Abstract:
A cognitive radio apparatus according to an embodiment comprises an estimation module for generating a channel estimation signal transmitted to a random reception apparatus located in the random channel when the random channel is selected among multiple channels to execute communication in a cognitive radio network; a communication module for transmitting the channel estimation signal to the random reception apparatus and for receiving a channel response signal from the random reception apparatus; and a control module for controlling the communication module to transmit a communication signal set for the random channel or a variable communication signal for converting the communication signal to the random reception apparatus when a result on which the random channel is located in a deep fading section is determined based on the channel response signal.
Abstract:
The present invention provides an apparatus and a method for controlling transmission output of a wireless device that automatically controls transmission output of a wireless device using a TV band according to a frequency band. The present invention is configured to include a frequency band selection unit for selecting frequency bands to be compared; a radio wave decrement calculation unit for calculating a radio wave decrement for each of the selected frequency bands; and a transmission output control unit for automatically controlling the transmission output of the wireless device using the TV band based on a difference value between the calculated radio wave decrements. According to the present invention, a service area can be widened while sufficiently protecting a service provided in the TV band, and frequency resources can be used efficiently.
Abstract:
PURPOSE: A wideband transmitting/receiving device for a multiband is provided to obtain excellent channel-to-ratios in all channels. CONSTITUTION: A wideband transmitting/receiving device for a multiband includes a local oscillator (210), a level detector (260), an analog/digital (A/D) converter (270), a controller (280), and a distributor (230). The local oscillator generates a local oscillation signal. The level detector measures the size of the local oscillation signal. The A/D converter converts the measured size of the local oscillation signal into a digital signal. The controller controls a variable amplifier (220) according to the measured size of the local oscillation signal. The distributor respectively applies the local oscillation signal of which the size is regularly maintained to the local oscillation (LO) inputs of frequency converters in a transmitting part and receiving part. [Reference numerals] (210) Local oscillator; (220) Variable amplifier; (230) Distributor; (241,242) Low pass filter; (251,252) Switch; (260) Level detector; (280) Controller; (AA) Transmitting LO; (BB) Receiving LO
Abstract:
PURPOSE: A device for reducing noise in a DC power supply is provided to prevent an error occurrence due to a spur component in a spectrum sensing receiver, and to improve a signal to noise ratio of a transceiver by removing a direct current noise of an SMPS(Switching Mode Power Supplier) by using a circuit for eliminating noise. CONSTITUTION: A device for reducing noise in DC power supply comprises a ferrit bead(41) removing after converting a noise included in a DC voltage inputted from an SMPS into heat; and a low frequency filter(43) removing a low frequency noise of the DC voltage by having an inductor and a capacitor.
Abstract:
PURPOSE: A communication device including a spectrum sensing antenna and a data transceiving antenna in a cognitive radio communication system and an antenna switching method in the communication device are provided to select an optimal antenna from antennas according to the quality of a currently performing channel. CONSTITUTION: A quality measuring unit(851) measures information related to the quality of a channel different from a channel between a communication device and another communication device based on data received from the communication device through a primary antenna or a secondary antenna. A determining unit(852) determines whether the channel has a better state than another channel based on the measured information. If the state of the channel is not better than another channel based on the determined result, a control unit(853) controls a switch to mutually change connection targets of the primary antenna and the secondary antenna. [Reference numerals] (810) Primary antenna; (820) Secondary antenna; (830) Data transceiver; (840) Spectrum generator; (850) Switching processor; (851) Quality measuring unit; (852) Determining unit; (853) Control unit;
Abstract:
본 발명은 단일 캐리어 주파수 분할 다중접속 방식을 이용하는 이동통신시스템에 다중안테나를 적용하는 기술에 관한 것이다. 본 발명은 변조된 심볼을 복수의 레이어에 맵핑하는 레이어 맵퍼, 상기 각 레이어에 맵핑된 심볼을 복수의 시간 영역 스트림에 균등하게 분할 혼합하는 레이어 쉬프터 및 상기 복수의 시간 영역 스트림을 각각 이산 푸리에 변환(DFT: Discrete Fourier Transform)변환하여 복수의 주파수 영역 스트림을 생성하고, 상기 각 주파수 영역 스트림에 상응하는 안테나를 이용하여 상기 주파수 영역 스트림을 수신 장치로 전송하는 신호 전송부 및 이에 상응하는 수신부를 포함하는 것을 특징으로 하는 전송 장치를 제공한다. 단일 캐리어 주파수 분할 다중 접속, SC-FDMA, OFDM, PAPR