Abstract: A multi-channel digital TV transmission system and method are provided. In the multi-channel digital TV transmission system and method, a single auxiliary transmitter may be configured to be switched with respect to a plurality of main transmitters and thus, it is possible to provide a broadcasting service without interruption even when an fault occurs in a main transmitter among the plurality of main transmitters, to reduce costs of a multi-channel digital TV transmission system, and to ensure a wide facility space.

Abstract: Provided are a terminal and a base station, and a frequency sensing method thereof. The terminal or the base station may filter a frequency band needing frequency sensing in the entire frequency band where the terminal or the base station may receive an input signal. It is possible to enhance a detection performance and rate of signals by applying frequency sensing to the filtered frequency band.

Abstract: A method for 3D preprocessing for ray tracing includes: selecting and storing visible surfaces by designating one of a plurality of structures as a reference structure and remaining structures as relative structures, searching for the relative structures from the reference structure, storing relative structures having a surface visible from the reference structure, and removing relative structures having an invisible surface; conducting selection and storage based on distance measurement by measuring the distance from the reference structure to each of the stored relative structures and removing relative structures positioned beyond a reference spot predetermined with reference to the reference structure; and calculating a ray propagation path by calculating the propagation path of the ray between the reference structure and each of the relative structures stored in said conducting selection and storage based on distance measurement.

Abstract: Provided is a method and apparatus for sharing a frequency in an environment where an incumbent system exists. In a frequency environment where the incumbent system exists, a frequency resource management may be smoothly performed using a plurality of frequency sets classified based on a utilization state of each sub-frequency resource. When a frequency sharing system using the same radio access technology (RAT) as a frequency sharing system to be assigned with a frequency resource exists, it is possible to reduce overhead for frequency sharing by priorly assigning a corresponding frequency resource to to the frequency sharing system to be assigned with the frequency resource.

Abstract: Disclosed is an apparatus and method for ray-tracing using a path preprocess. The method for ray-tracing including launching a ray from a transmitting point at angles with regular intervals, setting a first side of an object where the launched ray is projected as a reference patch, and searching predetermined preprocessed path data for a counterpart patch corresponding to a second side of another object, the second side being exposed to the projected ray reflected or diffracted from the set reference patch, and tracing a transmission path of the reflected or diffracted ray.

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 apparatus for evaluating interference of a cognitive radio transmission signal with digital TV broadcasting includes a cognitive radio transmission unit generating and transmitting an interference signal using orthogonal frequency division multiple access (OFDMA), a broadcast transmission unit generating and transmitting a baseband digital TV broadcast signal containing data about a program to be broadcast, and a broadcast receiving evaluation unit evaluating a signal interference on the digital TV broadcast signal due to the interference signal from a signal combining a broadcast signal that the broadcast transmission unit transmits and the interference signal that the cognitive radio transmission unit transmits, by the signal interference.

Abstract: An apparatus and method of determining a modification of a wireless service use for spectrum liberalization is provided. When a licensee using a wireless service in a particular band desires to modify the wireless service use, the method of determining a modification of a wireless service use for spectrum liberalization may determine whether to modify the wireless service use through a worst-case interference check scheme and a Monte-Carlo interference check scheme.

Abstract: A method of computing a probability of interference in an overlay system and an underlay system, the method including: setting an input parameter corresponding to each of an interfered receiver, an interfering transmitter, an opposing transmitter, and a target receiver; computing a strength of a received signal, received in the interfered receiver from the opposing transmitter; computing a transmission signal level from a victim link in the interfering transmitter; determining whether the interfering transmitter transmits a signal in the overlay system; determining a transmission power of the interfering transmitter based on the computed transmission signal level in the underlay system; computing a strength of an interference signal depending on whether the interfering transmitter transmits the signal and the transmission power of the interfering transmitter; and computing the probability of interference using the computed strength of the received signal and the computed strength of the interference signal.

Abstract: Disclosed is a binary phase shift key (BPSK) demodulating device using a phase shifter and a method thereof. The BPSK demodulating device includes an I signal generator to generate an in-phase (I) signal from a received BPSK signal, a Q signal generator to generate a quadrature-phase (Q) signal from the received BPSK signal, using a plurality of phase shifters, an oscillator to generate a first signal to separate a baseband signal, and a determining unit to determine a transmission phase angle based on the I signal and the Q signal.

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: Provided is a method for analyzing a reflection wave using effective impedance. The method includes the steps of: a) modeling a reflection surface of a building two-dimensionally; and b) obtaining a reflection wave by radiating a radio wave to the modeled reflection surface and analyzing the obtained reflection wave through making medium uniform.

Abstract: Provided are a method of adjusting a PCS threshold in a wireless network, and a terminal apparatus for the wireless network. The method and the apparatus determines whether to adjust the PCS threshold to use a shared channel for transmitting data in a wireless network based on a congestion status of the shared channel, and adjusts the PCS threshold based on a packet loss measured for a predetermined period of time.

Abstract: Provided are a packet transmission scheduling method in a wireless network and a packet transmission method using the same. The packet transmission scheduling method, includes storing location information and a path loss exponent of each node on a multiplexing path; calculating a Signal-to-Interference and Noise Ratio (SINR) between nodes on a predetermined path based on the stored location information; when the calculated SINR exceeds a threshold, forming the paths as a path table; and scheduling packet transmission based on the formed path table.

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: An intermodulation signal detector is implemented in a non-linear super high frequency circuit for stably detecting an intermodulation signal regardless of the variations of non-linear characteristics of the super high frequency element and an external environment by using combined two transmission lines on which signals have the same amplitude and 180° different phases.

Abstract: An intermodulation signal detector is implemented in a non-linear super high frequency circuit for stably detecting an intermodulation signal regardless of the variations of non-linear characteristics of the super high frequency element and an external environment by using combined two transmission lines on which signals have the same amplitude and 180° different phases.