Abstract: Provided is a terminal and an access point in an active mode for multi-user transmission opportunity (TXOP) power saving that may decrease power consumption by changing an operation state of the terminal from an awake state to a sleep state if there is no stream of data to be transmitted during a TXOP duration.

Abstract: Provided is a communication system using a space division multi-user multiple input multiple output (SD-MIMO) communication method. A transmission apparatus may transmit, to each of terminals included within a coverage, common control information commonly transmitted to the terminals and individual control information individually transmitted to each of the terminals. The transmission apparatus does not precode the common control information and transmits the non-precoded common control information. The transmission apparatus precodes the individual control information and transmits the precoded individual control information.

Abstract: A method and apparatus for transmitting and/or receiving a signal in a multiple input multiple output (MIMO) system are provided. An apparatus for transmitting a signal in a multiple input multiple output (MIMO) system includes an input unit to receive NT symbol streams in parallel, where NT is an integer greater than or equal to 2, a multiple signal generating unit to generate NT multiple signals having a transmit diversity gain by applying a cyclic delay of a different pattern to each of the NT symbol streams, and a multiple signal providing unit to provide the generated NT multiple signals to NT transmit antennas, respectively, based on a predetermined transmit antenna index of each of the NT transmit antennas.

Abstract: A wireless power transmission apparatus includes a resonator configured to transmit power to another resonator, and a power supply unit configured to supply power to the resonator. The apparatus further includes a switching unit including a transistor configured to be turned on to connect the power supply unit to the resonator, and to be turned off to disconnect the power supply unit from the resonator, based on a control signal, and a diode connected in series to the transistor.

Abstract: Provided are a method and apparatus for wirelessly transmitting energy. A wireless energy transmitter may perform sampling to obtain first samples from an alternating current (AC) signal that is induced at an energy transmission (TX) end, and may correct symbol synchronization based on a difference between a sum of absolute values of the first samples and a sum of absolute values of second samples sampled during a symbol interval in which synchronization matching is performed between a switch of the energy TX end and a switch of the energy RX end.

Abstract: Provided is a data communication method and apparatus based on a sequential response protocol that is applicable to a multiple user multiple input and multiple output (MU-MIMO) system. The data communication apparatus may include response indexes (RIs) with respect to multiple terminals in at least one spatio-temporal stream to be transmitted to the multiple terminals, and the response indexes may be information associated with a transmission sequence of data to be transmitted by the multiple terminals.

Abstract: Provided is a data transmission system of providing preambles of different classes according to a characteristic of a terminal. A terminal having constraints on using a power with respect to a data reception may receive only a preamble of a particular class and thus decrease a power consumption. A general terminal may receive preambles of plural classes and quickly receive data.

Abstract: Provided is a terminal and an access point in an active mode for multi-user transmission opportunity (TXOP) power saving that may decrease power consumption by changing an operation state of the terminal from an awake state to a sleep state if there is no stream of data to be transmitted during a TXOP duration.

Abstract: A method of selecting an interface by a hub, includes searching for a device of the hub, and setting an optimal interface to communicate with the device. The method further includes transmitting data to the device through the optimal interface.

Abstract: A wireless power receiver includes a receiving unit configured to wirelessly receive power through a resonance between a source resonator and a target resonator. The wireless power receiver further includes a control unit configured to connect the target resonator to at least one capacitor to control a range of a voltage output from the target resonator.

Abstract: A data reception apparatus configured to discharge, prior to receiving data from an energy receiving apparatus, energy stored in a source resonator during a mutual resonance between the source resonator and a target resonator, and demodulate data received from the energy receiving apparatus based on an amount of energy reflected from the target resonator after the energy stored in the source resonator is discharged.

Abstract: Provided is a communication method of an access point and a terminal that may decrease power consumption by changing an operation state of a terminal from an awake state to a sleep state when there is no stream to be transmitted to the terminal during a transmission opportunity (TXOP).

Abstract: A wireless energy transmission apparatus wirelessly transmits energy through resonance between a source resonator and a target resonator. The apparatus scans an amount of energy stored in the source resonator for a scanning period, calculates a total amount of energy stored in the source resonator and the target resonator during an off-resonant interval between the source resonator and the target resonator based on the amount of energy scanned, and estimates an amount of energy induced in the target resonator based on the amount of energy stored in the source resonator and the total amount of energy calculated.

Abstract: An apparatus and a method for processing a signal, and for estimating a point corresponding to a maximum slope from an envelope of an input signal, are provided. A signal processing apparatus includes an envelope detecting unit configured to detect an envelope of an input signal. The signal processing apparatus further includes a correcting unit configured to correct slopes, each of the slopes being between respective points of the envelope, based on information on a clipping interval of the envelope. The signal processing apparatus further includes an estimating unit configured to estimate a point, of the envelope, in which a corrected slope, among the corrected slopes, includes a maximum value.

Abstract: An apparatus and a method for wirelessly receiving and transmitting energy are provided. A wireless energy receiving apparatus in a terminal configured to wirelessly receive energy through mutual resonance between a resonator of an energy supply apparatus configured to supply the energy and a resonator of the terminal, includes an energy measuring unit configured to measure an amount of energy stored in the terminal. The wireless energy receiving apparatus further includes a control unit configured to change a state of the resonator of the terminal from a non-resonant state to a resonant state when the measured amount of energy is less than or equal to a predetermined threshold.

Abstract: A method and an apparatus for detecting an envelope using a difference between sampling signals are provided. The method includes generating sampling sets based on sampling signals of a modulated signal, and determining a sampling set from the sampling sets. The method further includes determining an envelope component value associated with a sampling signal among sampling signals included in the determined sampling set, based on a difference between the sampling signals included in the determined sampling set, and a difference between sampling signals included in each of the sampling sets other than the determined sampling set. The method further includes detecting an envelope of the modulated signal based on the envelope component value.

Abstract: Disclosed are a data receiving apparatus that may discriminate a type of a received data frame, and a data transmission apparatus that may apply a constellation mapping scheme to a data frame so that a data receiving apparatus may discriminate the data frame in accordance with the constellation mapping scheme applied to the data frame.

Abstract: An apparatus for wirelessly transmitting energy based on a frame is provided. The apparatus includes a transmitter configured to transmit, to at least one reception device, energy in a frame unit through a mutual resonance between a source resonator and a plurality of target resonators, and a controller configured to determine information included in the frame based on whether energy is transmitted to the at least one reception device, or based on whether data is transmitted to the at least one reception device.

Abstract: A method and apparatus for security of communication devices that communicate with each other in a near field are provided. A Near Field Communication (NFC) security apparatus may detect the presence of a neighboring device other than communication devices, based on a change in a near field. In response to detecting the presence of the neighboring device, the NFC security apparatus may control an amount of energy transmitted by the communication devices such that the neighboring device may be prevented from accurately receiving a signal transmitted between the communication devices.

Abstract: A communication security method and apparatus of a first node and a second node are provided. The first node and the second node communicate with each other based on a full duplex communication scheme using a near field. In the communication security method and apparatus, information to be transmitted may be encrypted based on received information and the encrypted information may be transmitted, in a TX node and an RX node. The communication security method and apparatus prevent an additional node from decrypting the information, and ensure transmission and reception of reliable data. In addition, the communication security method and apparatus prevent information from being decrypted in a physical layer, by periodically or aperiodically exchanging a new encryption key.