摘要:
Provided are an apparatus and method for increasing operation time in an IEEE802.15.4-2006 beacon based wireless sensor network (WSN) with respect to the same amount of power consumption used by coordinators included in a WSN, by reducing unnecessary standby power consumption required during an active period of a super frame in a beacon-enabled mode.
摘要:
Provided are an apparatus and method for increasing operation time in an IEEE802.15.4-2006 beacon based wireless sensor network (WSN) with respect to the same amount of power consumption used by coordinators included in a WSN, by reducing unnecessary standby power consumption required during an active period of a super frame in a beacon-enabled mode.
摘要:
A low power super regenerative receiver and a method of reducing the power consumption of the low power super regenerative receiver are provided. The super regenerative receiver includes: an oscillator having a start-up time period starting oscillation that varies according to an existence of an input signal; and a power controller supplying power within the start-up time period of the oscillator.
摘要:
Provided are a method and an apparatus for avoiding a collision between each of radio frequency identification (RFID) readers. The method and the apparatus divide the RFID readers into first RFID readers and second RFID readers according to a maximum output level, and set first frequency channels for the first RFID readers and second frequency channels for the second RFID readers, set frequency channel disposition information for each of the first RFID readers, generate a channel holding signal in each of the first frequency channels, and if a frequency channel usage request or a frequency channel return request is received from one of the first RFID readers, stop generating or generate the channel holding signal in a frequency channel related to the frequency channel usage or return request. In this manner, the collision between each of the RFID readers is avoided by preventing the second RFID readers from using the first frequency channels for the first RFID readers. Also, the method and the apparatus can efficiently manage frequency channels by controlling a ratio of the number of the first frequency channels to be used by the first RFID readers and the number of the second frequency channels to be used by the second RFID readers, according to usage frequency.
摘要:
Provided is an automatic vending system using RFID technology including a multi-tag unit including a plurality of RFID tags which store product sales information; and a sales management unit which receives a message of purchase request including information on a purchase requested product, checks if the purchase requested product is in stock based on the product sales information which is stored in the RFID tags, and sells the product if it is in stock.
摘要:
Provided is a method of transmitting/receiving data in a sensor node for reducing overhearing of sensor nodes, and a sensor network which implements the method. A sender node having transmission data from among a plurality of nodes which perform a low power listening (LPL) operation in an asynchronous manner at predetermined time intervals, generates a long preamble including short preambles, each having information including a destination address of the transmission data, a remainder of the long preamble, and a length of the transmission data, and sequentially transmits the second preamble and the transmission data. A receiver node from among the plurality of nodes determines whether a valid signal is sensed during an active state in the LPL operation. If it is determined that the valid signal is sensed, the receiver node receives the short preamble transmitted from the sender node. The receiver node determines a duration time of a deactivated state of the receiver node based on the received first preamble, thereby reducing overhearing in the sensor network.
摘要:
Provided are an antenna apparatus for linearly polarized diversity antennas in a radio frequency identification (RFID) reader, and a method of controlling the antenna apparatus. The antenna apparatus includes: a plurality of linearly polarized diversity antennas disposed to have different directions to one another; a switching unit connecting the linearly polarized diversity antennas to the RFID reader; and a controller controlling the switching unit to selectively activate the linearly polarized diversity antennas.
摘要:
Provided is a method and system for hierarchically communicating information between a user and an information providing server that provides information requested by the user. The system includes at least one sensor node, upon receipt of an information request message sent by the user through a terminal, searching for information corresponding to the information request message in a first cache mounted therein and sending the information request message if the corresponding information is not found in the first cache, and a cache server, upon receipt of the information request message from the at least one sensor node, searching for the information corresponding to the information request message in a second cache mounted therein, sending the information request message to the information providing server if the corresponding information is not found in the second cache, receiving the corresponding information, transmitting the received information to the sensor node, and updating the second cache.
摘要:
Provided is an apparatus for measuring a read range between a tag and a reader, which includes an electromagnetic anechoic chamber formed by connecting at least one unit cell in a row, the unit cell having an electromagnetic wave absorbent provided on an inner wall of each unit cell, an electromagnetic generation portion located at the unit cell at an end of the electromagnetic anechoic chamber and transmitting an electromagnetic wave through an antenna, and an electromagnetic measurement portion which measures a field strength of the electromagnetic wave transmitted from the electromagnetic generation portion using an electric field probe moving in the electromagnetic anechoic chamber.
摘要:
Provided are a radio frequency identification (RFID) tag and a wake-up method thereof. The RFID tag includes: a power source that supplies a driving voltage; a continuous wave detector that receives the driving voltage from the power supply so as to detect a continuous wave in a signal received from an RFID tag reader; a command detector that selectively receives the driving voltage and detects a command in the signal; and a controller that executes the command detected by the command detector by supplying the driving voltage to the command detector if the continuous wave is detected, and stops the driving voltage from being supplied to the command detector if no command is received from the command detector for a predetermined time period.