Showing papers by "Cheol-Sig Pyo published in 2007"

Localization apparatus for recognizing location of node in sensor network and method thereof

Abstract: Provided are a localization apparatus for recognizing a location of a node in a sensor network and a method thereof. The method includes the steps of: a) selecting reference nodes from a plurality of anchor nodes to be used for triangulation; and b) obtaining location information of a target node by performing triangulation using the selected reference node, wherein in the step a), the reference nodes are selected by removing anchor nodes having obstacle factor from a plurality of the anchor nodes where the obstacle factor causes error in a distance measured by the target node.

Passive tag including volatile memory

Abstract: A passive tag including a volatile memory is provided. The passive tag includes: a sensing unit which senses or measures information about environmental surroundings of the tag; a volatile memory; a non-volatile memory; and a control unit which firstly stores resultant data sensed or measured by the sensing unit in the volatile memory and then moves the data stored in the volatile memory to the non-volatile memory according to pre-set conditions. Therefore, the life of the tag is prolonged and stability of important data can be secured.

Passive RFID reader and operation control method therefor

Abstract: Provided is a Radio Frequency Identification (RFID) reader that can minimize collision among RFID readers in an environment where there are a plurality of RFID readers within a limited operating environment by making each RFID reader select a channel at different delay time based on a random value, and a method for controlling operation of the RFID reader. The RFID reader includes a random value generating unit; a reader control unit for adaptively deciding a counter value for generating the random value; an anti-collision unit for preventing collision among a plurality of tags; a reader transmitting unit for generating a reader command message determined by the anti-collision unit, encoding the reader command message, and modulating the reader command message; a reader receiving unit for demodulating and decoding a tag signal; and a channel operation control unit for selecting a channel to be used for the communication with the tag.

Apparatus and method of generating wake-up signal in battery-powered passive tag

Abstract: An apparatus and method of generating a wake-up signal from a passive tag with a battery is provided. According to the present invention, since a wake-up signal is generated by a signal received from a Radio Frequency Identification ( RFID) reader, battery life can be extended. That is, a wake-up signal can be generated for the battery to be operated according to a signal from the RFID reader so that the battery included in the tag can be controlled from the RFID reader, thereby controlling the amount of battery power consumed. Therefore, the battery life and the life of the tag including the battery can be increased.

Method of preventing data collisions in beacon-enabled zigbee system having tree routing scheme

Abstract: Provided is a method of preventing a data collision that occurs when two or more child nodes simultaneously transmit data to a parent node in a ZigBee network having a tree routing scheme and operating in a beacon mode. In the ZigBee system having the tree routing scheme and operating in the beacon mode, data communication to the parent node is performed in a beacon frame of the parent node. Here, when several child nodes exist under a single parent node, the child nodes transmit data to the parent node at the moment of receiving the beacon of the parent node, so that the data collision may occur when the child nodes simultaneously transmit the data to the parent node in the beacon frame of the parent node. In the method of preventing a data collision, each of the two or more child nodes is set to wait for its guard time (delay time) when transmitting data to the parent node to induce a normal slotted carrier sense multiple access with collision avoidance (CSMA-CA) operation. Therefore, the data collision can be prevented.

Apparatus and method for integrated reader and tag

Abstract: Provided are a reader-tag integrated RFID apparatus and a method for controlling the same. The apparatus includes a tag unit for communicating with an external reader, and transmitting a response signal and data corresponding to a signal transmitted from the external reader to the external reader, a reader unit for selecting a channel between other reader and the reader-tag integrated RFID apparatus with a different delay time, and communicating with an external tag using a random value to minimize collision; and a controller for selectively activating one of the tag unit and the reader unit if it necessary.

