호
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    • pp.36-41
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    • 2009
  • The IEEE 802.16 wireless metropolitan area network (WMAN) standard is designed to correct expensive communication costs in CDMA-based mobile communication systems and limited coverage problems in wireless LAN systems. Thus, the IEEE 802.16e standard can provide mobile high-speed packet access between mobile stations and the Internet service provider through the base station with cheap communication fees. To efficiently accommodate voice over IP (VoIP) services in IEEE 802.16 systems, an uplink quality of service packet-scheduling scheme is proposed, and its performance is evaluated with an NS-2 network simulator in this paper. Numerical results show that this proposed scheme can increase the system capacity by 100% more than in the unsolicited rand service (UGS) scheme and 30% more than the extended real-time polling service (ertPS) scheme, respectively.

모바일 환경센서 모듈을 이용한 지하철 2호선의 공기질 분석 (Air Quality Analysis of Subway Station Line Number 2 Using Mobile Environmental Sensor Modules)

  • 나형욱;김창훈;김규식;김희식;김조천
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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    • pp.354-356
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    • 2009
  • Air quality analysis is done for subway trains and subway platforms of subway line number 2 using mobile environmental sensor modules. $CO_2$ and PM10/PM2.5 particulate concentration are investigated for screen door systems, under-ground platforms, and transfer stations. These results would help to increase the quality of life of subway railroad passengers.

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Optimal Base Station Clustering for a Mobile Communication Network Design

  • Hong, Jung-Man;Lee, Jong-Hyup;Lee, Soong-Hee
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제5권5호
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    • pp.1069-1084
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    • 2011
  • This paper considers an optimal base station clustering problem for designing a mobile (wireless) communication network. For a given network with a set of nodes (base stations), the problem is to optimally partition the set of nodes into subsets (each called a cluster) such that the associated inter-cluster traffic is minimized under certain topological constraints and cluster capacity constraints. In the problem analysis, the problem is formulated as an integer programming problem. The integer programming problem is then transformed into a binary integer programming problem, for which the associated linear programming relaxation is solved in a column generation approach assisted by a branch-and-bound procedure. For the column generation, both a heuristic algorithm and a valid inequality approach are exploited. Various numerical examples are solved to evaluate the effectiveness of the LP (Linear Programming) based branch-and-bound algorithm.

MMR(Mobile Multihop Relay) 시스템의 용량 분석 (Capacity Analysis of MMR(Mobile Multihop Relay) System)

  • 이강원;국광호;최송인
    • 산업공학
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    • 제21권2호
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    • pp.189-197
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    • 2008
  • This study shows achievable capacity gain from the MMR system. Relay stations are placed along the cell boundary in tiers. We can have as many tiers of relays and as many relays in each tier as we want. A model is developed, which can estimate the system capacity varying the number of relays in each tier and the bandwidths allocated to the BS and the RS. It is shown that maximum capacity increases are 21.5% and 18.9% when we have relays in the first tier only and in the first and the second tiers, respectively.

A Bandwidth Adaptive Path Selection Scheme in IEEE 802.16 Relay Networks

  • Lee, Sung-Hee;Ko, Young-Bae
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제5권3호
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    • pp.477-493
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    • 2011
  • The IEEE 802.16 mobile multi-hop relay (MMR) task group 'j' (TGj) has introduced the multi-hop relaying concept in the IEEE 802.16 Wireless MAN, wherein a relay station (RS) is employed to improve network coverage and capacity. Several RSs can be deployed between a base station and mobile stations, and configured to form a tree-like multi-hop topology. In such architecture, we consider the problem of a path selection through which the mobile station in and outside the coverage can communicate with the base station. In this paper, we propose a new path selection algorithm that ensures more efficient distribution of resources such as bandwidth among the relaying nodes for improving the overall performance of the network. Performance of our proposed scheme is compared with the path selection algorithms based on loss rate and the shortest path algorithm. Based on the simulation results using ns-2, we show our proposal significantly improves the performance on throughput, latency and bandwidth consumption.

