• Title/Summary/Keyword: short-range wireless access

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A Primary Channel Selection Scheme for Wideband WLAN V2X Communication (무선랜 기반 광대역 V2X 통신에서의 채널 접근 동작을 위한 주 채널 설정 기법)

  • Hong, Hanseul;Kim, Ronny Yongho;Ahn, Woojin
    • Journal of Advanced Navigation Technology
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    • v.23 no.6
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    • pp.589-596
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    • 2019
  • With the proliferation of intelligent transportation system (ITS) with dedicated short-range communication (DSRC) deployment, there are various applications requiring different throughput and reliability performance. To meet the enhanced throughput requirements in newly generated applications, IEEE 802.11bd is proposed to standardize for support of enhanced throughput and latency, preserving the fairness with previously deployed WLAN V2X devices. One of the main features of IEEE 802.11 bd is 20 MHz transmission to support the high data rate. In this paper, the primary channel selection method is proposed to guarantee the fairness with frame transmissions with 10 MHz bandwith including communications in WLAN V2X devices deployed with IEEE 802.11p. Simulation shows that the proposed channel access method for 20 MHz transmission with primary selection preserves the fairness without the change of channel access method in wide-band transmission.

Design of a bluetooth-based interactive control network

  • Kwak, Jae-Hyuk;Lim, Joon-Hong
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.922-925
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    • 2004
  • Bluetooth technology is essentially a method for wireless connection of a diverse set of devices ranging from PDAs, mobile phone, notebook computers, to another equipments. The bluetooth system supports both point-to-point connection and point-to-multipoint connections. In point-to-multipoint connection, the channel is shared among several bluetooth devices. Two or more devices sharing the same channel form a piconet. There is one master device and up to seven active slave devices in a piconet. The radio operates in the unlicensed 2.45GHz ISM band. This allows users who travel world-wide to use bluetooth equipments anywhere. Since the link is based on frequency-hop spread spectrum, multiple channels can exist at the same time. The Bluetooth standard has been suggested that Bluetooth equipments can be used in the short-range, maximum 100 meters . It has been defined that the time takes to setup and establish a bluetooth connection among devices is 10 seconds. It is a long time and may be a cause to lose a chance of finding other non-fixed devices. We propose a routing protocols for scatternets which can be used to control a mobile units(MUs) in this network. The proposed routing protocol is composed of two kinds of bluetooth information, access point(AP) and MU.

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An Automatic Access Registration System using Beacon and Deep Learning Technology (비콘과 딥러닝 기술을 활용한 전자출입명부 자동등록시스템)

  • Huh, Ji-Won;Ohm, Seong-Yong
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.4
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    • pp.807-812
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    • 2020
  • In order to prevent the national wide spread of the COVID-19 virus, the government enforces to use an electronic access registration system for public facilities to effectively track and manage the spread. Initially, there was a lot of hassle to write a directory, but recently a system for creating an electronic access list using QR codes, what is called KI-Pass, is mainly used. However, the procedure for generating a QR code is somewhat cumbersome. In this paper, we propose a new electronic access registration system that does not require QR code. This system effectively controls the suspicious visitor by using a mask wearing discriminator which has been implemented using deep learning technology, and a non-contact thermometer package. In addition, by linking the beacon, a short-range wireless communication technology, and the visitor's smartphone application, basic information of the facility visitor is automatically registered to KDCA through the server. On the other hand, the user access information registered in the server is encrypted and stored, and is automatically destroyed after up to 4 weeks. This system is expected to be very effective in preventing the spread of other new infectious diseases as well as responding to the coronavirus which is recording a high spread worldwide.

Implemention of Refrigerator Application using NFC (NFC를 이용한 냉장고 Application 구현)

  • Ham, Ji-Hun;Yun, Min-Gyu;Han, Jung-Woo;Kim, Tae Yong;Jang, Won-Tae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.570-572
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    • 2015
  • NFC (Near Field Communication) is an area of the RFID technology is a kind of short-range wireless communication. NFC technology is to utilize the data transfer, the access control system is usefully employed in many fields, such as mobile payment. Recently smartphone application development using NFC is activated, recognition of the convenience of the current NFC tag is insignificant state. In this paper, it is the content of the Application that was created in order to provide the knowledge of convenience food to the customer to visit the mart. Users with Mart, using smartphones, at a NFC tag that is attached to the food display stand food information, purchasing tips, keeping method, data such efficacy is provided over the screen of the smartphone. If you purchased the food is placed in the refrigerator "moves to the food list of application to click the button, through the food list screen their food list in the refrigerator, and by providing information such as expiration date, the user There is help me to be able to buy the more convenient food.

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Power-Efficient Broadcasting Scheme for Mobile VOD System (모바일 VOD 시스템의 전력효율을 감안한 브로드캐스팅 기법)

  • Choi, Young;Choi, Hwang-Kyu
    • Journal of Korea Multimedia Society
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    • v.10 no.5
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    • pp.612-622
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    • 2007
  • As compared with wired network environment, mobile VOD service in wireless network environment is difficult to guarantee the quality of VOD service due to the limitation of the system resources. Moreover, the wireless network has small bandwidth resources and short access range so that has limitations for providing the service to a large number of mobile clients. The limited battery capacity of a mobile device becomes an obstacle to mobile clients for enjoying VOD service for a long time. Therefore, these drawbacks should be considered in developing mobile VOD applications. This paper proposes a new technique for improving QoS of mobile VOD service by jointly use of broadcasting technique, which can provide VOD service to a large number of mobile clients simultaneously, and bursty communication technique, which can reduce the power consumption of a mobile device. With having these two techniques, streaming data are divided into segments, each of which is grouped into a particular packet and then transmitted at a time in the busty communication manner. In the performance evaluation, the power consumption on WNIC of a mobile device can be reduced by over 80%, and the initial service delay can be reduced in proportion to the number of channels compared with the existing staggered broadcasting technique.

