Abstract: Proposed is a precursor composition for forming a metal film including a zirconium compound represented by any one of Chemical Formulas 1 to 3 and a hafnium compound represented by any one of Chemical Formulas 4 to 6.

Abstract: Proposed is a heat dissipating device using turbulent flow. In the heat dissipating device, a plurality of block flow paths are formed in parallel inside a block body, a first cap and a second cap are mounted on side surfaces of the respective ends of the block body so as to connect the block flow paths, a working fluid flows into the block flow paths, and the working fluid which has passed through the block flow paths is transferred to the outside. Turbulence generators are mounted inside the block flow paths, and finishing end portions on the respective ends of the turbulence generators are supported by the first cap and the second cap and are positioned inside the block flow paths.

Abstract: Provided is a method of generating a pilot pattern capable of perform adaptive channel estimation, and a method and apparatus of a base station and a method and apparatus of a terminal using the pilot pattern. The pilot pattern selects pilot symbol positions based on distances from pilots of previous orthogonal frequency division multiple access (OFDMA) symbols to a subcarrier position of a current OFDMA symbol in the frequency domain and the time domain, so that a low pilot density is maintained so as to effectively transmit data, and stable channel estimation performance can be obtained even in a bad channel environment. In addition, the minimum burst allocation size is determined according to the channel environment between the base station and the terminal, guaranteeing channel estimation performance suitable for the channel environment, and improving granularity, channel estimation latency, and channel estimation memory size.

Abstract: The present invention provides a method and system for performing distributed channel sensing in which channel information is collected by performing channel sensing according to a channel sensing priority which is determined according to a relative position of a cell to which a wireless connection device belongs from among a plurality of cells which logically partition the zone of the wireless network, and thus the overhead of the channel sensing which is generated in a cognitive wireless multi-hop network environment is reduced, and the transmission failure which occurs when the wireless connection device detects frequencies is reduced.

Abstract: A method of assigning a frequency channel using efficient spectrum sensing in a multiple Frequency Assignment system includes a channel sensing process, wherein a base station of a secondary user classifies multiple frequency channels licensed to a primary user into a plurality of channel state sets according to usage states, periodically senses channel states by changing a sensing period according to the types of classified channel state sets, and manages the sensed channel states as frequency channel state set information; a channel state set broadcasting process; and a channel assigning process. Accordingly, a frequency channel can be assigned to a secondary user requesting channel assignment using frequency channel state set information without a primary user experiencing interference noise.

Abstract: A method provides an identifying OFDM communication signal using OFDM symbol estimation. In view of the above, the present invention provides an apparatus and method for identifying an OFDM communication signal using an OFDM symbol estimation, which is capable of analyzing the OFDM signal with a high accuracy in a cognitive radio technique, thereby identifying the OFDM signal from a heterogeneous communication signal.

Abstract: A method and an apparatus for controlling transmit power of a CR device are provided. The method includes acquiring CR environment information regarding a licensed user or an unlicensed user occupying an adjacent channel or an adjacent cell of the CR device; determining a transmit power value of the CR device using the CR environment information; and generating transmit power control information including the transmit power value. The method and apparatus guarantee reliable communication of the CR device and minimize interference with the licensed user.

Abstract: Provided is an apparatus for controlling subcarrier spacing in a system supporting multiple frequency bands. The apparatus for controlling a subcarrier spacing comprises: an interference detection unit detecting interference over multiple frequency bands; a system parameter provision unit providing system parameters related to a subcarrier spacing between the multiple frequency bands—for example RF, FFT size, and channel bandwidth; a subcarrier spacing control unit controlling the subcarrier spacing such that the detected interference is reduced, on the basis of the system parameters. In a system operating with multiple bands, different subcarrier spacing can be applied by each band, thereby controlling interference occurring in each band.

Abstract: The present invention provides a method and system for performing distributed channel sensing in which channel information is collected by performing channel sensing according to a channel sensing priority which is determined according to a relative position of a cell to which a wireless connection device belongs from among a plurality of cells which logically partition the zone of the wireless network, and thus the overhead of the channel sensing which is generated in a cognitive wireless multi-hop network environment is reduced, and the transmission failure which occurs when the wireless connection device detects frequencies is reduced.

Abstract: A method and apparatus of an effective and reliable retransmission based on soft combining when using orthogonal frequency division multiplexing (OFDM) modulation technique in a contention based access system. The method includes receiving a data signal from a transmission node, performing soft combining the valid section part of the data signal which have been previously received and the data signal currently received, determining a collision section of the data signal which is currently received, and saving a valid section part except the collision section of the data signal which is currently received in a buffer. In the contention based access system that uses OFDM modulation technique, in case that data signal reception failure occurs due to a transmission collision, the valid part of the received data signal may be detected and effectively applied to the soft combining, and consequently, the reception probability of data signal can be increased.

