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.

Abstract: A method and apparatus using a synchronous sensor network medium access control (MAC) protocol, such as a ZigBee or IEEE 802.15.4 low-rate wireless personal area network (WPAN), is disclosed. A method and apparatus for constructing a ubiquitous sensor network (USN) of which a life is increased by using power beacons and reducing the number of unnecessary control packets (beacon packets), thereby reducing an initialization time between nodes and preventing beacon collision, is also disclosed. A beacon packet channel having a large output power and a data channel of which a transmission range is restricted by reducing an output power to be less than that of the beacon packet channel, may be simultaneously used.

Abstract: A wireless network system using a cyclic frame including a beacon period (BP), a mesh contention access period (MCAP), and a slot period (SP). The cyclic frame has a frame structure that shares a channel hopping sequence of a node, thereby sharing the channel hopping sequence that operates as an existing mesh node without generating an additional channel hopping sequence, and supporting mesh and star type topologies together in order to efficiently operate a network.

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.

Abstract: A near-field radio frequency identification (RFID) reader antenna is provided. The near-field RFID reader antenna is intended to separately recognize adjacent items to which a plurality of small RFID tags are attached, such as wines displayed on a shelf in a store or chip trays on casino tables, using a near field. The near-field REID reader antenna includes a dielectric layer, at least one signal line formed on the dielectric layer, a ground surface formed under the dielectric layer, at least one ground line formed under the dielectric layer to be electrically connected to the ground surface in parallel with the signal line, at least one signal stub formed to be electrically connected to the signal line toward the ground line, and at least one ground stub formed to be electrically connected to the ground line toward the signal line in parallel with the signal stub.

Abstract: The present invention relates to a near-field antenna. In an aspect, the near-field antenna may include a dielectric layer, a ground plane formed on one side of the dielectric layer, a plurality of U-shaped slots periodically disposed in the ground plane for radiation, and a microstrip line provided on the other side of the dielectric layer for power feeding. In another aspect, the near-field antenna may include a dielectric layer, a ground plane formed on one side of the dielectric layer, a plurality of U-shaped slots periodically disposed in the ground plane for radiation, and a microstrip line configured to have a plurality of U-shaped slots diverged on the other side of the dielectric layer in parallel for power feeding, have the plurality of U-shaped slots periodically disposed in series in respective diverged lines, and have an end shorted to form standing waves.

Abstract: Provided is a method of determining an operation mode of a node in an ad hoc network. The method includes: monitoring a measured amount of residual energy of the node and comparing the measured amount of residual energy of the node with an amount of residual energy theoretically calculated for the node; identifying an amount of information in a queue included in the node; calculating a relay probability of the node by reflecting the identified amount of information in the queue and the result of comparing the measured amount of residual energy of the node with the theoretically calculated amount of residual energy for the node; and determining the operation mode of the node to be one of a relay mode and a transmission mode, based on the calculated relay probability of the node. The method enables nodes to exchange information about their respective amounts of residual energy and analyze the information without using additional resources and processes.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal.

Abstract: The present invention is enables the high-speed download of a large volume of data stored in a tag memory without a remarkable change in conventional wireless communication techniques. According to one aspect of the present invention, an RFID tag comprises; a transmitting unit for transmitting a download command for instructing the download of tag data stored in a user memory bank of the RFID tag; and a receiving unit for receiving, from the RFID tag, tag data in a plurality of record block units, each of which is smaller than the size of the memory bank.

Abstract: An RFID tag attached to an object and transmitting a signal that corresponds to identification information includes an RFID tag chip that modulates the signal according to the identification information and an RFID tag antenna that transmits the modulated signal. The RFID tag antenna includes a dielectric material, a radiating patch, and a slit. The dielectric material has a polyhedral shape and includes a first surface that contacts the object and a second surface that is parallel with the first surface, the radiating patch is formed on at least a part of the second surface and radiates electromagnetic to waves, and the slit is formed on at least a part of the radiating patch to expose the dielectric material.

Abstract: A method of operating a device capable of periodically hopping a predetermined interval using a channel hopping sequence in order to improve low radio frequency (RF) reliability caused by single frequency based channel access.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal. The method is capable of improving a power efficiency of a mobile station by reducing a peak-to-average power ratio in a mobile communication system.

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.

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.

Abstract: Real-time location tracking apparatus and method using a global positioning system (GPS) signal relay tag is provided. Here, a tag may receive a GPS signal and transmit the received GPS signal to a reader, and the reader may calculate a location of the tag, and thereby a real-time location tracking service may be provided.

Abstract: Provided is a cross-layer routing method in a wireless sensor network including: locating a destination node which is a final destination of data by a source node which generates the data; and determining an optimal relay node among one or more neighboring nodes using their position information for each hop and forwarding the data from the source node to the destination node through the determined relay nodes. Therefore, an effective and stable routing which reduces overheads of additional control messages used for stable data forwarding and reduces collisions in a shared channel by using wireless link layer characteristics can be implemented.

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.

Abstract: A constant amplitude decoding apparatus and method for multiplexed direct-sequence spread spectrum communication system are provided. The constant amplitude decoding apparatus includes: a despreading and demultiplexing module receiving a data stream of a constant amplitude and despreading and demultiplexing the received data stream to restore it to a 2D signal; a decoding module first performing a vertical decoding on the 2D signal and then performing horizontal decoding thereon; a control module determining whether to repeatedly perform vertical decoding and horizontal decoding; and a bit stream information output module outputting the decoding results from the decoding module as a bit stream.

Abstract: An RFID tag includes an antenna and a chip, and the antenna includes a first polygonal dielectric material, first and second microstrip lines partially formed in the first dielectric material, a second polygonal dielectric material stacked on the first dielectric material, and a third microstrip line partially formed in the second dielectric material. According to the present invention, the RFID tag can efficiently receive electromagnetic waves to thereby maximize a readable range.

Abstract: A method for converting source data to a channel-modulated signal having a plurality of pairs of in-phase (I) and quadrature-phase (Q) data in a mobile station, wherein the mobile station uses at least one channel, includes the steps of: a) encoding the source data to generate at least one data part and a control part; b) generating at least one spreading code to be allocated to the channel, wherein each spreading code is selected on the basis of a data rate of the data part and the control part and spreading codes are selected so that two consecutive pairs of the I and Q data are correspondent to two points located on same point or symmetrical with respect to a zero point on a phase domain; and c) spreading the control part and the data part by using the spreading code, to thereby generate the channel-modulated signal. The method is capable of improving a power efficiency of a mobile station by reducing a peak-to-average power ratio in a mobile communication system.