Abstract: A method and apparatus for an interference-aware resource-sharing scheme for multiple D2D group communications is provided. The method for interference-aware resource-sharing scheme for multiple D2D communications includes initializing a D2D communication request and deciding the numbers of D2D pairs and CUEs, grouping D2D pairs according to the decided numbers of the D2D pairs and CUEs, selecting target CUEs for the grouped D2D pairs to share frequency resources, applying interference alignment to the D2D groups, updating the set of the CUEs and D2D pairs, and moving the rest of the D2D pairs to the orthogonal group.

Abstract: A method and apparatus for an interference-aware resource-sharing scheme for multiple D2D group communications is provided. The method for interference-aware resource-sharing scheme for multiple D2D communications includes initializing a D2D communication request and deciding the numbers of D2D pairs and CUEs, grouping D2D pairs according to the decided numbers of the D2D pairs and CUEs, selecting target CUEs for the grouped D2D pairs to share frequency resources, applying interference alignment to the D2D groups, updating the set of the CUEs and D2D pairs, and moving the rest of the D2D pairs to the orthogonal group.

Abstract: There is provided a method for removing interference between a femto-cell and a macro-cell, comprising: allocating communication resources to a plurality of femto-cell user devices; receiving uplink signals between a plurality of the macro-cell user devices and a macro-cell base station from the plurality of the macro-cell user devices; detecting a high interference indicator (HII) from the uplink signals; deciding a macro-cell user device, which has transmitted the high interference indicator, as an interference subject user device; extracting channel state information (CSI) from the uplink signal received from the interference subject user device; and changing and allocating the communication resource allocated to the femto-cell user device based on the extracted channel state information.

Abstract: A power control system and method to mitigate interference in a heterogeneous network is provided. A power control method to mitigate interference may include: receiving a link connection request from a femto terminal; transmitting a downlink signal when the link connection request is allowed; receiving information of a macro terminal present around a femto base station; controlling a power of the downlink signal in response to a high interference indicator (HII) report being included in the received information of the macro terminal; and controlling the power of the downlink signal based on a priority of service while satisfying predetermined constraints, in response to the HII report in a state in which the power of the downlink signal is decreased up to a predetermined required power.

Abstract: A method and system to dynamically allocate a frequency based on a priority of quality of experience (QoE) is disclosed. A method to dynamically allocate a frequency may include: securing a predetermined frequency band and a bonus frequency band for a macrocell; allocating the predetermined frequency band and the bonus frequency band to a macro terminal located in the macrocell; allocating the bonus frequency band based on the priority of service in a subsequent time slot when a frequency band comprising the predetermined frequency band and the bonus frequency band is not allocated to the macro terminal.

Abstract: There is provided a method for removing interference between a femto-cell and a macro-cell, comprising: allocating communication resources to a plurality of femto-cell user devices; receiving uplink signals between a plurality of the macro-cell user devices and a macro-cell base station from the plurality of the macro-cell user devices; detecting a high interference indicator (HII) from the uplink signals; deciding a macro-cell user device, which has transmitted the high interference indicator, as an interference subject user device; extracting channel state information (CSI) from the uplink signal received from the interference subject user device; and changing and allocating the communication resource allocated to the femto-cell user device based on the extracted channel state information.

Abstract: A power control system and method to mitigate interference in a heterogeneous network is provided. A power control method to mitigate interference may include: receiving a link connection request from a femto terminal; transmitting a downlink signal when the link connection request is allowed; receiving information of a macro terminal present around a femto base station; controlling a power of the downlink signal in response to a high interference indicator (HII) report being included in the received information of the macro terminal; and controlling the power of the downlink signal based on a priority of service while satisfying predetermined constraints, in response to the HII report in a state in which the power of the downlink signal is decreased up to a predetermined required power.