Abstract: A communication method of a transmitter using a preamble in a wireless communication system, includes determining at least two subcarriers from among a plurality of subcarriers, for the preamble; mapping a subcarrier sequence and a subcarrier phase value of the preamble to the at least two subcarriers; and transmitting the preamble using the at least two subcarriers. The preamble may include a real component having a first repeated pattern in a preset time interval, and an imaginary component having a second repeated pattern in the preset time interval, and a relationship between the first repeated pattern and the second repeated pattern may indicate characteristic information of the wireless communication system.

Abstract: A radio access method for use in a radio access device in cognitive radio ad-hoc networks, the radio access method comprising: comparing additional information about neighboring radio access devices, which exist in the cognitive radio ad-hoc networks, in a second layer of the radio access device with additional information about the neighboring radio access devices in a third layer of the radio access device in the cognitive radio ad-hoc networks; and generating a routing control message when the additional information of the second layer is different from the additional information of the third layer to broadcast the routing control message.

Abstract: A wireless communication system provides a method and device for transmitting a preamble. A transmitter generates a first preamble sequence used for frequency offset estimation and generates a second preamble sequence according to the transmission mode. The transmitter transmits the first and second preamble sequences. With respect to the second preamble sequence, the phase thereof may be shifted into different phase offsets according to the transmission mode.

Abstract: Provided is a hybrid beaconing method in which a centralized beaconing scheme and a distributed beaconing scheme are combined. In the hybrid beaconing method, a beaconing scheme is converted according to a network condition, and a centralized beaconing scheme or a distributed beaconing scheme is used to maintain an optimum network status.

Abstract: Provided is a method of generating a pilot pattern capable of perform adaptive channel estimation, and a method and apparatus of a base station and a method and apparatus of a terminal using the pilot pattern. The pilot pattern selects pilot symbol positions based on distances from pilots of previous orthogonal frequency division multiple access (OFDMA) symbols to a subcarrier position of a current OFDMA symbol in the frequency domain and the time domain, so that a low pilot density is maintained so as to effectively transmit data, and stable channel estimation performance can be obtained even in a bad channel environment. In addition, the minimum burst allocation size is determined according to the channel environment between the base station and the terminal, guaranteeing channel estimation performance suitable for the channel environment, and improving granularity, channel estimation latency, and channel estimation memory size.

Abstract: A method for dynamically managing channels in a DSA radio system that supports multiple channels, includes producing a number of rendezvous combinations by pairing operating channels and backup channels in an 1:1 relation based on an available channel list. Further, the method includes when an arbitrary operating channel in a rendezvous combination is not suitable for communications, extracting a backup channel from the rendezvous combination to which the arbitrary operating channel belongs; and switching the extracted backup channel as an operating channel to continue a communication.

Abstract: The present invention relates to a method for reducing an average time period adopted at the time of evaluating an effect of electromagnetic fields of a mobile communication base station near the mobile communication base station on a human body and measurement is performed for 6 minutes at a predetermined measurement point for acquiring a whole body average by comparing a site measurement result targeting multiple base stations and uncertainty by repetitive measurement and when a 6-minute average value and an average value for a reduced time period which is shorter than 6 minutes are compared with each other, a standard deviation is equal to or lower than a predetermined level, e.g., 0.4 dB, it is sufficient even by the measurement for the reduced time period which is shorter than 6 minutes.

Abstract: A method provides an identifying OFDM communication signal using OFDM symbol estimation. In view of the above, the present invention provides an apparatus and method for identifying an OFDM communication signal using an OFDM symbol estimation, which is capable of analyzing the OFDM signal with a high accuracy in a cognitive radio technique, thereby identifying the OFDM signal from a heterogeneous communication signal.

Abstract: Provided is a method of generating a pilot pattern capable of perform adaptive channel estimation, and a method and apparatus of a base station and a method and apparatus of a terminal using the pilot pattern. The pilot pattern selects pilot symbol positions based on distances from pilots of previous orthogonal frequency division multiple access (OFDMA) symbols to a subcarrier position of a current OFDMA symbol in the frequency domain and the time domain, so that a low pilot density is maintained so as to effectively transmit data, and stable channel estimation performance can be obtained even in a bad channel environment. In addition, the minimum burst allocation size is determined according to the channel environment between the base station and the terminal, guaranteeing channel estimation performance suitable for the channel environment, and improving granularity, channel estimation latency, and channel estimation memory size.

Abstract: Provided is a method of generating a pilot pattern capable of perform adaptive channel estimation, and a method and apparatus of a base station and a method and apparatus of a terminal using the pilot pattern. The pilot pattern selects pilot symbol positions based on distances from pilots of previous orthogonal frequency division multiple access (OFDMA) symbols to a subcarrier position of a current OFDMA symbol in the frequency domain and the time domain, so that a low pilot density is maintained so as to effectively transmit data, and stable channel estimation performance can be obtained even in a bad channel environment. In addition, the minimum burst allocation size is determined according to the channel environment between the base station and the terminal, guaranteeing channel estimation performance suitable for the channel environment, and improving granularity, channel estimation latency, and channel estimation memory size.