Abstract: A wireless device of a communication system randomly selects a backoff counter at a contention window interval corresponding to a contention window size that is determined according to a backoff stage, attempts packet transmission, when the backoff counter becomes 0 while reducing the backoff counter, when a radio channel is in an idle status, and increases the contention window size while increasing the backoff stage by 1 according to a first predetermined condition. In this case, as the backoff stage increases, a contention window size has a concave down increasing form.

Abstract: Provided are a data frame structure of a wireless communication system, which follows a sharing protocol which may be operated to coexist with a system that operates in an unlicensed spectrum, such as a WiFi system, and the like in the wireless communication system using a licensed spectrum such as an LTE system and an operation method of the system, and a terminal and a device of a base station for the operation.

Abstract: Provided is a PIM detection apparatus including: a tone signal input unit configured to apply a tone signal having a first frequency characteristic to a test target apparatus; a sequence signal input unit configured to apply a sequence signal having a second frequency characteristic to the test target apparatus; a PIM detector configured to receive a Passive Intermodulation (PIM) signal from the test target apparatus, and to detect a delay time and a size of the PIM signal based on the sequence signal; and a PIM position determiner configured to determine a PIM occurrence position by using the delay time and the size of the PIM signal.

Abstract: An exemplary embodiment of the present information discloses a base station which transmits a discovery reference signal (DRS) in an unlicensed band, including: a transmission control unit which sets different timings to transmit the DRS for each of a plurality of channels; and a communication unit which transmits the DRS to the outside through the plurality of channels based on the set timing.

Abstract: A communication node configures an unlicensed band transmission burst including a plurality of subframes in consideration of an occupancy state of a channel of an unlicensed band and transmits the unlicensed band transmission burst through the unlicensed band. In this case, at least one subframe of the plurality of subframes has a different type from the remaining subframes.

Abstract: An operation method of a communication node supporting a licensed band and an unlicensed band is disclosed. As an exemplary embodiment according to the present disclosure, an operation method of a user equipment (UE) in a communication network may comprise measuring a received signal strength during a measurement period in an unlicensed band; determining a channel occupation status by comparing the measured received signal strength with a predetermined threshold; and reporting information indicating the channel occupation status to a base station. Therefore, performance of the communication network can be enhanced.

Abstract: Disclosed are operation methods of a communication node in a network supporting licensed and unlicensed bands. An operation method of a user equipment (UE) may comprises receiving, from a base station, a physical downlink control channel (PDCCH) including downlink control information (DCI) in a subframe n?1 of an unlicensed band; decoding the DCI using a common radio network temporary identifier (RNTI); and identifying the number of symbols of the subframe n?1 or a subframe n based on the decoded DCI. Therefore, a performance of the network can be enhanced.

Abstract: Disclosed is a scheduling method for a communication network supporting an unlicensed band. An operation method of a user equipment (UE) may comprise obtaining a control channel from a partial subframe having a length of less than 1 millisecond in an unlicensed band; obtaining scheduling information from the control channel; and obtaining a data channel indicated by the scheduling information from the partial subframe. Therefore, performance of the communication network can be enhanced.

Abstract: Provided herein is a method and apparatus for heterogeneous carrier aggregation, the method including calculating interferences regarding a plurality of interference paths between an adjacent cell and serving cell; determining weighted values for the plurality of interference paths in the serving cell; calculating an accumulated value (accumulated margin or accumulated interference) regarding the plurality of interference paths based on the weighted values in the serving cell; determining a component carrier to be used in the carrier aggregation based on the accumulated value calculated in the serving cell; and performing the carrier aggregation based on the component carrier determined.

Abstract: Disclosed is an apparatus for converting a frequency. The apparatus includes: an oscillator configured to generate a first oscillation signal having a first oscillation frequency which is obtained by subtracting an input frequency from a carrier frequency of any one carrier signal among a first to a n-th carrier signals (n is a natural number), and generate a second oscillation signal having a second oscillation frequency which is obtained by adding the input frequency to a carrier frequency of any one carrier signal among a (n+1)-th to a 2n-th carrier signals; and a mixer configured to mix and output the first oscillation signal or the second oscillation signal with an input signal having the input frequency.

