Abstract: A receiving apparatus for an RFID reader estimates channel coefficients for each of a plurality of receiving antennas based on tag response signals received via a plurality of receiving antennas, compensates the tag response signals received via the plurality of receiving antennas based on the channel coefficients estimated for each of a plurality of channel estimators, combines the compensated tag response signals for each of the plurality of receiving antennas to generate a combined signal, and detect bits in the combined signal.

Abstract: A Radio Frequency Identification (RFID) tag and an interrogator that support a normal mode and a secure mode, and operating methods thereof are provided. The RFID tag may notify the interrogator of whether a current operating mode of the RFID tag is the normal mode or the secure mode, may perform different inventory processes based on the current operating mode, and may perform an authentication of the interrogator. Here, the RFID tag and the interrogator may also perform a mutual authentication.

Abstract: Provided is a small switchable directional control antenna that can perform direction control according to shapes and sizes of various devices. The antenna includes a dielectric layer, a radiation patch formed on a side of the dielectric layer, a ground plane formed on a side of the dielectric layer opposite to the side on which the radiation patch is formed and configured to have a plurality of slots formed at edges thereof, and a control module insulated from the ground plane and configured to control electrical connection between the radiation patch and the ground plane.

Abstract: The loop antenna includes a loop coil connected to an RF signal source of a reader through a feed cable, and a switch that is turned on and off depending on a DC voltage that is proportional to the magnitude of an RF signal supplied from the RF signal source of the reader and opens the loop coil when turned off and closes the loop coil when turned on.

Abstract: A reader antenna includes dipole antennas, the dipole antennas including: a horizontal dipole antenna having the characteristic of horizontal polarization; and a dipole antenna perpendicular to the horizontal dipole antenna and including a vertical dipole antenna having the characteristic of vertical polarization, wherein the horizontal dipole antenna and the vertical dipole antenna may both have the characteristic of circular polarization. The reader antenna can be easily stored in an electronic shelf because it is realized in an ultrathin structure using a single-layered dielectric substrate.

Abstract: A receiving apparatus for an RFID reader estimates channel coefficients for each of a plurality of receiving antennas based on tag response signals received via a plurality of receiving antennas, compensates the tag response signals received via the plurality of receiving antennas based on the channel coefficients estimated for each of a plurality of channel estimators, combines the compensated tag response signals for each of the plurality of receiving antennas to generate a combined signal, and detect bits in the combined signal.

Abstract: In integrated circuit chips that are used for RFID, a method of calibrating an operation frequency that is generated in an operation frequency generator and a semiconductor wafer including a calibration circuit are provided. The method of calibrating an operation frequency of integrated circuit chips includes: supplying DC power to the integrated circuit chips; selecting an integrated circuit chip to perform calibration of an operation frequency; receiving an operation frequency that is generated in the selected integrated circuit chip; calculating a difference between a phase of the operation frequency and a phase of a calibration target frequency; generating a frequency calibration value of the operation frequency using the phase difference; transmitting a control signal including the frequency calibration value to the integrated circuit chip; and releasing a selection of the integrated circuit chip in which calibration of the operation frequency is complete.

Abstract: An IP packet forwarding server forwards an IP data packet between a user terminal and a machine-type communications (MTC) device allocated with a private internet protocol (IP). Such an IP packet forwarding server allocates a call identifier for connection between the user terminal and the MTC device, sets up a packet call to the MTC device and the user terminal using the call identifier, obtains packet forwarding information while setting up the packet call to the MTC device and the user terminal, and forwards an IP data packet between the MTC device and the user terminal using the packet forwarding information.

Abstract: Disclosed herein are a radio frequency identification (RFID) system and an operating method thereof. The RFID system includes an RFID tag and an RFID reader transmitting an initialization command to the RFID tag. The initialization command includes a field selecting a single tag accessing mode and a multi-tag processing mode. The RFID reader performs a single tag authentication procedure, which is a procedure of one-to-one accessing one RFID tag, in the case in which the field is set to the single tag accessing mode.

Abstract: Disclosed herein are a tag transmission apparatus and a signal transmitting method thereof. The tag transmission apparatus converts a plurality of data bits into a symbol, which is one of a plurality of symbols, and multiplies the converted symbol by a square-wave having a predetermined frequency to thereby generate a subcarrier signal. Here, in the case in which the plurality of data bits are n (n is a natural number larger than 2) bits, the number of the plurality of symbols is 2n.

