Abstract: Disclosed are an optical signal communication method, and an optical signal transmission device and an optical signal reception device which perform the method. The optical signal communication method may comprise the steps of: receiving input data to be modulated into an optical signal, modulating the input data into the optical signal, and transmitting the optical signal to an optical signal reception device, wherein the optical signal includes a start pulse and an end pulse, and a time interval between the start pulse and the end pulse is determined on the basis of a data value of the input data.

Abstract: Disclosed are an optical signal communication method, and an optical signal transmission device and an optical signal reception device which perform the method. The optical signal communication method may comprise the steps of: receiving input data to be modulated into an optical signal, modulating the input data into the optical signal, and transmitting the optical signal to an optical signal reception device, wherein the optical signal includes a start pulse and an end pulse, and a time interval between the start pulse and the end pulse is determined on the basis of a data value of the input data.

Abstract: Disclosed are an optical signal communication method and device and a biometric data monitoring system using the optical signal communication method and device. An optical signal communication method performed by an optical signal transmitting device includes receiving current input data to be modulated into an optical signal, dividing the received current input data into a plurality of sub-data sets including first sub-data and second sub-data, modulating the current input data into an optical signal including a start pulse, an intermediate pulse, and an end pulse based on the sub-data sets, and transmitting the optical signal to an optical signal receiving device.

Abstract: A method is provided for communications between a responding station and a requesting station. In a wireless local area network, the responding station receives a null data packet announcement (NDPA) frame and a null data packet (NDP) frame for channel sounding, and a first poll frame, from the requesting station. The NDP frame follows the NDPA frame. In response to the first poll frame, the responding station transmits a first feedback data field including beamforming feedback information and signal to noise ratio (SNR) information to the requesting station. The responding station receives a second poll frame including a segment retransmission bitmap field indicating at least one segment of the first feedback data field from the requesting station. In response to the second poll frame, the responding station transmits a second feedback data field including the at least one segment of the first feedback data field to the requesting station.

Abstract: The present invention relates to a method for transmitting and receiving a frame performed by an AP in a wireless communication system. The method includes the steps of: transmitting a PST message providing instructions to transmit a frame to at least one STA; and receiving frames from a first STA and a second STA. The PST message includes first subband information indicating a first subband in which a first frame is transmitted from the first STA and second subband information indicating a second subband in which a second frame is transmitted from the second STA.

Abstract: A method is provided for channel sounding in a wireless local area network. A responding station receives a null data packet announcement (NDPA) frame and a null data packet (NDP) frame for the channel sounding from a requesting station. The NDP frame follows the NDPA frame. The responding station receives a first poll frame from the requesting station. In response to the first poll frame, the responding station transmits a first feedback data field including beamforming feedback information and signal to noise ratio (SNR) information to the requesting station. The responding station receives a second poll frame including a segment retransmission bitmap field indicating at least one segment of the first feedback data field from the requesting station. In response to the second poll frame, the responding station transmits a second feedback data field including the at least one segment of the first feedback data field to the requesting station.

Abstract: A method of link adaptation performed by an access point supporting multi user (MU) multiple input multiple output (MIMO) in wireless local area network system is provided. The method includes transmitting, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme (MCS) request (MRQ) and receiving, from the first station, a MCS feedback (MFB) in response to the MRQ, wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

Abstract: A method, performed by a transceiver, is provided for channel sounding in a wireless local area network. A null data packet announcement (NDPA) frame is received from a transmitter to initiate the channel sounding. A null data packet (NDP) is received from the transmitter, the NDP following the NDPA frame. First feedback data split into a plurality of segments in a single aggregated medium access control protocol data unit (A-MPDU) is transmitted. A retransmission request is received from the transmitter, the retransmission request including a segment retransmission bitmap field indicating at least one segment of the plurality of segments for retransmission. In response to the retransmission request, second feedback data including the at least one segment indicated in the segment retransmission bitmap field is transmitted.

Abstract: The present invention relates to a method of determining a Modulation and Coding Scheme (MCS) feedback in a Wireless Local Area Network (WLAN) system, including an MCS FeedBack (MFB) responder receiving a first frame, including a request message requesting to send the MFB, from an MFB requester and the MFB responder sending the MFB, including a recommended MCS value, to the MFB requester. The recommended MCS value is derived with reference to at least one of unsolicit type information indicative of a type of the MFB, transmit type information indicative of a transmission type of data, coding type information indicative of a coding scheme applied to the data, a group ID indicative of a group of target stations (STAs) to which the data will be transmitted, and MFB bandwidth information indicative of a bandwidth of a channel.

Abstract: A method for a wireless local area network performed by an access point (AP) configured to communicate over a primary subchannel and a secondary subchannel. The AP transmits a frame including a quiet channel element to a receiving station. The quiet channel element indicates that the secondary subchannel is to be quieted during a quiet interval in which the AP tests the secondary subchannel for a presence of radar transmissions and the receiving station does not send any frame to the AP. The quiet channel element includes an AP quiet mode field indicating whether a communication to the AP is allowed within the primary subchannel during the quiet interval. The primary subchannel and the secondary subchannel are quieted during the quiet interval if the AP quiet mode field indicates the communication to the AP is not allowed with the primary subchannel during the quiet interval.

