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