摘要:
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.
摘要:
Provided are an apparatus and method for controlling a radiation direction. The apparatus includes parasitic elements disposed in proximity to the antenna, wherein each of the parasitic elements comprises an antenna; a first portion that is inclined with respect to a prepared ground surface at a first angle and a second portion that is inclined with respect to the first portion at a second angle; a lumped element having a variable reactance, which is disposed on each of the first and second portions; and a determination unit controlling the reactance of the lumped element so as to determine the radiation direction of the antenna. By using the apparatus and the method, the antenna has various radiation directions.
摘要:
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.
摘要:
A method for recognizing positions of a plurality of nodes which constitute a wireless sensor network is provided, the method comprises generating sub-maps which represent the relative position to neighbor nodes by taking each of the plurality of nodes as a reference; selecting a sub-map which takes a node with the highest connectivity as a reference from among the plurality of nodes; selecting a sub-map which takes a node with the highest connectivity as a reference, except for the node which becomes a reference of the selected sub-map among the nodes which are included in the selected sub-map; integrating the selected sub-maps into one map by matching the same nodes among the nodes which are commonly included in the selected sub-maps; and thereafter correcting positions of nodes which are included in the integrated map to real positions, whereby integrating order of the sub-map is adjusted using an information of the connectivity of the nodes, and the positions of the nodes which constitute the wireless sensor network is constituted are correctly recognized by correcting the position of the nodes.
摘要:
A multi-path routing method is provided a multi-path routing method for selecting appropriate multiple paths when information sensed from a source node is transmitted to a sink node in wireless sensor networks. The source node for transmitting the sensed information first transmits a Hello message to the sink node to identify the existence and position of the sink node. The sink node receives the Hello message and then re-transmits the Hello message with respect to all the received Hello messages. Respective middle nodes accumulate distances between the middle nodes while the Hello message is transmitted to the source node through a reverse path of the Hello message, and all the middle nodes maintain a real distance from the sink node. The source node receiving all the Hello messages can rout a plurality of appropriate paths through Hop-by-hop to the sink node by providing respective weights to an energy remaining amount, an appropriate transmission radius and a real distance from the sink node. Accordingly, priorities can be provided to lifetime of the source node, average energy consumption and the shortest path by adjusting the respective weights when routing the plurality of paths. In addition, appropriate paths can be routed considering the transmission success rate of a path, and a load balancing effect can be obtained using path cost.
摘要:
A time division multiple access (TDMA) control method used by a mobile radio frequency identifier (RFID) reader through a mobile phone base station and a mobile RFID reader are provided. Each mobile RFID reader occupies a frequency channel during a time slot allocated through a mobile communication base station, thereby avoiding interference between readers.
摘要:
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.
摘要:
Provided is a planar inverted-F antenna (PIFA) which has a Co-Planar Waveguide (CPW) feeding structure and can be attached to a metal surface, and an RFID tag using the same. The PIFA includes a radiation patch layer; a Co-Planar Waveguide (CPW) feeding layer; a feeding probe; and a short-circuit. The CPW feeding layer includes a feeding means and a ground surface. The feeding probe electrically connects the radiation patch layer and the feeding means and provides a Radio Frequency (RF) signal to be radiated to the radiation patch layer. The short-circuiting means short-circuits the radiation patch layer and the ground surface through the dielectric layer. The PIFA can be applied to a passive RFID tag. Impedance matching between the antenna and the RFID chip is possible. Also, the PIFA can easily control resonant frequency of the antenna and reactance.
摘要:
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.
摘要:
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.