• Title, Summary, Keyword: wireless local area network(WLAN)

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The Frequency Adaptive antenna Matching Network Design for Improving Wireless LAN Performance (무선랜 송수신 특성 개선을 위한 주파수 적응형 안테나 정합 회로 구조 설계)

  • Park, Kyoung-Jin;Ra, Keuk-Hwan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.4
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    • pp.41-46
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    • 2012
  • This paper suggested that the frequency adaptive antenna matching network design between AP and WLAN(Wireless Local Area Network) terminal for improving performance. The internet data service of the WLAN terminal is communicated through the AP and AP broadcasts the beacon signal including the assigned frequency channel. at that time the antenna matching network path is controlled beacon information after the WLAN terminal searching and synchronization a beacon information. and then the WLAN terminal communicate with AP. controlling the antenna matching network path according to channel information, The WLAN terminal is expected to improve RF output power and sensitivity performance. The VSWR(Voltage Standing Wave Ratio) performance of the designed antenna matching network is measured to about 1.1 ~ 1.2 and then it is operated by the channel information of the AP.

A Novel Idle Mode Operation in IEEE 802.11 WLANs: Prototype Implementation and Performance Evaluation (IEEE 802.11 WLAN을 위한 Idle Mode Operation: Prototype 구현 및 성능 측정)

  • Jin, Sung-Geun;Han, Kwang-Hun;Choi, Sung-Hyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.2A
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    • pp.152-161
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    • 2007
  • IEEE 802.11 Wireless Local Area Network (WLAN) became a prevailing technology for the broadband wireless Internet access, and new applications such as Voice over WLAM (VoWLAN) are fast emerging today. For the battery-powered VoWLAN devices, the standby time extension is a key concern for the market acceptance while today's 802.11 is not optimized for such an operation. In this paper, we propose a novel Idle Mode operation, which comprises paging, idle handoff, and delayed handoff. Under the idle mode operation, a Mobile Host (MH) does not need to perform a handoff within a predefined Paging Area (PA). Only when the MH enters a new PA, an idle handoff is performed with a minimum level of signaling. Due to the absence of such an idle mode operation, both IP paging and Power Saving Mode (PSM) have been considered the alternatives so far even though they are not efficient approaches. We implement our proposed scheme in order to prove the feasibility. The implemented prototype demonstrates that the proposed scheme outperforms the legacy alternatives with respect to energy consumption, thus extending the standby time.

A Testbed of Performance Evaluation for Fingerprint Based WLAN Positioning System

  • Zhao, Wanlong;Han, Shuai;Meng, Weixiao;Zou, Deyue
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.6
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    • pp.2583-2605
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    • 2016
  • Fingerprint positioning is a main stream and key technique for seamless positioning systems. In this paper, we develop a performance evaluation testbed for fingerprint based Wireless Local Area Network (WLAN) positioning system. The testbed consists of positioning server, positioning terminal, Access Point (AP) units, positioning accuracy analysis system and testing scenarios. Different from other testbeds tended to focus on testing in same situation, in the proposed testbed, a couple of scenarios are set to test the positioning system including indoor and outdoor environments. Handset-side positioning mode and network-side positioning mode are provided simultaneously. Variety of motion models, such as static model, low-speed model and high-speed model are considered as well as different positioning algorithms. Finally, some implementation cases are analyzed to verify the credibility of the testbed.

Variable gain LNA Design for 2.4GHz Wireless LAN (2.4GHz 무선랜용 가변이득 저잡음 증폭기 설계)

  • 강태영;박영호;임지훈;박정호
    • Proceedings of the IEEK Conference
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    • pp.621-624
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    • 2003
  • In this paper, two Cascode Low Noise Variable Gain Amplifiers are proposed for wide dynamic range and constant Noise Figure for frequency range of 2.4GHz. Designed Variable Gain Low Noise Amplifier are for Wireless Local Area Network (WLAN) applications. A gain is higher than 17dB and the noise figure is approximately 1.3dB and the input VSWR is better than 2:1.

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IEEE 802.19 무선 상호공존 표준화 동향

  • Gang, Hyeon-Deok;Park, Ae-Sun;Bang, Seung-Chan
    • Information and Communications Magazine
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    • v.33 no.10
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    • pp.24-30
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    • 2016
  • 본고에서는 IEEE 802.19 무선 상호공존(Wireless Coexistence) 워킹그룹(Working Group)의 구성 및 역할, TV 우휴대역 주파수 공유 시스템간 상호공존 표준기술 및 현재 논의가 진행중인 일반허가접속(General Authorized Access) 주파수 공유시스템간 상호공존 표준기술과 자동차 환경에서의 주파수 공유시스템간 상호공존 표준기술을 소개하고, 비면허대역 LTE(Long Term Evolution)와 무선랜(Wireless Local Area Network, WLAN) 시스템과의 주파수 공유 등의 무선상호공존 이슈들과 관련 표준화 동향에 대해 알아본다.