A Proposal of the Authentication Protocol for Wireless Mobile Communication Systems Using Keyed Hash Function

  • Park, Young-Ho
    • 한국산업정보학회논문지
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    • 제6권1호
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    • pp.56-60
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    • 2001
  • 본 논문에서는 무선이동 통신시스템을 위한 인증 프로토콜을 제안한다. 제안한 프로토콜은 상호 인증과 세션 키 분배를 제공하기 위해서 키 해쉬 함수를 사용한다. 본 프로토콜은 이 동국에서의 계산량이 적다. 또한, 중간 전송 네트워크에서의 최소 보호설정을 제공하기 위하여 고정 망에서의 보호 설정을 하지 않았다.

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이동통신망에서 영역기준 위치등록과 2단계 페이징의 최적화

  • 김경희;유병한;백장현
    • 한국경영과학회:학술대회논문집
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    • 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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    • pp.128-135
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    • 2002
  • An efficient mobility management for mobile stations plays an important role in mobile communication network. This paper studios a zone-based registration (ZBR) that is implemented in most of mobile communication systems. We introduce the mobility management scheme that combines a zone-based registration and a selective paging (SP) and analyze its performance. We set up an analytical model based on 2-dimensional random walk mobility model and evaluate the performance of the proposed mobility management scheme using the model to determine the optimal size of location area which will result in the minimum signaling traffic on radio channels. Numerical results are provided to demonstrate the performance of the proposed mobility management scheme under various circumstances.

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개인 이동 통신 상에서 가상 계층을 이용한 위치 갱신 트래픽의 감소 (Reduction of Location Update Traffic Using Virtual Layer in PCS)

  • 정대우;추현승;윤희용;박경린
    • 한국시뮬레이션학회논문지
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    • 제10권2호
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    • pp.47-60
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    • 2001
  • In mobile wireless network efficient location management for tracking and finding mobile users is a critical issue. The traffic for location update can be excessive, especially at the base stations that are near to the location area (LA) boundaries. In this paper we propose a new location update scheme which can significantly reduce the signaling traffic for location update. It is based on the virtual layer approach employing SubMSCs. The virtual layer is laid upon the original layer of LAs such that the mobile terminals moving around the boundary cells of adjacent LAs become to move within a virtual LA. As a result, the location update traffic is substantially reduced compared to overlapping scheme which is the most recent and efficient location update scheme.

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휴대폰용 전력증폭기의 신뢰성 평가기준 (Reliability Assessment Criteria of Power Amplifier for Mobile Phone)

  • 이우성;황순미;이관훈;송병석;정해성;오근태
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제9권3호
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    • pp.233-248
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    • 2009
  • PAM(Power Amplifier Module) is the important part of a mobile phone transmitter. It amplifies the strength of signal transmitting from a mobile phone to base stations enough to resist noise or interference. In this paper reliability assessment criteria for the PAM are established in terms of quality certification test and lifetime test. The former quality certification test comprises general performance test and environmental test. Items which pass the test undergo lifetime test which guarantees the extent of mean lifetime with certain confidence.

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Calculation Of Mobile Location Based On TOA/SS Measurements

  • Huang, Jiyan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제6권12호
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    • pp.3166-3181
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    • 2012
  • Localization of mobile station (MS) has now gained considerable attention. Since the hybrid measurements can help to improve the positioning accuracy, several hybrid localization methods have been proposed in the literature. However, the high performance estimator with the closed-form solution and complete performance analysis for time-of-arrival/signal strength (TOA/SS) localization technique is still an opening issue. Two TOA/SS localization algorithms with the closed-form solutions are proposed for the cases with or without uncertainty in the positions of base stations. Furthermore, performance analysis for the TOA/SS localization technique is presented. Both the theoretical variances and Cramer-Rao lower bounds (CRLBs) are derived and the relationship between the cases with or without uncertainty is given. The paper also proves that the TOA/SS scheme has a lower CRLB than the TOA (or SS) scheme. Theoretical analysis and simulations show that the proposed method can reach its CRLB.