Abstract: Provided are a network communication method and a network device using a preamble. According to the network communication method and the network device, network coexistence is easily achieved by using network identification transmitted in the preamble, and an unknown terminal, which has a low reception signal to noise ratio (SNR) and has not yet been connected to an existing network, is easily connected to the existing network.

Abstract: There is an apparatus for predicting wave propagation characteristic of a multiple antenna system, including: a transmission position calculator for calculating transmission positions of multiple transmitting antennas; a wave propagation path searcher for searching for a wave propagation path for each of a plurality of image antennas generated for each of said multiple transmitting antennas; a reflection electric field calculator for calculating a partial reflection electric field on the searched propagation path; and a received power calculator for calculating a received power based on the calculated partial reflection electric field.

Abstract: A method and apparatus for modeling radio propagation is provided. In the method, when a wall having a thickness is modeled as a line having no thickness, an error in a shade area is minimized by considering the thickness of a wall while maintaining simplicity in a ray-tracing method.

Abstract: A double-ridged horn antenna having a higher-order mode suppressor includes a pair of upper and lower ridges arranged opposite to each other, each of the upper and lower ridges having an inner surface to guide electromagnetic waves and an outer surface arranged opposite to the inner surface; upper and lower flares fixedly attached to respective outer surfaces of the upper and lower ridges; left and right flares coupled to the upper and lower flares to form a rectangular cone structure; and metal conductors symmetrically positioned between the upper and lower ridges and the left and right flares.

Abstract: The present invention relates to an apparatus and method for receiving an antenna measuring signal, and a system of measuring an antenna. In particular, the present invention relates to an apparatus and method for receiving an antenna measuring signal that can remove a measurement error caused by motion of an antenna cable, and a system for measuring an antenna. According to the apparatus and method for receiving an antenna measuring signal and the system and method for measuring an antenna according to the present invention, it is possible to remove a coupling effect of an RF cable of a receiving antenna side while measuring antenna characteristics, thereby minimizing a measurement error of the antenna.

Abstract: An antenna radiation pattern measurement device that measures a radiation pattern of an AUT by using a source antenna includes a control unit, an analysis unit, and a measurement unit. The control unit controls driving of the source antenna and the AUT. The analysis unit measures an electric field value from a radio frequency (RF) signal that is transmitted from one of the source antenna and the AUT and received by the other antenna. In addition, the measurement unit controls the control unit and the analysis unit and measures a radiation pattern of the AUT by using the electric field value.

Abstract: Provided are a method of adaptively allocating appropriate hybrid bursts according to terminal attributes including terminal position, channel state, and service type in an orthogonal frequency-division multi-access (OFDMA) system, and an upstream-MAP information element (US-MAP IE) structure supporting the method. The method includes dividing an upstream subframe into a plurality of zones depending on the number of OFDMA symbols and allocating bursts of a zone to a terminal according to the terminal attributes. Bursts are formed by allocating slots along a time axis in the upstream subframe, and are formed by allocating slots along a frequency axis in a downstream subframe.

Abstract: A method and apparatus for detecting a signal using a cyclo-stationary characteristic value is provided. A method of detecting a signal using a cyclo-stationary characteristic value includes: calculating cyclo-stationary characteristic values with respect to a cyclic frequency domain of an input signal; multiplying the calculated cyclo-stationary characteristic values with each other; and detecting the signal from the input signal based on the result of the multiplication.

Abstract: There is provided a comb polarizer suitable for millimeter band applications including: a waveguide having an aperture side formed of two separable half waveguides, and a comb shaped conductive unit having a plurality of cogs interposed between two half waveguides for transforming a linear polarized signal to a circular polarized signal.

Abstract: There is a provided a method for managing a multiple frequency assignment using a terminal's RX performance in an orthogonal frequency division multiple access (OFDMA) wireless regional area network (WRAN) system, including: a) measuring a bit energy/noise power spectral density (Eb/No) and a received signal strength indicator (RSSI) which are received in the terminal; b) informing the measured Eb/No and RSSI of a base station; c) calculating a round trip delay (RTD) in the base station; d) determining a terminal performance level based on the measured Eb/No, RSSI and the calculated RTD; and e) determining a frequency channel and modulation scheme based on the determined performance level.