An advanced RFID system to avoid collision of RFID reader, using channel holder and dual sensitivities

Abstract: Recently, RFID system has become popular and has been growing rapidly. Due to using many readers in limited area, RFID reader collision problem occurs when the reader is interfered with the signals from neighbor readers or other devices. Even if 50 channels are available in North America, 15 channels in Europe and 25 channels in Korea are available. Moreover, in the future, if many mobile (cellular) RFID readers might be used in limited area simultaneously, the number of channels is not enough, and the collision problem might be more serious. Therefore, this paper proposes an advanced RFID system with a channel holder and dual reader sensitivities/reduced reader output power. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2643–2647, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22808

Method of performing medium access control (mac) and allocating resources to nodes in wireless ad hoc network, and computer-readable recording medium storing frame structure for executing the method

Abstract: Provided is a recording medium for storing a structure of a frame for performing Medium Access Control (MAC) and allocating resources in a multi-hop wireless Ad hoc network, and a method of performing Medium Access Control (MAC) and allocating resources in a multi-hop wireless Ad Hoc network. The method includes performing initialization of communication by receiving or transmitting a Request-To-Send (RTS) message and a Clear-To-Send (CTS) message from or to a node that is to be communicated with in the multi-hop wireless Ad hoc network; constructing a frame comprising at least one slot comprising an initialization field for performing the initialization of communication, a high level link region for communication between Full Function Device (FFD) nodes in the multi-hop wireless Ad hoc network which exist within a one-hop distance in the multi-hop wireless Ad hoc network, and a low level link region for communication between Reduced Function Device (RFD) nodes in the multi-hop wireless Ad hoc network which exist within a one-hop distance from the reference FFD node; allocating the resources to the frame on the basis of data types, priorities, and estimated interference values; and performing communication between nodes in the multi-hop wireless Ad hoc network within the length of the frame, and then returning to the operation of performing initialization of communication. Therefore, by effectively executing MAC and allocating resources according to a variety of data requests, it is possible to improve the reliability and Quality of Service (QoS) of the multi-hop wireless Ad hoc network and reduce power consumption.

Apparatus for storing sensing data in tag and method thereof

Abstract: An apparatus for storing sensing data in a tag and a method thereof are provided. According to the present invention, data measured by the sensor is stored in volatile memory and important data from among the data stored in the volatile memory is stored in non-volatile memory according to a pre-set data loss prevention mechanism so that a battery and the tag including the battery have a longer life and stability of data can be secured.

Method for transmitting sensor data in sensor network including pair node

Abstract: Provided is a method for transmitting sensing information in a wireless sensor network including a pair node. The method for transmitting sensing information in a wireless sensor network including a sink node, parent nodes, and sensor nodes set as pair nodes among sensor nodes connected to the parent nodes, includes the steps of: a) setting up predetermined sensor nodes in the same target area as pair nodes for transmitting and receiving sensing information to/from corresponding sensor nodes; b) at the pair nodes, transmitting first sensing information sensed by oneself to corresponding sensor nodes; c) at the sensor nodes, transmitting first sensing information sensed by oneself and second sensing information transmitted from corresponding pair nodes to the parent node; and d) at the parent node, transmitting the received first and second sensing information to the sink node at the same time.

Antenna Using Proximity-Coupling Between Radiation Patch and Short-Ended Feed Line, Rfid Tag Employing the Same, and Antenna Impedance Matching Method Thereof

Abstract: Provided is an antenna based on proximity coupling between a short-ended microstrip feed line and a radiation patch, an RFID tag including the planar antenna, and an antenna impedance matching method thereof. The antenna includes a radiation patch configured to determine a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeding part disposed between the radiation patch and the ground plate and configured to provide radio frequency signals to a device connected to the antenna. The feeding part includes a feed line that is formed in a resonance length direction of the radiation patch and proximity-coupled with the radiation patch and one end of the feed line is shorted. The antenna freely controls the resistance and reactance of the antenna impedance independently and efficiently matched to a device connected to the antenna which has a predetermined impedance in wide bands.

