• Title/Summary/Keyword: WiFi(Wireless)

Search Result 360, Processing Time 0.026 seconds

Design and Implementation of Adaptive Beam-forming System for Wi-Fi Systems (무선랜 시스템을 위한 적응형 빔포밍 시스템의 설계 및 구현)

  • Oh, Joohyeon;Gwag, Gyounghun;Oh, Youngseok;Cho, Sungmin;Oh, Hyukjun
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.18 no.9
    • /
    • pp.2109-2116
    • /
    • 2014
  • This paper presents the implementation and design of the advanced WI-FI systems with beam-forming antenna that radiate their power to the direction of user equipment to improve the overall throughput, contrast to the general WI-FI systems equipped with omni-antenna. The system consists of patch array antenna, DSP, FPGA, and Qualcomm's commercial chip. The beam-forming system on the FPGA utilizes the packet information from Qualcomm's commercial chip to control the phase shifters and attenuators of the patch array antenna. The PCI express interface has been used to maximize the communication speed between DSP and FPGA. The directions of arrival of users are managed using the database, and each user is distinguished by the MAC address given from the packet information. When the system wants to transmit a packet to one user, it forms beams to the direction of arrival of the corresponding user stored in the database to maximize the throughput. Directions of arrival of users are estimated using the received preamble in the packet to make its SINR as high as possible. The proposed beam-forming system was implemented using an FPGA and Qualcommm's commercial chip together. The implemented system showed considerable throughput improvement over the existing general AP system with omni-directional antenna in the multi-user communication environment.

IoT-based Smart Tunnel Accident Alert System (사물 인터넷 기반의 스마트 터널 사고 경보 시스템)

  • Ki-Ung Min;Seong-Noh Lee;Yoon-Hwa Choi;Yeon-Taek Hong;Chul-Sun Lee;Yun-Seok Ko
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.19 no.4
    • /
    • pp.753-762
    • /
    • 2024
  • Tunnels have limited evacuation areas, and It is difficult for cars coming from behind to recognize the accident situation in front. Since an accident is very likely to lead to a serious secondary accident, a IoT-based smart tunnel accident warning system was studied to prepare for traffic accidents that occur in tunnels. If the measured values from the flame detection sensor, gas detection sensor, and shock detection sensor in the tunnel exceed the standard, it is judged to be an emergency situation and an alert system is designed to operate. The accident information message was designed to be displayed on the LCD and transmitted to drivers inside and outside the tunnel through a Wi-Fi communication network. A performance test system was established and performance evaluation was performed for several accident scenarios. As a result of the test, it was confirmed that the accident alert system can accurately detect accidents based on given reference values, perform alert procedures, and transmit alert messages to smart phones through Wi-Fi wireless communication. And through this, its effectiveness could be confirmed.

The Individual Discrimination Location Tracking Technology for Multimodal Interaction at the Exhibition (전시 공간에서 다중 인터랙션을 위한 개인식별 위치 측위 기술 연구)

  • Jung, Hyun-Chul;Kim, Nam-Jin;Choi, Lee-Kwon
    • Journal of Intelligence and Information Systems
    • /
    • v.18 no.2
    • /
    • pp.19-28
    • /
    • 2012
  • After the internet era, we are moving to the ubiquitous society. Nowadays the people are interested in the multimodal interaction technology, which enables audience to naturally interact with the computing environment at the exhibitions such as gallery, museum, and park. Also, there are other attempts to provide additional service based on the location information of the audience, or to improve and deploy interaction between subjects and audience by analyzing the using pattern of the people. In order to provide multimodal interaction service to the audience at the exhibition, it is important to distinguish the individuals and trace their location and route. For the location tracking on the outside, GPS is widely used nowadays. GPS is able to get the real time location of the subjects moving fast, so this is one of the important technologies in the field requiring location tracking service. However, as GPS uses the location tracking method using satellites, the service cannot be used on the inside, because it cannot catch the satellite signal. For this reason, the studies about inside location tracking are going on using very short range communication service such as ZigBee, UWB, RFID, as well as using mobile communication network and wireless lan service. However these technologies have shortcomings in that the audience needs to use additional sensor device and it becomes difficult and expensive as the density of the target area gets higher. In addition, the usual exhibition environment has many obstacles for the network, which makes the performance of the system to fall. Above all these things, the biggest problem is that the interaction method using the devices based on the old technologies cannot provide natural service to the users. Plus the system uses sensor recognition method, so multiple users should equip the devices. Therefore, there is the limitation in the number of the users that can use the system simultaneously. In order to make up for these shortcomings, in this study we suggest a technology that gets the exact location information of the users through the location mapping technology using Wi-Fi and 3d camera of the smartphones. We applied the signal amplitude of access point using wireless lan, to develop inside location tracking system with lower price. AP is cheaper than other devices used in other tracking techniques, and by installing the software to the user's mobile device it can be directly used as the tracking system device. We used the Microsoft Kinect sensor for the 3D Camera. Kinect is equippedwith the function discriminating the depth and human information inside the shooting area. Therefore it is appropriate to extract user's body, vector, and acceleration information with low price. We confirm the location of the audience using the cell ID obtained from the Wi-Fi signal. By using smartphones as the basic device for the location service, we solve the problems of additional tagging device and provide environment that multiple users can get the interaction service simultaneously. 3d cameras located at each cell areas get the exact location and status information of the users. The 3d cameras are connected to the Camera Client, calculate the mapping information aligned to each cells, get the exact information of the users, and get the status and pattern information of the audience. The location mapping technique of Camera Client decreases the error rate that occurs on the inside location service, increases accuracy of individual discrimination in the area through the individual discrimination based on body information, and establishes the foundation of the multimodal interaction technology at the exhibition. Calculated data and information enables the users to get the appropriate interaction service through the main server.

