Showing papers by "Cheol-Sig Pyo published in 2006"

Novel U-slot and V-slot DGSs for bandstop filter with improved Q factor

Abstract: Novel slot-shaped defected ground structures (DGSs) on the microstrip line are presented to provide a band-rejection property with an improved Q factor. Two different geometries (U-slot and V-slot) are investigated. U-slot and V-slot DGSs have simple shapes compared to the conventional DGSs, however, they provide more steep rejection characteristics. The Q factor of the band-rejection property for the U-slot DGS increases when the distance between two slots in the U-shape decreases. Similarly, the V-slot DGS provides a higher Q characteristic when the slot angle is reduced. Two bandstop filters are designed and fabricated employing three cascaded U-slot DGSs and V-slot DGSs, respectively. Experimental result shows that the high-Q band-rejection filter with three U-slot DGSs provides Q of 38.6. A fabricated filter with three cascaded V-slot DGSs also rejects the signals at the frequencies from 3.5 to 4.3 GHz with more than 20-dB suppression

A Low-Power RF Direct-Conversion Receiver/Transmitter for 2.4-GHz-Band IEEE 802.15.4 Standard in 0.18- $\mu{\hbox {m}}$ CMOS Technology

Abstract: This paper presents a low-power RF receiver/transmitter front-end for 2.4-GHz-band IEEE 802.15.4 standard in 0.18-mum CMOS technology. An RF receiver comprises a single-ended low-noise amplifier, a quadrature passive mixer, and a transimpedance amplifier. A current-mode passive mixer showing a very good 1/f noise performance is adopted to convert an RF signal directly to a baseband signal. Moreover, this type of passive mixer shows high-linearity performance, leading to overall RF receiver linearity improvement. A low-power, high-linearity transmitter front-end is implemented by using a passive mixer and two-stage driver amplifier in which the first stage is a conventional cascode amplifier and the second stage uses a folded cascode one. The receiver front-end achieves 30-dB voltage conversion gain, 7.3-dB noise figure with 1/f noise corner frequency of 70 kHz, -8-dBm input third-order intercept point, and +40-dBm input second-order intercept point. The transmitter front-end shows 12-dB power conversion gain, 0-dBm output power with 10-dBm output third-order intercept point, and -30-dB local-oscillator suppression. The receiver and transmitter front-end dissipate 3.5 and 3 mA from a 1.8-V supply, respectively

Wireless sensor network and adaptive method for monitoring the security thereof

Abstract: The present invention relates to a sensor network having node architecture for performing trust management of neighboring sensor nodes, and to an adaptive method for performing trust management of neighboring sensor nodes for monitoring security in the sensor network. The sensor network includes a base station and a plurality of sensor nodes for reporting sensed information packets to the base station through radiofrequency signals relayed by other sensor nodes. A judge sensor node may have a trust estimator in its node architecture to evaluate trustworthiness of a neighboring suspect sensor node by determining a personal reference and receiving personal references from jury sensor nodes. Based on the trustworthiness of the suspect, the judge may modify a route for transmitting packets to the base station.

Design of wideband RFID tag antenna for metallic surfaces

Abstract: A low-cost wideband antenna for radio frequency identification (RFID) tags mountable on metallic surfaces is presented. A novel proximity-coupled feed structure, in which the direction of the microstrip feedline is orthogonal to that of the resonant length of the radiating patch, is explored to perform simple and wideband impedance matching between an antenna and a tag chip without any additional matching networks. The proposed design is verified by simulation and measurement, which show good agreement.

Method for securing information between RFID reader and tag, and RFID reader and tag using the same

Abstract: Provided is a method for securing information between a Radio Frequency Identification (RFID) reader and tag, and an RFID Reader and tag using the same. The method includes the steps of: a) requesting an access password of the RFID tag in the RFID reader; b) extracting a key value mapped to the access password transmitted from the RFID tag and transmitting the key value to the RFID tag in the RFID reader; c) outputting a hash function value from the key value transmitted from the RFID reader in the RFID tag; and d) determining whether to allow the RFID reader to access to an RFID tag memory based on whether the outputted hash function value is the same as the access password of the RFID tag.