Node synchronization system for low-power in sensor network and method thereof

Abstract: Provided are a node synchronization system for low-power in a sensor network and a method thereof. The node synchronization system includes: a network transmitting means for transmitting information on a synchronization time difference to the sensing data collecting means and transmitting sensing data to a network; the sensing data collecting means for receiving synchronization time information from the network transmitting means, being synchronized with the network transmitting means, collecting the sensing data from a sensing means, and transmitting the sensing data to the network transmitting means; and the sensing means for receiving synchronization time information from the sensing data collecting means, being synchronized with the sensing data collecting means, sensing a sensing peripheral environment information, and transmitting the sensing data to the sensing data collecting means.

Method for determining superframe for beacon scheduling

Abstract: Provided is a method for determining superframe to efficiently perform beacon scheduling by allocating superframe lengths which are different according to a routing depth of sensor nodes in a ZigBee based wireless sensor network. The method for determining a superframe for beacon scheduling, includes the steps of: receiving a beacon from a neighboring node and grasping information on a superframe used by the neighboring nodes; and determining a transmission time and a length of own superframe based on superframe information of the grasped neighboring node.

Method for reading tag in mobile rfid environment

Abstract: Provided is a method for reading a tag in a mobile Radio Frequency Identification (RFID) environment. The tag reading method effectively identifies a tag by repeatedly transmitting a tag identification request in a predetermined time to prevent collision among RFID readers, when a plurality of RFID readers access to a tag. The method for reading a tag in a mobile RFID environment, which includes the steps of: a) transmitting a tag identification request signal to a tag; b) waiting for an acknowledgement signal to be transmitted from the tag; and c) when no acknowledgement signal is transmitted from the tag, retransmitting the tag identification request signal after a predetermined delay time passes.

System and method for guiding visitor using sensor network

Abstract: Provided are a system and method for guiding a visitor using a sensor network. The system includes: an entry approval requesting unit for requesting an entry approval of the visitor to the visitee terminal according to destination information; a route setting unit for setting a route along which the visitor terminal is to move to the destination, based on the destination information of the visitor, according to an entry approval result of the visitee terminal; a location detecting unit for detecting a current location of the visitor terminal based on identification information of the visitor terminal and location information of the sensor node, the identification information and the location information being obtained through the sensor network on the route; and a location confirming unit for confirming if the detected current location of the visitor terminal is out of a preset area.

Remote control method of sensor node for low-power and sensor network therefor

Abstract: Provided are a remote control method of a sensor node for low-power and a sensor network therefor. The remote control method, including: generating an interrupt signal when a node receives a remote control signal from a corresponding micro radio frequency (RF) processor installed in a gateway; regenerating the interrupt signal when the node is not converted from a sleep mode to a wake-up mode; collecting sensing data by communicating with other nodes when the node is converted from the sleep mode to the wake-up mode; and converting from the wake-up mode into the sleep mode when the communication is completed.

Apparatus and method for collecting shopping information using magnetic sensor

Abstract: Provided are an apparatus and method for collecting shopping information using a magnetic sensor. The shopping information collecting apparatus, includes: a magnetic value sensing and analyzing means for sensing and analyzing a magnetic value within own zone in real-time; a central processing means for processing shopping information based on the magnetic value analyzed by the magnetic value sensing and analyzing means; and a shopping information transmitting means for transmitting shopping information processed by the central processing means.

Method for identifying multiple moving tags with multiple readers

Abstract: Disclosed is a method for identifying a plurality of moving tags by using a plurality of Radio Frequency Identification (RFID) readers. The technology of the present invention efficiently identifies multiple moving tags to thereby improve the identification rate and reading speed of an RFID system and increase the throughput of the RFID system. The method for identifying a plurality of moving tags by using a plurality of Radio Frequency Identification (RFID) readers includes the steps of: a) grouping the multiple tags into a predetermined number of tag groups; b) allocating the tag groups to the RFID readers respectively; and c) identifying tags of each allocated tag group in each RFID reader.

System with shared power amplifier for mobile communication terminal with mobile rfid function

Abstract: Provided is a power amplifier sharing system for a mobile communication system having a mobile Radio Frequency Identification (RFID) function, particularly, a power amplifier sharing system that can reduce the power consumption and the size of a circuit in a mobile communication terminal having a mobile RFID function. The system includes a mobile communication transceiver for transmitting/receiving a mobile communication signal; a mobile RFID transceiver for transmitting/receiving a mobile RFID signal; a power amplifier for amplifying a signal; a switch for connecting the mobile communication transceiver and the mobile RFID transceiver to the power amplifier; and a transceiver controller for controlling the switch and the power amplifier.