Compact and Flexible Monopole Antenna for Ultra-Wideband Applications Deploying Fractal Geometry

  • Geetha, G;Palaniswamy, Sandeep Kumar;Alsath, M. Gulam Nabi;Kanagasabai, Malathi;Rao, T. Rama
    • Journal of Electrical Engineering and Technology
    • /
    • v.13 no.1
    • /
    • pp.400-405
    • /
    • 2018
  • This paper presents a compact ultra-wideband (UWB) flexible monopole antenna design on a paper substrate. The proposed antenna is made of iterations of a circular slot inside an octagonal metallic patch. This fractal-based geometry has been deployed to achieve compactness along with improved bandwidth, measured reflection coefficient -10 dB bandwidth ranging from 2.7 to 15.8 GHz. The overall size of the antenna is $26mm{\times}19mm{\times}0.5mm$, which makes it a compact one. The substrate used is paper and the main features like environment friendly, flexibility, green electronics applications and low cost of fabrication are the key factors for the proposed antenna. The aforementioned UWB prototype is suitable for many wireless communication systems such as WiMAX, WiFi, RFID and WSN applications. Antenna has been tested for the effect of bending by placing it over a curved surface of a very small radius of 10 mm.

Radio Frequency Based Emergency Exit Node Technology

  • Choi, Youngwoo;Kim, Dong Kyoo;Kang, Do Wook;Choi, Wan Sik
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.2 no.1
    • /
    • pp.91-100
    • /
    • 2013
  • This paper introduces an indoor sensor fusion wireless communication device which provides the Location Based Service (LBS) using fire prevention facility. The proposed system can provide information in real time by optimizing the hardware of Wi-Fi technology. The proposed system can be applied to a fire prevention facility (i.e., emergency exit) and provide information such as escape way, emergency exit location, and accident alarm to smart phone users, dedicated terminal holders, or other related organizations including guardians, which makes them respond instantly with lifesaving, emergency mobilization, etc. Also, the proposed system can be used as a composite fire detection sensor node with additional fire and motion detect sensors.

Hybrid Communication Network Architectures for Monitoring Large-Scale Wind Turbine

  • Ahmed, Mohamed A.;Kim, Young-Chon
    • Journal of Electrical Engineering and Technology
    • /
    • v.8 no.6
    • /
    • pp.1626-1636
    • /
    • 2013
  • Nowadays, a rapid development in wind power technologies is occurring compared with other renewable energies. This advance in technology has facilitated a new generation of wind turbines with larger capacity and higher efficiency. As the height of the turbines and the distance between turbines increases, the monitoring and control of this new generation wind turbines presents new challenges. This paper presents the architectural design, simulation, and evaluation of hybrid communication networks for a large-scale wind turbine (WT). The communication network of WT is designed based on logical node (LN) concepts of the IEC 61400-25 standard. The proposed hybrid network architectures are modeled and evaluated by OPNET. We also investigate network performance using three different technologies: Ethernet-based, WiFi-based, and ZigBee-based. Our network model is validated by analyzing the simulation results. This work contributes to the design of a reliable communication network for monitoring and controlling a wind power farms (WPF).