X-band CMOS VCO for 5 GHz Wireless LAN

  • kim, Insik;Ryu, Seonghan
    • International journal of advanced smart convergence
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    • v.9 no.1
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    • pp.172-176
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    • 2020
  • The implementation of a low phase noise voltage controlled oscillator (VCO) is important for the signal integrity of wireless communication terminal. A low phase noise wideband VCO for a wireless local area network (WLAN) application is presented in this paper. A 6-bit coarse tune capacitor bank (capbank) and a fine tune varactor are used in the VCO to cover the target band. The simulated oscillation frequency tuning range is from 8.6 to 11.6 GHz. The proposed VCO is desgned using 65 nm CMOS technology with a high quality (Q) factor bondwire inductor. The VCO is biased with 1.8 V VDD and shows 9.7 mA current consumption. The VCO exhibits a phase noise of -122.77 and -111.14 dBc/Hz at 1 MHz offset from 8.6 and 11.6 GHz carrier frequency, respectively. The calculated figure of merit(FOM) is -189 dBC/Hz at 1 MHz offset from 8.6 GHz carrier. The simulated results show that the proposed VCO performance satisfies the required specification of WLAN standard.

Symbol Time Tracking Algorithm for WAVE Systems (WAVE 시스템에서 심볼 시간추적 알고리듬)

  • Hong, Dae-Ki
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.2
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    • pp.397-406
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    • 2009
  • A Wireless Access for Vehicular Environment (WAVE) system based on Orthogonal frequency Division Multiplexing (OFDM) is made for vehicle to vehicle wireless communications. The physical layer standard of the WAVE system is very similar to that of the IEEE802.1la wireless local area network (WLAN). Therefore, the performance of the WAVE system is degraded by continual timing delay in the WAVE multipath fading channels after starting initial timing synchronization. In this paper, the tracking algorithm that synchronizes symbol timing is proposed to continually compensate additional timing delay. Computer simulation of the proposed algorithm is performed in the worst communication environments that apply to maximum timing delay. Computer simulation shows that the proposed algorithm can improve the system performance in various channel conditions.

A Study of an Association Admission Method for Public Wireless LAN Systems (고속 공중 무선랜 시스템을 위한 효율적인 연결 수락 제어방법의 연구)

  • Lee, Hyun-Woo;Yoon, Hong;Yoon, Chong-Ho
    • The Journal of Advanced Navigation Technology
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    • v.7 no.2
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    • pp.149-155
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    • 2003
  • This paper generally relates to the field of wireless local area networks(WLANs), and more particularly, to AP selection and association methods for the performance of a station. In these days, IEEE 802.11 Wireless LAN network is widely deployed and used as an emerging service to connect high-speed Internet in the public wireless environment. But, if there are many users in hot spot area, they suffer a severe decrease of performance. Thus it needs an association and access control mechanism especially when it is used in the public environment. In this paper, we suggest a selection and association method using Beacon or Probe Response frames based IEEE 802.11. Station selects AP using the information of the capacity area in a Beacon or a Probe Response frame. According to the present paper, an association method for a public WLAN service, which includes a WLAN user terminal and an AP for relaying WLAN communications to and from the user terminal, includes the steps of the user terminal asking the AP's states for access to a radio channel; and the station selects and associates with the AP. According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

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Performance of Multi-User MIMO/OFDM System using Cyclic Delay Diversity for Fading Channels (페이딩 채널에서 순환 지연 다이버시티를 적용한 다중 사용자 MIMO OFDM 시스템의 성능)

  • Park, In-Hwan;Kim, Yoon-Hyun;Kim, Jin-Young
    • The Journal of The Institute of Internet, Broadcasting and Communication
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    • v.10 no.6
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    • pp.263-268
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    • 2010
  • As the demand of high quality service in next generation wireless communication systems, a high performance of data transmission requires an increase of spectrum efficiency and an improvement of error performance in wireless communication systems. In this paper, we propose a multi-user multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with cyclic delay diversity and block diagonalization procoding method to improve bit error rate (BER) performance with wireless local area network (WLAN) channel model C and D for 802.11n WLAN system. The results of mathlab simulation show the improvement of BER performance in 802.11n wireless indoor channel environment.

Development of Malicious Traffic Detection and Prevention System by Embedded Module on Wireless LAN Access Point (무선 LAN Access Point에서 임베디드 형태의 유해 트래픽 침입탐지/차단 시스템 개발)

  • Lee, Hyung-Woo;Choi, Chang-Won
    • The Journal of the Korea Contents Association
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    • v.6 no.12
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    • pp.29-39
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    • 2006
  • With the increasing popularity of the wireless network, the vulnerability issue on IEEE 802.1x Wireless Local Area Network (WLAN) are more serious than we expected. Security issues range from mis-configured wireless Access Point(AP) such as session hijacking to Denial of Service(DoS) attack. We propose a new system based on intrusion detection or prevention mechanism to protect the wireless network against these attacks. The proposed system has a security solution on AP that includes an intrusion detection and protection system(IDS/IPS) as an embedded module. In this paper, we suggest integrated wireless IDS/IPS module on AP with wireless traffic monitoring, analysis and packet filtering module against malicious wireless attacks. We also present that the system provides both enhanced security and performance such as on the university wireless campus network.

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