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Hardware Design for Timing Synchronization of OFDM-Based WAVE Systems (OFDM 기반 WAVE 시스템의 시간동기 하드웨어 설계)

  • Huynh, Tronganh;Kim, Jin-Sang;Cho, Won-Kyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.4A
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    • pp.473-478
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    • 2008
  • WAVE is a short-to-medium range communication standard that supports both public safety and private operations in roadside-to-vehicle and vehicle-to-vehicle communication environments. The core technology of physical layer in WAVE is orthogonal frequency division multiplexing (OFDM), which is sensitive to timing synchronization error. Besides, minimizing the latency in communication link is an essential characteristic of WAVE system. In this paper, a robust, low-complexity and small-latency timing synchronization algorithm suitable for WAVE system and its efficient hardware architecture are proposed. The comparison between proposed algorithm and other algorithms in terms of computational complexity and latency has shown the advantage of the proposed algorithm. The proposed architecture does not require RAM (Random Access Memory) which can affect the pipe lining ability and high speed operation of the hardware implementation. Synchronization error rate (SER) evaluation using both Matlab and FPGA implementation shows that the proposed algorithm exhibits a good performance over the existing algorithms.

Design and Implementation of a Bluetooth Baseband Module with DMA Interface (DMA 인터페이스를 갖는 블루투스 기저대역 모듈의 설계 및 구현)

  • Cheon, Ik-Jae;O, Jong-Hwan;Im, Ji-Suk;Kim, Bo-Gwan;Park, In-Cheol
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.39 no.3
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    • pp.98-109
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    • 2002
  • Bluetooth technology is a publicly available specification proposed for Radio Frequency (RF) communication for short-range :1nd point-to-multipoint voice and data transfer. It operates in the 2.4㎓ ISM(Industrial, Scientific and Medical) band and offers the potential for low-cost, broadband wireless access for various mobile and portable devices at range of about 10 meters. In this paper, we describe the structure and the test results of the bluetooth baseband module with direct memory access method we have developed. This module consists of three blocks; link controller, UART interface, and audio CODEC. This module has a bus interface for data communication between this module and main processor and a RF interface for the transmission of bit-stream between this module and RF module. The bus interface includes DMA interface. Compared with the link controller with FIFOs, The module with DMA has a wide difference in size of module and speed of data processing. The small size module supplies lorr cost and various applications. In addition, this supports a firmware upgrade capability through UART. An FPGA and an ASIC implementation of this module, designed as soft If, are tested for file and bit-stream transfers between PCs.

A Coexistence Mitigation Scheme in IEEE 802.15.4-based WBAN (IEEE 802.15.4 기반 WBAN의 공존 문제 완화 기법)

  • Choi, Jong-hyeon;Kim, Byoung-seon;Cho, Jin-sung
    • Journal of Internet Computing and Services
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    • v.16 no.3
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    • pp.1-11
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    • 2015
  • WBAN(Wireless Body Area Network) operating around the human body aims at medical and non-medical service at the same time. and it is the short-range communication technology requiring low-power, various data rate and high reliability. Various studies is performing for IEEE 802.15.4, because IEEE 802.15.4 can provide high compatibility for operate WBAN among communication standard satisfiable these requirements. Meanwhile, in the case of coexisting many IEEE 802.15.4-based WBAN, signal interference and collision are the main cause that is decreasing data reliability. but IEEE 802.15.4 Standard does not consider about coexistence of many networks. so it needs improvement. In this paper, To solve about this problem, identify coexistence problem of IEEE 802.15.4-based WBAN by preliminary experiments. and propose a scheme to mitigate the reliability decrease at multiple coexistence WBAN. The proposed scheme can be classified in two steps. The first step is avoidance to collision on the CFP through improving data transmission. The second step is mitigation collision through converting channel access method. Proposed scheme is verified the performance by performing comparison experiment with Standard-based WBAN.

Standardization Plans for Consolidated Implementation of ITS Technology (ITS 기술의 통합적 구축을 위한 표준화 방안 연구)

  • Park, Yong-Seo;Lee, Jae-Kyoung;Lee, Jin-Ho;Kang, Byeong-Gwon
    • Journal of Digital Convergence
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    • v.11 no.7
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    • pp.149-155
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    • 2013
  • Recently, automobile traffic systems are evolving toward Intelligent Traffic Systems(ITS) with smart sensor technology and collaboration between traffic systems and external ones. On the contrary, Korean ITS services have little improvement comparing with other communication services. The main causes of this phenomenon are due to already allocation of ITS recommended frequency band to broadcasting services, and also dedication of DSRC frequency band over ISM band resulting in interferences. This paper provides the analysis of current Korean ITS technology status, and two suggestions to activate the ITS industry. First, need to fix the ITS standard combining WAVE and DSRC specifications soon. Second, ITS frequency allocation to complete its standard implementation in near time frame.

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
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    • v.18 no.2
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    • pp.19-28
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    • 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.