Apparatus and method for receiving tag signal in mobile RFID reader

Abstract: Provided are a tag signal receiving apparatus that can perform digital Amplitude Shift Keying (ASK) demodulation onto signals received in a tag, decode the demodulated tag signal in synchronization, and acquire tag data in a mobile RFID reader, and a method thereof. The tag signal receiving apparatus includes: a digital demodulating block for performing ASK demodulation onto a digital tag signal received through a reader antenna and converted into a digital tag signal in an analog-to-digital (AD) converter; and a decoding block for detecting edge position information of the demodulated tag signal by performing accumulation and decoding the demodulated tag signal by using the detected edge position information. The digital demodulating block includes a channel level comparator, a phase inverter, a signal converter; and an adder. The decoding block includes an edge information detector, a correlator, and a bit data decider.

Data storing apparatus and method for RFID tags with sensors

Abstract: Provided is a data storing apparatus and method for Radio Frequency Identification (RFID) tags with sensors. The apparatus includes: a first storing block which includes a kill password storage and an access password storage; a second storing block which includes an Electronic Product Code (EPC) storage, a protocol control storage, and an error check storage storing a Cyclic Redundancy Checking (CRC) code for detecting a transmission error; a third storing block which includes a tag identifier storage storing a tag identifier including a manufacture model and a serial number of the tag; and a fourth storing block which includes an initial sensor data storage storing initial information of the sensor, a real-time information storage, a maximum/minimum data storage storing maximum/minimum values, a sensor data storage storing sensing data actually measured through the sensor embedded in the RFID tag.

Method for estimating number of tags in slotted aloha-based RFID system

Abstract: Provided is a method for estimating the number of tags in a slotted Aloha-based RFID system, which can estimate the number of tags through a new statistical average scheme using the number of slots, the measured number of empty slots, and the measured number of ID slots. The estimating method includes the steps of: a) setting the number (N) of slots, the measured number (c 0 ) of empty slots, and the measured number (c 1 ) of ID slots as parameters; and estimating the number (n) of the tags by substituting the set values into n=(N−1)/(c 0 /c 1 ).

Open-ended two-strip meander line antenna, RFID tag using the antenna, and antenna impedance matching method thereof

Abstract: An open-ended two-strip meander line antenna, an RFID tag using the same and an antenna impedance matching method thereof are provided. The antenna includes: a radiating strip line for deciding a resonant frequency of the antenna; and a feeding strip line for providing a radio frequency (RF) signal to an element connected to the antenna, wherein ends of the radiating strip line and the feeding strip line are open.

Mobile RFID service providing apparatus and method thereof

Abstract: Provided is a mobile Radio Frequency Identification (RFID) service providing apparatus and a method thereof. The apparatus, includes: a policy server for establishing a policy on level of quality of service (QoS) to be provided to each user, and a policy to be applied between nodes for security; an Authentication, Authorization and Accounting (AAA) server for performing network access authentication and authorization to each user, authorization for a mobile RFID service, security association establishment and distribution between constituent nodes based on information of the policy server; a mobile RFID agent for performing a diameter client role and a mobile RFID service agent role; and a service server for searching uniform resource locator (URL) of a server providing information related to an RFID code and providing detailed information and history information to the mobile RFID phone.

Apparatus and method for computing location of a moving beacon using time difference of arrival and multi-frequencies

Abstract: Provided is an apparatus and method for computing the location of a radio beacon by using Time Difference Of Arrival (TDOA) and multiple frequencies. The apparatus and method of the present invention compute the location of a radio beacon without limitation in distance by using multiple frequencies and time difference of arrival to resolve the problem of phase ambiguity. A radio beacon location computing system includes a plurality of base stations configured to receive signals of multiple frequencies transmitted from the radio beacon, and detect and output phase differences and arrival time; and a location computing server configured to receive the phase differences and the arrival time outputted from the respective base stations, acquire calculation distances based on the phase differences, remove phase ambiguity from the calculation distances based on the arrival time, and compute the location of the radio beacon.