Abstract: A resource allocation method for an orthogonal frequency division multiplexing access (OFDMA) system is provided. The resource allocation method includes dividing a frequency band occupied by a predetermined number of OFDM symbols into a plurality of subbands and determining the number of diversity subchannels, each of which comprises at least two time-frequency resources respectively included in different subbands, and the number of subband selective subchannels, which comprise time-frequency resources that are not included in the diversity subchannels; and generating the diversity subchannels and the subband selective subchannels according to the determined numbers and allocating a physical channel comprised of a generated subchannel to a user in a cell. Accordingly, diversity is enhanced without reducing the freedom of selection of a subband.

Abstract: An electromagnetic-wave suppression structure in a multilayer PCB or package structure is supplied with a power to be used therein by a power distribution network including a power plane and a ground plane. The multilayer PCB and package includes: an electromagnetic-wave suppression structure including an electromagnetic band-gap; and the electromagnetic-wave suppression structure is formed at a specific portion(s) of the power plane and/or the ground plane to suppress noises.

Abstract: An electromagnetic absorber using resistive material includes a ground plane of a conductive material; a dielectric layer formed on the ground plane; and a pattern layer in which specific unit cell patterns made of a resistive material are periodically arranged on the dielectric layer. The electromagnetic absorber is applied to an electronic toll collection system, a transportation device, a building structure, an electronic device and an anechoic chamber.

Abstract: A probe and an antenna reduces the multiple reflection of electromagnetic waves. The probe includes: a waveguide; and a resonance unit entirely or partially disposed in the inside of the waveguide and comprising a conductor.

Abstract: Provided is a method and apparatus of generating signals for initial ranging in an Orthogonal Frequency Division Multiple Access (OFDMA) system. The method, includes: generating a plurality of ranging symbols by cyclic-shifting sample data of a ranging symbol in one OFDMA symbol period as much as a value obtained by multiplying a cyclic prefix size by a symbol index; generating a ranging signal by copying a rear part corresponding to the cyclic prefix size in the sample data with respect to each of the ranging symbols and inserting the copied rear part in front of the sample data as a cyclic prefix.

Abstract: Provided is a shaped-beam antenna having a multi-layered conductive element array surrounded by a dielectric ring. The shaped-beam antenna includes: a planar excitation element having a radiation structure according to a required polarization; a multi-layered conductive element array disposed on the planer excitation element, wherein the multi-layered conductive element array is formed by layering conductive elements at an arbitrary interval; and a dielectric ring surrounding the multi-layered conductive element array at a predetermined separation distance therefrom. Accordingly, it is possible to reduce the entire size of the shaped-beam antenna and manufacturing costs thereof.

Abstract: Provided are an antenna radiation performance measuring apparatus and a method for designing the same. The apparatus includes a chamber configured to include a transmit antenna radiating electromagnetic wave, a receive antenna receiving the electromagnetic wave, and an electromagnetic wave absorber absorbing the electromagnetic wave, and a reflector disposed on one side of the chamber between the transmit antenna and the receive antenna, inclined at a predetermined angle, and configured to reflect an electromagnetic wave radiated in a direction to the one side from the transmit antenna.

Abstract: The present invention relates to relay customer premises equipment (RCPE) for exchanging operational information and coexistence information of each cell between adjacent cells in a cellular system. The present invention enables effective control between multiple cells by directly transmitting operational information and coexistence information between cells over air links.

Abstract: Provided are a transceiver and a transceiving method for use in an ultra wide band system for frequency sharing. The transceiver for use in an ultra wide band system for reducing interference that can be generated by an external system includes an external signal detector which detects an external signal generated from the external system, and a transmission signal controller which determines a power level of a transmission signal to be transmitted by the transceiver based on a power level of the detected external signal, in the case where an external signal using the same frequency channel as the ultra band system is detected, wherein the ultra wide band system and the external system are in a frequency sharing environment.

Abstract: There is provided to a method for measuring antenna characteristics operating in an out-of-operational frequency range of a chamber, in the chamber having a predetermined operational frequency range, including the steps of: a) measuring reflected wave characteristics of the out-of-operational frequency range generated within the chamber; b) measuring the characteristics of a measurement target antenna operating in the out-of-operational frequency range of the chamber; and c) measuring final characteristics of the measurement target antenna by compensating the characteristic data of the measurement target antenna measured in the step b) for reflected wave data measured in the step a).