• Title, Summary, Keyword: Portable Internet System

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Analysis of Interference Impacts by UWB System to WiBro Systems

  • Yoon Young-Keun;Jin Rong-Reon;Kim Kyung-Seok;Choi Ik-Guen
    • Journal of electromagnetic engineering and science
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    • v.5 no.4
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    • pp.197-203
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    • 2005
  • This paper evaluates the impacts for interference from UWB system, and determines the tolerable UWB power spectral density(PSD) to the new deploying system, which is called a portable internet service in Korea. It also proposes the interference analysis scheme that can evaluate the characteristics of the performance degradation for portable internet service according to the emission power of UWB systems at the specified frequency bands. The proposed scheme includes a multi-rate and data service environments to deal with interference to portable internet service. It is obtained from simulation results that the transmission PSD of UWB systems should be rigidly restricted by less approximately 10 ${\~}$ 20 dB than FCC provisional limit for coexistence between UWB and portable internet service already allocated at 2.3 GHz frequency bands in Korea.

A Packet Scheduling Algorithm for High-speed Portable Internet System (휴대 인터넷 시스템에서의 패킷 스케줄링 알고리즘 연구)

  • Choi, Seong-Hoon
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.30 no.1
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    • pp.59-65
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    • 2007
  • HPI (High-speed Portable Internet) system which provides high speed internet services is going to be commercialized soon. Since HPI provides simultaneously four different service types such as UGS (Unsolicited Grant Service), rtPS (real time Polling Service), nrtPS(non-real time Polling Service), and BE (Best Effort) under different QoS (Quality of Service) requirements and limited wireless channel resources, efficient packet scheduling mechanisms are necessary to increase the utilization of channels as well as to satisfy the various QoS requirements. This study regards the traffic data to be served as time series and proposes a new packet scheduling algorithm based on the nonparametric statistical test. The performance of the newly proposed algorithm is evaluated through the simulation analysis using a simulator that can evaluate the performance of packet scheduling mechanisms under various values of system parameters and measures such as packet delay time, data transmission rate, number of loss packets, and channel utilization.

Sub-channel Assignments by Link Status on OFDMA Systems for WiBro Service (휴대 인터넷을 위한 OFDMA 시스템에서 무선채널 상태에 따른 서브채널할당)

  • Lim Seog-Ku
    • Proceedings of the Korea Contents Association Conference
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    • pp.596-600
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    • 2005
  • In High-speed Portable Internet system to improve performance of whole system, adaptive modulation and coding technology is used, this technology changes modulation and encoding techniques depending on wireless channel environment. Modulation technology that is used in High-speed Portable Internet system is BPSK, QPSK, 16QAMs and 64QAMs. If terminal is distant from base station transceiver system, BPSK or QPSK technology Is used and 16QAMs or 64QAM technology is used if is near in the base station transceiver system. In this paper, number of sub-channel in each modulation technology minimized total transmitting number of PDU is analyzed for efficient radio resources usage. For this, simulation is conducted and the results are presented at High-speed Portable Internet system environments.

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The study for inter-cell interference reduction techniques in portable internet networks. (휴대인터넷의 셀간 간섭 제거에 관한 연구)

  • Park, Chi-Ho;Hwan, Oh-Young
    • Proceedings of the IEEK Conference
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    • pp.229-230
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    • 2006
  • In this thesis, we analyze performance related to reduction scheme of inter-cell interference causing serious problems in portable internet system. Frequency reusing factor(FUF) is 1 in portable internet system, and it means that a adjacent cell uses same frequency band. This channel environment raises inter-cell interference problem, which provokes serious problems related to system performance and channel capacity. Consequently, it affects deterioration in system performance as a whole. We analyze inter-cell interference when appling a various schemes such as (DCA)Dynamic Channel Allocation, CS(Channel Segregation), IDMA(Interleave Division Multiple Access), FH-OFDM, CRSA(Conceptual Random Subcarrier Allocation), and HDD

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Joint OSIC and Soft ML Decoding Scheme for Coded Layered Space-Time OFDM Systems

  • Lee, Hye-Jeong;Chung, Jae-Ho;Park, Se-Jun;Lee, Seong-Choon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.5A
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    • pp.487-493
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    • 2008
  • In this paper, we consider coded layered space-time architecture in MIMO-OFDM channels. Vertical Bell Lab Layered Space-Time(V-BLAST) scheme employing ordered successive interference cancellation(OSIC) algorithm provides very high spectral efficiency with low computational complexity. However, the error propagation is a major drawback constraining the overall performance of the V-BLAST system significantly. Based on this problem, we derive an improved detector using soft bit log-likelihood ratio(LLR) value. Simulation results show that the proposed detector outperforms the conventional V-BLAST scheme under spatially uncorrelated as well as correlated fading channels.