Method for selecting desired item information in mobile terminal

Abstract: Provided is a method for selecting only desired item information in a mobile terminal. The method includes the steps of: a) setting up an item category desired and selected by a user in the mobile terminal; b) reading item information stored in tags attached to items with a Radio Frequency Identification (RFID) reader loaded in the mobile terminal; and c) performing filtering and displaying only the item information of an item that belongs to the selected item category among the item information acquired by the RFID reader of the mobile terminal.

Distributional alert system for disaster prevention utilizing ubiquitous sensor network

Abstract: Provided is a distributional alert system using a ubiquitous sensor network (USN). When a disaster occurs, the distributional alert system detects it in a sensor node, informs the area where the disaster occurs of danger through an actuator, such as siren, or informs a management system of the danger through a wired/wireless network. The distributional alert system includes: a first sensor node for generating sense data by sensing surroundings with a sensor therein, determining whether a disaster occurs by analyzing the sense data, and creating and transmitting emergency data based on the determination result, while forming a sensor network; and an alerting node for receiving emergency data from the first sensor node on the sensor network, and outputting disaster circumstantial information to a sensor field of the sensor network upon receipt of the emergency data.

Rfid Tag for Ip Address-Based Rfid Service and Rfid Service Method Using the Same

Abstract: Provided are an RFID tag and a method for providing an RFID service using the same. The RFID tag includes: a code type data denoting a code type of the RFID tag; and a content server IP address code denoting an IP address of a content server that provides content related to an item with the RFID tag attached.

Mobile RFID reader and control method thereof

Abstract: Provided are a mobile RFID reader and a control method thereof. The mobile RFID reader includes: a reader controller for beginning a reader operation to communicate with a tag in response to a command of a terminal controller of the wireless communication terminal; an anti-collision state machine for controlling collision among a plurality of tags, and transferring the result of communication with the tag to the reader controller; a reader transmitter for generating a reader command message decided at the anti-collision state machine, and coding and modulating the generated reader command message; a reader receiver for demodulating and decoding a tag signal received through an antenna, and reporting a tag response state to the anti-collision state machine; and a channel controller for selecting a channel to use to communicate with a tag in response to a command of the reader controller.

A low-cost, wideband antenna for passive RFID tags mountable on metallic surfaces

Abstract: A low-cost, wideband planar antenna for RFID tags mountable on metallic surfaces has been presented in this paper. A novel proximity-coupled feed structure, in which the direction of the microstrip feedline is orthogonal to that of the resonant length of the radiating patch, has been explored to perform simple and wideband impedance matching between an antenna and a tag chip without any additional matching networks. The prototype of the antenna was fabricated and measured, and 57 MHz bandwidth at 3 dB return loss has been achieved.

Method for Managing Dormant Nodes in Wireless Sensor Network

Abstract: Provided is a method for managing dormant nodes in a wireless sensor network. The method includes the steps of: a) acquiring and storing information on distance and location of sensor nodes registered in a corresponding cluster among at least one cluster managed by a managing node; b) selecting a dormant object node among the sensor nodes by the managing node; c) transmitting dormant information that the dormant object node should go into a dormant state for a predetermined period through a beacon message to the dormant object node and creating a dormant node management table; and d) updating a dormant time of the dormant node management table every beacon cycle by the managing node according to setup of a dormant time central managing function and notifying dormancy expiration to the corresponding dormant node.

Design and implementation of mobile RFID technology in the CDMA networks

Abstract: This paper describes the mobile RFID technology for E-business as focusing on design and implementation. Last year, the rate of Internet accessible mobile phones in Korea was 89.5% but the rate of utilizing mobile wireless Internet was 28%. The packet price in the wireless communication, lack of diversity of contents, and uncomfortable user interface restricts access to the services in the wireless Internet. To solve the following problem such as lack of diversity of contents and uncomfortable user interface we propose mobile RFID technology. Until now, many RFID technologies have been developed rapidly in the control of goods in stock and the marketing structure. However we suggest the mobile RFID technology to extend RFID technologies with the high quality mobile environments in Korea.

