Abstract: A method and an apparatus for transmitting a signal by using a plurality of radio units (RUs) to a user equipment (UE). The apparatus is configured to: determine an RU set including at least two RUs of the plurality of the RUs based on a feedback regarding a received strength of a transmission beam formed by the plurality of the RUs, wherein the feedback is received from the UE; determine a distributed precoding matrix of which a diversity order is predetermined based on information about an RU included in the RU set; and perform a precoding based on the distributed precoding matrix and transmitting a precoded signal to the UE through the RU set.

Abstract: A wireless communication method and apparatus in a wireless local area network (WLAN) system are disclosed. A wireless communication method according to one embodiment may include generating a high-efficiency Wi-Fi (HEW) frame including at least one of an HEW-SIG-A field and an HEW-SIG-B field which include channel information for communications according to an Orthogonal Frequency-Division Multiple Access (OFDMA) mode, and transmitting the generated HEW frame to a reception apparatus.

Abstract: Provided is a wireless communication method performed at an access point to enhance the transmission efficiency in a wireless local area network (WLAN) system, the method including scheduling a transmission time of an enhanced traffic indicator map (TIM) frame based on a type of a station, and transmitting a second beacon including the enhanced TIM frame to the station at a point in time aside from a transmission point in time of a first beacon.

Abstract: The present application relates to a method of generating a downlink frame. The method of generating the downlink frame includes: generating a first short sequence and a second short sequence indicating cell group information; generating a first scrambling sequence and a second scrambling sequence determined by the primary synchronization signal; generating a third scrambling sequence determined by the first short sequence and a fourth scrambling sequence determined by the second short sequence; scrambling the short sequences with the respective scrambling sequences; and mapping the secondary synchronization signal that includes the first short sequence scrambled with the first scrambling sequence, the second short sequence scrambled with the second scrambling sequence and the third scrambling sequence, the second short sequence scrambled with the first scrambling sequence and the first short sequence scrambled by the second scrambling sequence and the fourth scrambling sequence to a frequency domain.

Abstract: A wireless communication method and apparatus in a wireless local area network (WLAN) system are disclosed. A wireless communication method according to one embodiment may include generating a high-efficiency Wi-Fi (HEW) frame including at least one of an HEW-SIG-A field and an HEW-SIG-B field which include channel information for communications according to an Orthogonal Frequency-Division Multiple Access (OFDMA) mode, and transmitting the generated HEW frame to a reception apparatus.

Abstract: A radio unit (RU) in a directional communication network establishes a connection with a first antenna among two antennas of a first TE in a first moving object that first enters a serving duration of the RU according to a network access request from the first antenna, and when receiving the network access request from a second antenna among two antennas of a second TE in a second moving object that next enters the serving duration, the RU processes the network access request from the second antenna based on network access priority of the second antenna and network access priority of the first antenna to which the connection is established.

Abstract: A method for transmitting and receiving a signal using steps of transmitting an uplink signal to a base station in a duration of an uplink pilot time slot (UpPTS) of a special subframe, and waiting for a guard time (GT) before receiving a downlink signal from the base station after the transmission of the uplink signal, and a terminal transmitting and receiving a signal by using the method.

Abstract: When a plurality of terminals share the same resources in a wireless communication system, and when control information such as acknowledgement/negative acknowledgement (ACK/NAK) information or scheduling information is transmitted, a method of efficiently performing code division multiplexing (CDM) is required to distinguish the plurality of terminals. In particular, it is necessary to develop a method by which a code sequence of CDM can be selected and used according to each cell condition. Provided is a method of forming a signal in a wireless communication system in which a plurality of terminals commonly share frequency and time resources. The method includes the operations of receiving condition information in a cell; selecting one of a plurality of time domain orthogonal sequences having different lengths, according to the condition information; and allocating the selected time domain orthogonal sequence to a control signal symbol block.

Abstract: An operation method of a terminal in a communication system includes receiving a message from a base station, the message including physical random access channel (PRACH) configuration information indicating a PRACH slot; determining a start symbol to which a PRACH is mapped among symbols constituting the PRACH slot based on a type of the PRACH slot; mapping the PRACH from the start symbol in the PRACH slot; and transmitting the PRACH mapped to the PRACH slot to the base station.