A Trend to Next-Generation Wireless LAN and Standardization Activity in IEEE 802.11 (차세대무선랜 기술 및 표준화 동향)

  • Lee, Je-Heon;Lee, Seok-Gyu
    • Electronics and Telecommunications Trends
    • /
    • v.23 no.3
    • /
    • pp.19-28
    • /
    • 2008
  • 2007년 3월부터 WFA에서 시작된 "Wi-Fi CERTIFIED(TM)802.11n Draft 2.0" 인증을 통해 현재까지 180가지가 넘는 제품이 출시되고 있는 가운데 이러한 시장의 상황을 반영하듯 여러 매체를 통해 IEEE 802.11n이 2008년 핫이슈로 등장하고 있다. 하지만 차세대무선통신의 기술적인 로드맵을 선도하고 있는 ITU-R WP8F의 IMT-Advanced에서 요구하고 있는 보행시 1Gbps까지 가능하게 하는 기술을 2010년까지 제공한다는 측면에서는 IEEE 802.11n의 성능이 못 미치는 게 사실이며, 이러한 상황을 반영해 IEEE 802.11 내부에서 IEEE 802.11n 후속으로 보행시 Gbps급의 전송 속도를 지원하는 새로운 기술에 대한 표준화 작업에 대한 논의가 꾸준히 있어 왔고, 그 결과 2007년 5월 정식으로 이를 위한 Study Group이 만들어져 작업에 들어갔다. 본 고에서는 이러한 IEEE 802.11에서의 표준화 활동을 중심으로 차세대무선랜에 대한 응용분야, 관련 기술, 표준화 작업 내용에 대해 살펴보고자 한다.

Multi transmission method of data among near smart devices using inaudible sound and wireless network

  • Chung, Myoungbeom
    • Journal of the Korea Society of Computer and Information
    • /
    • v.20 no.12
    • /
    • pp.83-90
    • /
    • 2015
  • In this paper, we propose a new method for multi transmission method of data among near smart devices. Existing methods require the use of an extra application service where the operating system differs between smart devices. In contrast, the proposed method makes use of the smart device's inner speaker and microphone to confirm the transmission signal. Then, real sharing data is transmitted via WiFi or LTE. Therefore, the proposed method overcomes operating system issues with existing methods. Besides, BUMP technology works in a similar way to the method we propose, it only supports one-to-one transmission. To evaluate the efficacy of the new method, we tested one-to-many data transmission in an experiment: the results showed a 96% success rate. As a result, we believe that the proposed method is an effective multi transmission method of data among near smart devices.

Design and Implementation of Emergency Calamity System within Wireless Personal Area Network (근거리 무선 통신을 이용한 긴급재난상황 설계 및 구현)

  • Kim, Young-Ji;Lim, Choong-Soo
    • Proceedings of the Korean Society of Computer Information Conference
    • /
    • 2008.06a
    • /
    • pp.269-273
    • /
    • 2008
  • 본 논문에서는 근거리 무선 통신을 이용하여 사용자의 현재 위치에서 일어나고 있는 교통사고, 화재, 환자발생 등의 긴급재난상황 목격시 사용자가 해당 상황을 ZigBee 기반의 무선 센서 네트워크 사용자에게 알리고, 알린 정보를 실시간 쉽게 확인 할 수 있도록 긴급재난상황을 모니터링 하는 시스템을 제안하였다. 근거리 무선 통신 중센서와 사용자 무선 단말기 사이의 데이터 전송 구조가 간단하고, 초저가의 센서 네트워크 구성시 낮은 전력을 소모하는 장점을 가진 ZigBee로 구현하였다. 현재 사용자 주변의 일어나는 긴급재난 상황을 주변 사용자와 ZigBee 기반의 무선 센서 네트워크를 구축하여 실시간으로 보다 정확한 정보를 주변 사용자에게 알려주거나 혹은 사용자가 모니터링을 하여 사용자의 피해를 최소화로 줄여 사용자의 안전과 편의를 향상시킨다.

  • PDF

The Implementation of Wireless Fine Dust Sensor System Based on Arduino (아두이노 기반의 미세먼지정보 무선전송 시스템 구현)

  • Kim, Jin-Gyeong;Ra, Sang-Yong;Kim, Min-Seok;Kim, Jung-Hoon;Lee, Jun-Dong
    • Proceedings of the Korean Society of Computer Information Conference
    • /
    • 2018.07a
    • /
    • pp.234-235
    • /
    • 2018
  • 본 논문에서는 R.Box와 연결되어 미세먼지정보를 무선으로 전송하는 아두이노 기반의 시스템을 제안한다. R.Box는 라즈베리파이를 기반으로 다양한 센서로 구성된 일반목적의 IoT 허브이다. 아두이노와 미세먼지센서를 이용해 미세먼지농도를 측정하고 데이터를 WiFi를 통해 R.Box로 전송한다. 아두이노와 R.Box는 TCP 소켓 방식으로 통신하며 이 시스템을 통하여 원하는 위치의 미세먼지정보를 확인할 수 있다.

  • PDF