Power control method for mobile RFID reader and RFID reader using the same

Abstract: Provided is a power control method for a mobile Radio Frequency Identification (RFID) reader and an RFID reader using the same. The RFID reader includes: an RFID reader transmission/reception control unit for creating a message to be transmitted to an RFID tag and transmitting RFID tag information to a terminal control unit; a reader transmitting unit for encoding and modulating the created message; a power amplifier for amplifying an output signal; a reader receiving unit for demodulating and decoding the signal and transmitting the signal to the RFID reader transmission/reception control unit; and an RFID reader power control unit for controlling power, wherein when the RFID reader transmission/reception control unit receives a command for acquiring the RFID tag information, the RFID reader power control unit applies power to the power amplifier.

Apparatus and method for computing location of a moving beacon using received signal strength and multi-frequencies

Abstract: Provided is an apparatus and method for computing the location of a radio beacon by using received signal strength (RSS) and multiple frequencies. The apparatus and method of the present invention computes the location of a radio beacon without limitation in distance by using multiple frequencies and received signal strength to resolve the problem of phase ambiguity. A radio beacon location computing system includes a plurality of base stations configured to receive signals of multiple frequencies transmitted from the radio beacon, and detect and output phase differences and received signal strength; and a location computing server configured to receive the phase differences and the received signal strength outputted from the respective base stations, acquire calculation distances based on the phase differences, remove phase ambiguity from the calculation distances based on the received signal strength, and compute the location of the radio beacon.

Apparatus and method for reading multiple tags with different protocols in RFID system

Abstract: An apparatus and method for reading multiple tags with different protocols in a RFID system are provided. The method of reading multiple tags with different protocols in a RFID system including the steps of: a) setting scheduling parameters including target protocols to read, priorities of each protocol, and information about a scheduling algorithm mode for reading multiple tags; b) reading tags of a single protocol corresponding to the target protocol when the scheduling algorithm mode is a single mode; and c) reading multiple tags by the target protocols when the scheduling algorithm mode is a multi mode.

Method and Apparatus For Transmitter Locating Using a Single Receiver

Abstract: Provided is a method and apparatus for locating a transmitter. The apparatus for locating a transmitter, including: an antenna having an antenna array for receiving first and second frequency signals transmitted from the transmitter and measuring an angle of the transmitter; a range of transmission (ROT) calculating unit for calculating the range of transmission of the transmitter based on phase difference between the first and second frequency signals; an angle of arrival (AoA) calculating unit for calculating the angle of the transmitter based on phase difference of common frequency signals received in the antenna; and a transmission location determining unit for determining the location of the transmitter based on the range of transmission and the angle of arrival of the transmitter.

Antenna using proximity-coupled feed method, RFID tag having the same, and antenna impedance matching method thereof

Abstract: An antenna, a RFID tag using the same, and an antenna impedance matching method thereof are provided. The antenna includes: a radiation patch for deciding a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeder disposed between the radiation patch and the ground plate in parallel for providing a RF signal to an element connected to the antenna, wherein the feeder includes a microstrip feed line proximately coupled to the radiation patch by being formed perpendicularly to the resonant length direction of the radiation patch.

Method and apparatus for sharing portable terminal in CDMA system and mobile RFID system

Abstract: Provided are a method and apparatus for sharing a portable terminal in a Code Division Multiple Access (CDMA) and a mobile Radio Frequency Identification (RFID) system. The portable terminal includes: a CDMA mobile station system for performing CDMA communication; a mobile RFID system for performing a passive RFID reader function; a switching unit for switching an antenna to any one between the CDMA mobile station system and the mobile RFID system; and a control unit for controlling the switching unit to connect the antenna to the CDMA mobile station system when the portable terminal transmits/receives a signal to/from the base station, or connect the antenna to the mobile RFID system when the portable terminal transmits/receives a signal to/from an RFID tag.