Abstract: Disclosed herein are a method and a system for performing initial ranging in a cognitive radio network The method for performing initial ranging in a cognitive radio network includes: detecting signals received in one or more ranging sections; estimating a tint time offset based on a correlation between subcarrier indices of the signals detected in the one or more ranging sections; estimating a second time offset based on correlations for the signals detected in the one or more ranging sections and a plurality of codes that are predetermined and detecting an initial ranging code among the plurality of codes; and estimating a time offset of a CPE performing initial ranging with the detected initial ranging code using the first time offset and the second time offset that are estimated.

Abstract: A wireless device of a communication system randomly selects a backoff counter at a contention window interval corresponding to a contention window size that is determined according to a backoff stage, attempts packet transmission, when the backoff counter becomes 0 while reducing the backoff counter, when a radio channel is in an idle status, and increases the contention window size while increasing the backoff stage by 1 according to a first predetermined condition. In this case, as the backoff stage increases, a contention window size has a concave down increasing form.

Abstract: Disclosed is a resource allocating method of a base station, which includes receiving information on an existence signal of another base station or a coexistence frame in a transmission frame of another base station from a terminal, making time synchronization with another base station and frame synchronization with the coexistence frame of another base station coincide with each other, and allocating a signal transmission frame so as not to overlap the signal transmission frame in the transmission frame of another base station.

Abstract: When a feature of the present invention is summarized, disclosed is a frame structure of transmitted and received data in a wireless communication system, including: a plurality of uplink subframes (UL) or downlink subframes (DL) for transmitting and receiving data; and a coexistence synchronization signal preamble for frequency coexistence among asynchronous cells.

Abstract: Disclosed are an apparatus and a method for coexistence of heterogeneous services of a user terminal, which can enhance performance of a wireless communication network by simultaneously providing heterogeneous services such as an LTE-U service and a WiFi service to coexist without signal interference in unlicensed bands through effectively performing selection of a frequency band and selection of a transmission spectrum type in respective service modules of the user terminal.

Abstract: An exemplary embodiment of the present information discloses a base station which transmits a discovery reference signal (DRS) in an unlicensed band, including: a transmission control unit which sets different timings to transmit the DRS for each of a plurality of channels; and a communication unit which transmits the DRS to the outside through the plurality of channels based on the set timing.

Abstract: Disclosed is a method for allocating a resource of a terminal. The method includes: receiving downlink data from a base station; and allocating a resource for a device-to-device communication to a sub-frame by considering a hybrid ARQ (HARQ) transmission delay with respect to the received downlink data.

Abstract: Disclosed is an apparatus for converting a frequency. The apparatus includes: an oscillator configured to generate a first oscillation signal having a first oscillation frequency which is obtained by subtracting an input frequency from a carrier frequency of any one carrier signal among a first to a n-th carrier signals (n is a natural number), and generate a second oscillation signal having a second oscillation frequency which is obtained by adding the input frequency to a carrier frequency of any one carrier signal among a (n+1)-th to a 2n-th carrier signals; and a mixer configured to mix and output the first oscillation signal or the second oscillation signal with an input signal having the input frequency.

Abstract: Disclosed is a communication method for coexisting with a non-licensed band communication system of a non-licensed band in a licensed band communication system. The method includes: transmitting a signal by a transmitter in order to operate in a non-licensed band, when the signal is a transmission target signal having frames and a wireless local area network (WLAN) preamble signal is inserted to the front of each frame of the transmission target signal; and extracting the WLAN preamble signal from the signal of the transmitter by a receiver to synchronize with the transmitter.

Abstract: The present disclosure relate to a spectrum sensing method and a spectrum sensing device. The spectrum sensing method includes: (a) sampling a received signal: (b) calculating a first operation value relating to a strength of the received signal based on the sampled signal; (c) searching for a first frequency band having the largest correlation with an input signal based on the sampled signal; (d) calculating a first residual component signal by removing a signal component in the first frequency band from the received signal; (e) calculating a second operation value relating to a strength of the first residual component signal; and (f) determining whether the frequency band occupied in the received signal is present based on a relative value of the first operation value and the second operation value.