Abstract: A method and system to dynamically allocate a frequency based on a priority of quality of experience (QoE) is disclosed. A method to dynamically allocate a frequency may include: securing a predetermined frequency band and a bonus frequency band for a macrocell; allocating the predetermined frequency band and the bonus frequency band to a macro terminal located in the macrocell; allocating the bonus frequency band based on the priority of service in a subsequent time slot when a frequency band comprising the predetermined frequency band and the bonus frequency band is not allocated to the macro terminal.

Abstract: There is provided a signal detecting method using constellation set grouping in a spatial multiplexing multiple input multiple output system. The signal detecting method includes dividing a set of candidate symbols, a constellation set into a plurality of subsets by grouping the constellation set; dividing a tree search process of a QR-decomposition with M-algorithm (QRDM) algorithm into a plurality of partial detection phases; and performing the plurality of divided partial detection phases in parallel or iteratively.

Abstract: Disclosed is an adaptive transmit and receive method and device in a multiple-antenna wireless communication system. A transmit mode comprises different main transmit modes each of which includes one or both of a sub-transmit mode based on STBC and a sub-transmit mode based on SM. A receiver calculates an STBC performance parameter and a SM performance parameter, and a transmitter uses the parameters to determine a main transmit mode with maximum data rates and select a sub-transmit mode for minimizing power consumption. The transmitter channel-encodes, modulates and antenna-maps input data according to the selected transmit mode, and outputs results to the receiver. The receiver antenna/symbol-demodulates and channel-decodes the received data.

Abstract: Disclosed herein is a ranging apparatus and method. The ranging apparatus includes a correlation unit for correlating OFDMA reception signals with inverse fast Fourier transformed ranging codes, and outputting correlation result values. A threshold determination unit determines a threshold value depending on characteristics of the reception signals. A comparison unit estimates a delay time by selecting a maximum value from among the correlation result values, and detects a ranging code by comparing the maximum value with the threshold value, and then outputs and feeds back the ranging code and the delay time when the maximum value is equal to or greater than the threshold value. A weight multiplication unit delays the ranging code by the delay time, multiplies a weight by the delayed ranging code, and outputs a resulting value. A calculation unit subtracts the resulting value from the reception signals, and provides adjusted reception signals.

Abstract: Disclosed is an adaptive transmit and receive method and device in a multiple-antenna wireless communication system. A transmit mode comprises different main transmit modes each of which includes one or both of a sub-transmit mode based on STBC and a sub-transmit mode based on SM. A receiver calculates an STBC performance parameter and a SM performance parameter, and a transmitter uses the parameters to determine a main transmit mode with maximum data rates and select a sub-transmit mode for minimizing power consumption. The transmitter channel-encodes, modulates and antenna-maps input data according to the selected transmit mode, and outputs results to the receiver. The receiver antenna/symbol-demodulates and channel-decodes the received data.

Abstract: Disclosed is an adaptive transmit and receive method and device in a multiple-antenna wireless communication system. A transmit mode comprises different main transmit modes each of which includes one or both of a sub-transmit mode based on STBC and a sub-transmit mode based on SM. A receiver calculates an STBC performance parameter and a SM performance parameter, and a transmitter uses the parameters to determine a main transmit mode with maximum data rates and select a sub-transmit mode for minimizing power consumption. The transmitter channel-encodes, modulates and antenna-maps input data according to the selected transmit mode, and outputs results to the receiver. The receiver antenna/symbol-demodulates and channel-decodes the received data.

Abstract: Provided are a dynamic resource allocation method based on frequency reuse partitioning for an Orthogonal Frequency Division Multiple Access (OFDMA) system, and a frame transmission method therefor. The dynamic resource allocation method includes: a) dividing a coverage into cells based on frequency reuse partitioning; b) selecting a candidate user to receive a channel allocated thereto based on the ratio; c) acquiring distance information for the candidate user; and d) checking whether the candidate user is in an inner or outer cell area based on the distance information. If the candidate user is in the inner cell area, a subchannel group among subchannel groups having a Frequency Reuse Factor (FRF) lower than a threshold value is selected and subcarriers of the selected subchannel group is allocated. If the candidate user is in the outer cell area, a subchannel group among subchannel groups having a FRF higher than the threshold value is selected.