Method for processing reception call in mobile RFID service, and a wireless communication terminal employing the same

Abstract: Provided are a method for processing reception calls during mobile RFID service processing, and a wireless terminal employing the method. The terminal provides mobile RFID service by receiving tag information from the RFID reader, requesting the object directory server for CS position information based on the tag information, requesting service contents based on the tag information and CS position information. The present invention prevents collision between reception call processing and mobile RFID service processing in the wireless terminal by processing reception call appropriately to each duration of mobile RFID service processing. For example, when a call is received before read command is transmitted to the RFID reader, the RFID reader is turned off and the reception call is processed. When a call is received before CS position information is requested, the CS position information is requested after the reception call is processed.

MAC forwarding method for multi-hop routing in communication system between vehicles

Abstract: Provided is a Media Access Control (MAC) forwarding method for multi-hop routing in a communication system between vehicles The method includes the steps of: a) receiving a frame from all nodes and checking whether there are duplicate frames; b) partly updating forwarding cache table (FCT) information, or updating SNT information and checking whether a destination address is a corresponding node; c) updating the FCT information, transmitting an Ack signal and transferring the frame to the upper layer, or searching whether the destination address is registered as “d_addr”; d) updating the FCT information and transmitting a delay ACK frame or checking whether the transmitted frame is a flooding frame; and e) updating the FCT information, checking whether the other node does not transmit the “d_ack” and inserting a flooding frame, otherwise, updating the FCT information and abandoning the frame

Method for buffering receive packet in media access control for sensor network and apparatus for controlling buffering of receive packet

Abstract: Provided is a method for buffering a receive packet in a sensor node including a radio frequency (RF) transceiver, a media access control (MAC) hardware block and a micro controller unit (MCU) The method includes the steps of: a) if a packet is received from the RF transceiver, checking whether or not a packet which is pre-stored in a receive first in first out (FIFO) exists; b) if the pre-stored packet exists in the receive FIFO at step a), checking whether a length of the received packet is the same with the length of the pre-stored packet in the receive FIFO; c) if the length of the received packet is the same with the length of the pre-stored packet in the receive FIFO at the step b), increasing the number of packet which is included in header information, and buffering a physical payload in the receive FIFO; and d) if the pre-stored packet does not exist in the receive FIFO at the step a) nor the length of the received packet is the same with the length of the pre-stored packet in the receive FIFO, consecutively buffering the physical payload with the header in the receive FIFO

Electrical loop antenna with unidirectional and uniform current radiation source

Abstract: Provided is an antenna for a Radio Frequency Identification (RFID) reader using an electrical loop. It includes an upper metal plate which functions as a radiator; a lower metal plate which is disposed apart from the upper metal plate by a predetermined distance and functions as a radiator; a ground plate disposed apart from the lower metal plate by a predetermined distance; and a feeding probe disposed at the center of the upper and lower metal plates. The antenna can perform radiation parallel to the earth's surface including other directions. Therefore, it is suitable for an RFID reader which recognizes an RFID tag attached in parallel to the earth's surface. The electrical loop antenna can control impedance matching, resonance frequency, antenna gain, and radiation pattern according to the distance between metal plates, size of the metal plates, thickness of a feeding probe, and how the metal plates are arranged.

Rfid tag data storing apparatus with internal sensor

Abstract: An RFID(Radio Frequency IDentification) tag data storage device embedded with a sensor is provided to efficiently manage all desired information by fully saving a memory space, as data inputted through the sensor in real-time is stored to a memory after processing. A reserved part(210) includes a kill password repository(211) storing a kill password sent to an RFID tag from an RFID reader to stop an operation of the RFID tag and an access password repository(212) storing an access password of the RFID tag. An EPC(Electronic Product Code) part(220) includes a code repository(223) storing a code for identifying an object attaching the RFID tag, a protocol control repository(222) storing physical layer information of the code repository, and an error check repository(221) storing a CRC(Cyclic Redundancy Check) code for detecting a transfer error. A tag ID part(230) includes an RFID tag repository(231) storing an RFID tag ID including a model and a serial number of the RFID tag. A user memory part(240) includes an initial sensor data repository, a real-time information repository, an upper/lower limit data repository, and a sensor data repository.