Method of constructing tree network

Abstract: Provided is a method of constructing a tree network which includes a first node. The method comprises: (a) the first node determining if there is a child node and requesting a parent node to allow the first node to withdraw if there is no child node; (b) selecting a child node based on remaining amounts of battery power of each child node if there are child nodes of the first node; (c) exchanging positions of the first node and the selected child node and requesting the parent node to allow the first node to withdraw if the child node selected in operation (b) does not have child nodes; and (d) repeating operations (b) and (c) if the child node selected in operation (b) has child nodes. The present invention solves the problem of decreasing lifetimes of upper nodes that consume more battery power than lower nodes due to more traffic transmission and reception.

Node synchronization system for low-power in the sensor network and its method

Abstract: A synchronization system of a sensor network for low power and a method thereof are provided to transmit data after synchronizing each node of the sensor network, and to perform transition into a sleep mode again, thereby reducing power consumption of nodes. Synchronization is prepared as a packet informing of starting of the synchronization is received(601,602). A packet to be substantially synchronized as including synchronization time information is received(603). The synchronization is performed on the basis of the synchronization time information within the packet to be substantially synchronized(604).

Matching system and method for preventing the loss of data between low-power network and non-low-power network

Abstract: There is provided a matching system for preventing the loss of data between a low-power network and a non-low-power network, the matching system including: an RF communication schedule management unit, installed in the low-power network side system, for managing a schedule of an RF communication period indicative of a data transmission period of the low-power network; a heterogeneous network communication schedule management unit, disposed in the non-low-power network side system, for creating a schedule to transmit data to the low-power network side system based on the RF communication period provided by the RF communication schedule management unit; and a heterogeneous network communication unit for transmitting the data to the low-power network side system depending on the schedule created by the heterogeneous network communication schedule management unit.

Linearizer for ubiquitous sensor node

Abstract: Provided is a linearizer for a transmitting/receiving system of a low-power sensor node in a ubiquitous sensor network. The linearizer includes: a predistortion element configured to receive a linear RF signal to be transmitted, predistort the received linear RF signal according to a distortion characteristic opposite to that of the nonlinear RF element, and output the predistorted RF signal to the nonlinear RF element.

Method and system of guiding a visitor using a sensor network

Abstract: A method and a system for guiding a visitor using the sensor network are provided to guide the visitor from a starting position to a destination position or from the destination position to the starting position through a visitor terminal by using the sensor network constructed in a building. An entry approver requests entry of a visitor to a terminal(70) of a person to visit according to destination information received from the visitor. A course setting part sets a course for guiding the visitor terminal(10) to the destination position by using the destination information of the visitor according to an approval of the terminal of a person to visit. A location searcher searches and provides a current position of the visitor terminal by using a visitor terminal ID obtained through the sensor network and location information of a sensor node(20) communicating with the visitor terminal. A location checker checks whether the present location of the visitor searched from the location searcher is out of a predetermined range. A door controller enables the visitor terminal to open/close a door installed at the destination position.

Method and apparatus for assigning channel in ad-hoc network

Abstract: The present invention provides a method and apparatus for assigning a channel in an ad-hoc network, which can minimize beacon collision in the ad-hoc network and prevent channel overlapping or collision, and thus a channel can be efficiently assigned. The method of assigning a channel including: obtaining join order information which is information on the order in which a first node has been joined to a second node, which is a parent node, and level information of the second node in an ad-hoc network; determining a reference value for setting a channel that is to be assigned to the first node based on an address value of the first node, which is determined based on the join order information and the level information, a level value of the first node, a channel value of the second node, which is determined based on the level information, and the join order information; and determining a channel value of the first node by dividing the reference value by the maximum number of usable channels in the ad-hoc network.