Abstract: Provided is a method for retransmitting data based on antenna scheduling in a MIMO system to which a spatial multiplexing technique is applied. The method includes the steps of: (a) at a transmitter side, modulating an input packet into transmittable data to transmit to a receiver side; (b) at the receiver side, estimating channel values from the packet transmitted from the transmitter side, and selecting transmitting and receiving antennas for transmitting the next packet from the estimated channel values; (c) detecting whether an error is present in the packet or not, and transmitting a feedback signal to the transmitter side, the feedback signal including information on whether or not to transmit the packet and a list of the selected transmitting antennas; and (d) at the transmitter side, retransmitting the transmitted packet or transmitting the next packet through the transmitting antennas designated by the receiver side depending on the feedback signal.

Abstract: Provided is a method for dynamic resource allocation of uplink and downlink in an OFDMA/TDD cellular system. The method for dynamic resource allocation of uplink in an OFDMA/TDD cellular system includes the steps of determining the number of sub-channels which can be allocated to each user through an FLR algorithm; performing channel allocation for a first frame through a round-robin algorithm in which channel information is not needed; performing dynamic channel allocation for a next frame through uplink channel information measured by uplink channel sounding; and performing power control.

Abstract: The present invention relates to a system for canceling co-channel interference (CC) in a cellular orthogonal frequency division multiplexing (OFDM) system. The system canceling co-channel interference (CCI) in a cellular orthogonal frequency division multiplexing (OFDM) system comprises a mobile station (MS) receiver including a feedback generation unit for generating a feedback to a base station (BS) so as to control a transmission power of the transmitting frame of the BS, and a maximum likelihood estimation (MLE) CCI cancellation unit for canceling CCI signals arriving from neighbor cells; and a BS transmitter including a closed-loop power control unit for controlling the transmission power of the transmitting frame according to the feedback received from the MS such that received power of desired signal at the MS receiver is different from that of an interferer signal.

Abstract: Disclosed herein is a ranging apparatus and method. The ranging apparatus includes a correlation unit for correlating OFDMA reception signals with inverse fast Fourier transformed ranging codes, and outputting correlation result values. A threshold determination unit determines a threshold value depending on characteristics of the reception signals. A comparison unit estimates a delay time by selecting a maximum value from among the correlation result values, and detects a ranging code by comparing the maximum value with the threshold value, and then outputs and feeds back the ranging code and the delay time when the maximum value is equal to or greater than the threshold value. A weight multiplication unit delays the ranging code by the delay time, multiplies a weight by the delayed ranging code, and outputs a resulting value. A calculation unit subtracts the resulting value from the reception signals, and provides adjusted reception signals.

Abstract: Disclosed is an adaptive transmit and receive method and device in a multiple-antenna wireless communication system. A transmit mode comprises different main transmit modes each of which includes one or both of a sub-transmit mode based on STBC and a sub-transmit mode based on SM. A receiver calculates an STBC performance parameter and a SM performance parameter, and a transmitter uses the parameters to determine a main transmit mode with maximum data rates and select a sub-transmit mode for minimizing power consumption. The transmitter channel-encodes, modulates and antenna-maps input data according to the selected transmit mode, and outputs results to the receiver. The receiver antenna/symbol-demodulates and channel-decodes the received data.

Abstract: Disclosed are an adaptive pilot symbol assignment method that flexibly controls the number of transmit antennas according to each user's moving speed, channel status, or user request, and assigns proper pilot symbols in the downlink of an OFDMA (Orthogonal Frequency Division Multiplexing Access) based cellular system; and a sub-carrier allocation method for high-speed mobile that allocates some sub-carriers to assign proper pilot symbols for ultrahigh-speed mobile users, and the rest of the sub-carriers to the other users to assign proper pilot symbols to the users, on the assumption that the ultrahigh-speed mobile users have a traffic volume almost insignificant to the whole traffic volume.