Abstract: Disclosed are channel management methods in a multicarrier structure in a mobile communication system. Uplink (UL) and downlink (DL) channel management methods in a carrier aggregation environment are used as the channel management methods. In DL, a base station determines a component carrier (CC) of an unstable radio channel state, stops data retransmission by the CC, and notifies a terminal of retransmission stop. In UL, the base station determines a CC of an unstable radio channel state and instructs the terminal to stop data retransmission by the CC, and the terminal stops the data retransmission and initializes a retransmission buffer.

Abstract: Provided are a receiving apparatus for a multiple input multiple output (MIMO) system and a method thereof. The receiving apparatus includes a QR decomposing unit for calculating a single (Q) matrix vector and an upper triangle (R) matrix vector for a receiving signal vector; a first symbol estimation unit for estimating predetermined symbols using the calculated Q matrix vector and R matrix vector; a log likelihood ratio (LLR) calculating unit for calculating log likelihood ratios of unit bits for the estimated symbols; an interference removing unit for receiving a decoded signal that is decided using the calculated log likelihood ratios and removing interference from the receiving signal vector; and a second symbol estimation unit for linearly estimating remaining symbols for the interference removed signal.

Abstract: The present invention provides an OFDM symbol generating apparatus. The OFDM symbol generating apparatus generates a plurality of weight-applied symbol groups by applying a plurality of weights to a digital modulation symbol group, and generates a plurality of IFFT symbol groups by performing an IFFT operation on the plurality of weight-applied symbol groups. Subsequently, an IFFT symbol group having the minimum PAPR is selected from among the plurality of IFFT symbol groups such that a characteristic of a PAPR can be improved without reducing data transmission speed.

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 effectively using power resource in a wireless mesh network is disclosed to select and change a level of a power saving mode according to terminal and network situations to increase the duration of the network's existence as well as improve the power consumption of each mesh terminal. After active mesh terminals that are to perform a data relay function and super-saving mesh terminals that are not to perform the data relay function are selected in consideration of a network topology at certain periods, the level of a power saving mode of the mesh terminals selected as the super-saving mesh terminals is higher than that of the mesh terminals selected as the active mesh terminals. And then, a routing path in a tree form is formed along the mesh terminals selected as the active mesh terminals to transmit data.

Abstract: Provided is a method of supporting node portability in a sensor network, wherein data transmission to a portable node can be guaranteed since even when the portable node is assigned with a different address by being associated with another network, the newly assigned address is transmitted to a parent node or a sink node that was previously associated with the portable node.

Abstract: A distributed resources sharing method using weighting factors of sub-domains in an optical network includes connecting working paths to an optical network according to a request of a subscriber, and calculating weighting factors for measurement of concentration of the sub-domains including the working paths by using information on connected working paths. The method also includes setting up the backup paths by using the weighting factors, and allocating resources in response to connection request at the time of setting up the backup path and sharing the allocated resources. With this method, it is possible to prevent a waste of idle resources caused from concentration of allocated resources. In addition, since the information of the idle resources in the network can be sensed at the time of selecting the backup paths by using a weight factor, the shared resources can be distributed, thereby maximizing efficiency of the resources.

Abstract: An apparatus for managing a plurality of wireless sensor networks selects a configuring policy according to a characteristic of each wireless sensor network and configures a network with the selected configuring policy for management. When an error occurs in the wireless sensor network, the apparatus performs error diagnosis based on a configuring policy applied to the error-detected wireless sensor network, infers a cause of the error, and provides an error recovery method corresponding to the inferred cause of the error to the error-detected wireless sensor network.

Abstract: The present invention relates to a signal converting device and receiving device in a wireless communication system. The receiving device of the wireless communication system includes a differential signal converter for receiving a single ended radio frequency signal and converting it into a differential radio frequency signal, and a frequency down converter for down converting the differential radio frequency signal to down frequency signal.

Abstract: Provided is a method of minimizing power consumed by each node in a wireless network when communicating with neighboring nodes. Unlike a conventional synchronous media access control (MAC), the present invention suggests an asynchronous MAC. Thus, the active duration of a node extends only when transmitting a large quantity of data and the extended active duration returns to the minimum active duration again after completing the data transmission.

Abstract: In a method of registering with an access point in a terminal of a wireless communication system, a frame includes a downlink sub-frame including a broadcast interval and a first management connection interval, and an uplink sub-frame including an access interval and a second management connection interval, the broadcast interval being used for transmitting a map message, the method includes: sending a first ranging request message to the access point using the access interval; receiving allocation information of a ranging slot from the access point using the map message; performing ranging through the ranging slot; sending a registration request message to the access point using the second management connection interval; and receiving information on whether to permit the registering from the access point using the first management connection interval.