Performance Analysis of Packet Scheduling Algorithm Based on Delay and Fairness (지연과 공정성을 고려한 패킷 스케쥴링 알고리즘 성능분석)

  • Lim Seog-Ku
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.6 no.6
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    • pp.513-520
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    • 2005
  • High-speed Portable Internet system provides 1-3 Mbps data transmission speed to terminals moving up to 60 km/sec. Since High-speed Portable Internet system supports services requiring different QoS, it needs an efficient scheduling method based on those different QoSs. This paper shows the performance comparisons of several different packet scheduling schemes for minimizing the mean delay over the downlink of High-speed Portable Internet system to support the packet data service. Simulation results show that proposed scheme superior to other schemes at side throughput and data loss rate.

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A Design and Implementation of Efficient Portable Braille Point System for the Visually Impaired Persons (시각 장애인을 위한 효율적인 휴대용 점자시스템의 설계 및 구현)

  • Hwang, Ho-Young;Suh, Hyo-Joong
    • Journal of Internet Computing and Services
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    • v.9 no.5
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    • pp.1-7
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    • 2008
  • This paper explains a new design and Implementation of an efficient portable braille point system for visually Impaired person, The information systems for the visually impaired persons require efficiently designed devices, tools and accessibility to use the devices, and education support. These three conditions are the basic requirements of designing systems for the visually impaired persons, The system proposed in this paper satisfies the above three conditions. The system converts data and web documents between the braille and Hangul using an algorithm stored in a PC, and transfers the converted data to portable devices. And the portable braille device presents the transferred data in an electromagnetic way.

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Development of a Portable Electronic Nose System (I) - System Development - (휴대용 전자코 시스템 개발 (I) - 시스템 개발 -)

  • Lee, Jeong-Woo;Kim, Seong-Min
    • Journal of Biosystems Engineering
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    • v.33 no.5
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    • pp.333-339
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    • 2008
  • The purpose of this study was to develop a portable electronic nose system to measure volatile components of agricultural and food products. Also, a graphical operating software to control the electronic nose system and to acquire signals through the Internet was developed. An array of five commercial metal oxide gas sensors was used to detect various volatile gas components of target samples. Transient and steady state signals were analyzed to extract variables related to sample states, To find optimal operating conditions of the system, several experiments were performed with different gas chambers, vacuum pumps, gas sampling temperatures, and sample container sizes. The patterns of gas sensor signals were analysed to find effects of the various conditions.

Design of TDOA based Wireless Positioning Server Using Portable Internet (휴대인터넷 망을 이용한 TDOA기반 무선 측위서버 구조 설계)

  • Woo, Ho-Shim
    • Journal of KIISE:Information Networking
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    • v.34 no.5
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    • pp.389-395
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    • 2007
  • It is necessary to research on wireless position determination technology that enables location based services on Portable Internet. In this paper, I consider the position determination technology based on TDOA belong to trilateration method. That is using the difference of relative distance between base stations and terminal due to the time difference of arrival of downlink signal. In order to design the positioning server, This paper reviews the related research on current status of wireless position determination technology based on TDOA on Portable Internet. And then, it is suggested that system architecture, network interface, the calculation model for position determination, which are adapted to circumstance of portable Internet. Through this research on the positioning server, it is expected to guarantee that low cost and high efficiency of wireless positioning server on Portable Internet will be developed.

Study of Radio Resource Allocation Method for Wireless Broadband Internet System (휴대인터넷 무선자원 할당 연구)

  • Kook Kwang-Ho;Kim Kyung-Hee;Baek Jang-Hyun
    • Journal of the Korean Operations Research and Management Science Society
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    • v.31 no.3
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    • pp.145-154
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    • 2006
  • WiBro (Wireless Broadband Internet) system is going to be 9ot down to commercialization. The high portable internet system is able to be connected to the high-speed internet using 2.3 GHz frequency bandwidth, anytime and anywhere. An effective scheduling for UGS, rtPS, nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that are the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities with each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.