Abstract: An apparatus for managing a channel resource by a node sets a channel hopping sequence and a channel hopping offset value which are to be used, divides an assigned time slot into a plurality of subslots, divides a data frame for transmission into a plurality of subframes, and selects a channel for transmitting the plurality of subframes in the plurality of subslots, respectively, by channel hopping based on the channel hopping sequence, the channel hopping offset value, the index of the time slot, and the index of a subslot for transmitting a subframe.

Abstract: A total history management system using a radio frequency identification (RFID) tag and a barcode. The system includes an RFID tag, a barcode recorder and a barcode reader. The RFID tag is attached to a box containing a plurality of individual products to store an environmental history of a distribution. The barcode recorder is configured to provide, to each of the plurality of individual products, a barcode in which identification (ID) information of the RFID tag is recorded. The barcode reader is configured to recognize the barcode attached to each of the plurality of individual products, and to output the environmental history of the distribution, corresponding to the ID information of the RFID tag that is received in response to a query with respect to the RFID tag, using the recognized barcode.

Abstract: In a wireless sensor network, it is determined whether to multiplex a packet that is generated in a random node. When a packet is to be multiplexed, by multiplexing at least one packet, a frame of a first length is generated and transmitted. The frame of the first length includes a payload in which at least one of data portions including a header unit and a data unit having a second length smaller than the first length is multiplexed.

Abstract: A multi-channel wireless network acquires reference time information that is commonly applied to all multi-channels and acquires packet receiving time information of a received packet on each channel basis based on the reference time information by spreading and applying the reference time information to each channel.

Abstract: A method and apparatus having advantages of resolving a phenomenon in which traffic is concentrated on an AP of a wireless network and preventing traffic collision to enhance network efficiency are provided. Thousands or more of nodes included in a wireless network can be connected to the wireless network through a plurality of distributed association nodes, rather than through a single AP, and thus, concentration can be resolved and the wireless network can be effectively operated. Also, by performing distributed association on the basis of a single hop, implementation complexity can be lowered.

Abstract: Disclosed are methods for service discovery in a wireless personal area communication network. A method for service discovery, performed in a terminal, the method comprises performing a passive scan for searching a specific service based on whether to receive a frame including a specific service identifier; and, when it fails to search the specific service, performing an active scan which broadcasts a service discovery request command frame for searching the specific service. Thus, service discovery may be efficiently performed by reducing the operation complexity of the terminal and minimizing the power consumption of the terminal needed for service discovery, without support of a upper layer.

Abstract: A tag transmitting apparatus of a passive RFID (radio frequency identification) system generates a pilot tone, a preamble, and an SFD (start frame delimiter) and transmits the pilot, the preamble, and the SFD, using one of a plurality of square waves.

Abstract: According to an exemplary embodiment of the present invention, a method for time synchronization of a first node in a peer aware communication (PAC) environment is provided. The first node obtains medium access control authority by performing contention with a second node neighboring the first node. The first node adds a time synchronization offset to the first beacon frame. In addition, the first node transmits the first beacon frame in a beacon period of a superframe when obtaining the media access control authority.

Abstract: An RFID system using an M pulse amplitude modulation (M-PAM) or M quadrature amplitude modulation (M-QAM) scheme using a plurality of load-modulators, a plurality of antennas, and a communication method thereof are provided. The RFID system includes: an RFID tag; and a reader device communicating with the RFID device, wherein the RFID tag includes: N load-modulators an N antennas communicating with the reader device in any one scheme of M-pulse amplitude modulation (M-PAM) and M-quadrature amplitude modulation (M-QAM) in which modulation of an M level is performed and operated corresponding to the M level.

Abstract: A received signal strength indicator is provided. The received signal strength indicator includes a plurality of differential amplifiers forming an amplifier chain for amplifying differential signals and a plurality of rectifiers for rectifying signals output from the plurality of differential amplifiers and the differential signals, and a low pass filter for combining the signals rectified by the plurality of rectifiers to output received signal strength. Each rectifier includes a class AB voltage-current converter for converting a differential voltage into a current, and two triode transistors.