Abstract: The MAC frame in a wireless communication system includes a terminal ID allocated to each of multiple terminals. At least one connection ID is allocated to each terminal having the terminal ID, and sub-carrier allocation information is allocated to each connection having the connection ID. The sub-carrier allocation information includes a sub-carrier allocation status for each sub-carrier, and the number of allocated information bits for each sub-carrier. The sub-carrier allocation status and the number of allocated information bits for each sub-carrier can be allocated, by sub-carriers, to the sub-carrier allocation information using a same number of bits; or the information on the sub-carrier allocation status is first allocated to the sub-carrier allocation information and the number of allocated information bits for each sub-carrier is allocated.

Abstract: In a cellular system in which OFDM is used, a forward link synchronization channel, a common pilot channel structure, an initial cell searching method of a mobile station, and an adjacent cell searching method for handover are required. A method of transmitting a forward synchronization signal in a wireless communication system according to the present invention includes generating a frame comprised of a plurality of sync blocks; and transmitting the frame through a forward link, wherein the frame comprises primary synchronization channel sequences which provide timing information of the sync blocks and a plurality of secondary synchronization channel sequences which provide timing information of the frame, wherein a cell identifier is specified by a combination of the primary synchronization channel sequence and a hopping code word specified by the plurality of the secondary synchronization channel sequences. Therefore, the cell searching time can be efficiently reduced in an OFDM system.

Abstract: A signal generation apparatus and signal receiving apparatus according to an Interleaved Frequency Division Multiple Access scheme is provided. The signal generation apparatus generates a plurality of complex symbols by digital-modulating a plurality of data symbols, and rotates the generated plurality of complex symbols in a plurality of each different phase angles. The signal generation apparatus generates a plurality of transmission symbols by repeating a plurality of rotated complex symbols at predetermined times, and rotating the repeatedly generated plurality of transmission chips in phase angles of an orthogonal phase sequence for the respective users. When the signal receiving apparatus receives the plurality of transmission symbols generated as described above, the maximum diversity gain may be obtained.

Abstract: Provided is a CMOS switch for use in RF switching having improved isolation properties. The CMOS switch includes a serial switching unit having first and second CMOS switches, a switching isolation unit for allowing an unselected output terminal of two output terminals to be electrically isolated from a common input terminal when the serial switching unit operates and an isolation enhancement unit. The isolation enhancement unit is connected in parallel to the first and the second CMOS switches between the two output terminals forming a parallel resonance circuit together with a parasitic capacitor of the serial switching unit. The CMOS switch for use in RF switching according to the present invention has a simple circuit structure and excellent operating properties at the MF or higher band. Also, the CMOS switch having high isolation properties is realized.

Abstract: Provided is an optical device having an edge effect with improved phase shift and propagation loss of light without decreasing the dynamic characteristics of the optical device. The optical device includes a first semiconductor layer which is doped with a first type of conductive impurities, and has a recessed groove in an upper portion thereof; a gate insulating layer covering the groove and a portion of the first semiconductor layer; and a second semiconductor layer which covers an upper surface of the gate insulating layer and is doped with a second type of conductive impurities opposite to the first type of conductive impurities.

Abstract: Provided are an apparatus and method for writing data to a phase-change random access memory (PRAM) by using writing power calculation and data inversion functions, and more particularly, an apparatus and method for writing data which can minimize power consumption by calculating the power consumed while input original data or inverted data is written to a PRAM and storing the data consuming less power. A PRAM consumes a significant amount of power in order to store data in a memory cell since a large electric current is required to flow for a long period of time.

Abstract: A method and apparatus for controlling a wavelength tuning of an optical source in an optical communication system. An operating temperature of an optical source is controlled and monitored to shorten a wavelength tuning time of the optical source generated in an optical source generator. When the current operating temperature reaches a final target temperature, an operating current is supplied to the optical source generator, and transmission of the operating current to the optical source generator is controlled and monitored. When the operating current reaches a final operating current, the wavelength tuning of the optical source is terminated. The operating temperature is adjusted by distinguishing between a smaller amount of temperature change and a larger amount of temperature change to prevent oscillation at the point of reaching the final target temperature, thereby minimizing the time taken for the output wavelength tuning.

Abstract: A system and a method for providing a secured transmission through an authenticated encryption for each ONU in downlink transmission of an OLT in GPON are provided. The GPON system includes an OLT for generating a GTC downlink frame by receiving data from an external service provider and ONUs for receiving the GTC downlink frame from the OLT and processing the received GTC downlink frame. The OLT performs the authenticated encryption for the generated GTC downlink frame according to the ONU by including an authentication generator and the ONU determines whether the GTC downlink frame is allowed to be processed or not by checking the authentication of the received GTC downlink frame through an authentication checker.

Abstract: Disclosed is a method for allocating data and pilots, a transmitting method and device, a receiving method and device in an OFDMA system. A terminal partitions subcarrier groups and symbols from an uplink channel based on a basic pilot pattern generated by a specific reference, receives at least one subchannel based on the partitioned subcarrier groups and symbols, hops the subcarrier groups caused by the subchannel according to hopping patterns, allocates data, and differently positions the pilots per subcarrier group based on the basic pilot pattern. Accordingly, the probability of pilot collision between adjacent cells is reduced, and accuracy of channel estimation is increased through boosting the pilot subcarrier power.