Abstract: Provided are a method and device for processing an uplink (UL) signal in a WLAN system. An access point (AP) receives a request to send (RTS) frame from one station (STA) among a plurality of STAs, transmits a group identifier (ID) of a group to which STAs for performing UL multi user multiple-input multiple-output (MU-MIMO) transmission together with the one STA, among group IDs of a group to which the one STA belongs, and receives UL signals from the STAs which perform the UL MU-MIMO transmission such that the received UL signals are processed.

Abstract: In an aspect, a method of receiving a data unit, performed by an Access Point (AP), in a Wireless LAN (WLAN) system is provided. The method includes transmitting a signal protection frame, the signal protection frame comprising a group ID field indicating a Multiple Input Multiple Output (MIMO) transmission STA group including a first station (STA) and a second STA; and, a spatial stream field indicating a number of spatial streams allocated to each of member STAs included in the MIMO transmission STA group; receiving a first preamble for a first data unit from the first STA; receiving a second preamble for a second data unit from the second STA; and simultaneously receiving the first data unit from the first STA and the second data unit from the second STA.

Abstract: A layered channel access method of a Group Representative-station (GR-STA) in a Wireless Local Area Network (WLAN) system is provided. The method includes receiving a management, including setting information indicative of a first phase and a second phase frame, from an Access Point (AP), receiving a first radio frame from the AP or accessing a channel and sending a second radio frame to the AP during the first phase indicated by the setting information, and receiving a third radio frame from an affiliated STA of a group to which the GR-STA belongs or accessing a channel and sending a fourth radio frame to at least one STA of the group to which the GR-STA belongs during the second phase indicated by the setting information.

Abstract: Disclosed are a method and device for transmitting a frame. The method for transmitting a frame includes a step of generating A-MPDU (aggregate MAC protocol data unit) and a step of transmitting A-MPDU. The A-MPDU includes a first AMPDU subframe and a second A-MPDU subframe, wherein the first A-MPDU subframe includes a data block, and the second AMPDU subframe includes an FEC (Forward Error Correction) coding block which is additionally used in the decoding of the data block. Thus, the STA is capable of preventing unnecessary power consumption of STA by selectively determining whether FEC information is received according to whether an error occurred in the decoded data.

Abstract: A method and a device for reporting a modulation and coding scheme (MCS) feedback in a wireless local area network are provided. A responding station receives, from a requesting station, a requesting Physical layer Protocol Data Unit (PPDU) for requesting a MCS feedback via a plurality of spatial streams. A recommended MCS is estimated under an assumption that the requesting station will transmit at least one first spatial stream among the plurality of spatial streams used for the requesting PPDU, The responding station transmits, to the requesting station, the MCS feedback including a recommended MCS field indicating the recommended MCS and a recommended stream field indicating a number of at least one recommended spatial stream. A number of the at least one first spatial stream used for estimating the recommended MCS is equal to the number of the at least one recommended spatial stream.

Abstract: A method of link adaptation performed by an access point supporting multi user (MU) multiple input multiple output (MIMO) in wireless local area network system is provided. The method includes transmitting, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme (MCS) request (MRQ) and receiving, from the first station, a MCS feedback (MFB) in response to the MRQ, wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

Abstract: The present invention relates to a method for transmitting a frame, which is performed by a transmission station in a wireless LAN system that supports frame transmission and reception on the basis of a first physical layer and a second physical layer. The method comprises the steps of: transmitting a request-to-send (RTS) to a reception station through the first physical layer of the transmission station; receiving, by the reception station, a first clear-to-send (CTS) frame transmitted through the first physical layer of the reception station in response to the RTS frame; and transmitting a second CTS frame through the second physical layer of the transmission station, then transmitting a data frame through the first physical layer of the transmission station.

Abstract: A method of communication based on a receive chain control, performed by a receiver, in a wireless local area network is provided. The method includes: receiving a frame from a transmitter, the frame indicating a multi receive chain operation, activating at least one receive chain, each receive chain processing a received signal transmitted through each spatial stream, and receiving at least one data field from the transmitter through the at least one activated receive chain.

Abstract: A method, performed by a transceiver, is provided for channel sounding in a wireless local area network. A null data packet announcement (NDPA) frame is received from a transmitter to initiate the channel sounding. A null data packet (NDP) is received from the transmitter, the NDP following the NDPA frame. First feedback data split into a plurality of segments in a single aggregated medium access control protocol data unit (A-MPDU) is transmitted. A retransmission request is received from the transmitter, the retransmission request including a segment retransmission bitmap field indicating at least one segment of the plurality of segments for retransmission. In response to the retransmission request, second feedback data including the at least one segment indicated in the segment retransmission bitmap field is transmitted.

Abstract: The present invention relates to a method and device for channel measurement in a wireless LAN system. A station (STA) receives a plurality of sounding frames from an access point (AP), estimates the plurality of sounding frames in order to generate long-term channel state information (LCSI), provides the generated LCSI to the AP as feedback, and receives from the AP a group identifier (ID) management frame comprising information on a group ID determined on the basis of the LCSI.