Abstract: Disclosed are a frame transmission method using a selective beamforming and a communication apparatus to perform the frame transmission method. The communication apparatus may determine a beamforming matrix based on classification information in which a plurality of subcarriers used for communication is classified into a plurality of frequency units, may map a long training field (LTF) sequence to the beamforming matrix, and transmit a beamforming training (BF-T) frame including the mapped LTF sequence to a plurality of stations, may receive, from the plurality of stations having receiving the BF-T frame, feedback information generated based on a reception strength of the BF-T frame, and may allocate frequency units to data frames to be transmitted to the plurality of stations based on the feedback information, and transmit the data frames using the allocated frequency units. The reception strength of the BF-T frame may be determined at each station for each frequency unit.

Abstract: A method of performing, by a device, a random access procedure in a radio communication system includes: receiving from a base station RACH configuration information; and transmitting a first message based on the received RACH configuration information. Herein, a plurality of SSBs may be in association with a plurality of preambles, and the first message may be transmitted in a time domain through a plurality of RACH resources.

Abstract: Disclosed are a frame transmission method using a selective beamforming and a communication apparatus to perform the frame transmission method. The communication apparatus may determine a beamforming matrix based on classification information in which a plurality of subcarriers used for communication is classified into a plurality of frequency units, may map a long training field (LTF) sequence to the beamforming matrix, and transmit a beamforming training (BF-T) frame including the mapped LTF sequence to a plurality of stations, may receive, from the plurality of stations having receiving the BF-T frame, feedback information generated based on a reception strength of the BF-T frame, and may allocate frequency units to data frames to be transmitted to the plurality of stations based on the feedback information, and transmit the data frames using the allocated frequency units. The reception strength of the BF-T frame may be determined at each station for each frequency unit.

Abstract: When a plurality of terminals share the same resources in a wireless communication system, and when control information such as acknowledgement/negative acknowledgement (ACK/NAK) information or scheduling information is transmitted, a method of efficiently performing code division multiplexing (CDM) is required to distinguish the plurality of terminals. In particular, it is necessary to develop a method by which a code sequence of CDM can be selected and used according to each cell condition. Provided is a method of forming a signal in a wireless communication system in which a plurality of terminals commonly share frequency and time resources. The method includes the operations of receiving condition information in a cell; selecting one of a plurality of time domain orthogonal sequences having different lengths, according to the condition information; and allocating the selected time domain orthogonal sequence to a control signal symbol block.

Abstract: A base station in a mobile communication system determines the number of slots that are to be used to transmit a synchronization signal in a period of the synchronization signal depending on the number of neighbor cells, allocates a synchronization signal region in which the synchronization signal is to be transmitted to a first slot of the determined number of slots depending on a cell identifier of a serving cell, and allocates a reserved region in which no signal is transmitted to slots other than the first slot among the determined number of slots so as to correspond to a position of the synchronization signal region.

Abstract: A method of searching a cell in a mobile station of a communication system in which a plurality of cells are grouped into a plurality of cell groups, each cell group including at least two cells, includes: detecting a primary synchronization signal and a secondary synchronization signal from a received signal; and identifying a cell based on a combination of the primary synchronization signal and the secondary synchronization signal. The secondary synchronization signal is related to the cell group to which the mobile station belongs and the primary synchronization signal is related to the cell to which the mobile station belongs within the cell group.

Abstract: A method and user equipment for transmitting a message of a random access procedure in a multi-beam system includes: transmitting and retransmitting a message 1 of the RA procedure through a first beam of a plurality of transmission beams of the UE based on power ramping; and retransmitting, if one or more Msg. 2 (RAR) is not successfully received corresponding to the message 1 transmission/retransmission, the message 1 through a second beam of the plurality of transmission beams after switching the first beam to the second beam at a second power level which is the same as or higher than a first power level of the first beam.

Abstract: Provided is a method for generating, by a base station, a common signal commonly required for surrounding terminals of the base station in a massive multiple input multiple output (MIMO) system. The base station generates data commonly required for the surrounding terminals. The base station generates a plurality of beamforming vectors using a time-domain constant amplitude (TCA)-frequency-domain constant amplitude (FCA) sequence having a constant size in a time domain and a frequency domain. Further, the base station generates a plurality of antenna streams corresponding to the common signal by multiplying the plurality of beamforming vectors by the data.

Abstract: Disclosed are a frame transmission method and a communication device performing the same. The communication device may transmit a null data packet (NDP)-announcement (NDP-A) including information on a plurality of communication devices participating in interference alignment and transmit an NDP including a common signal field and a common training field commonly applied to the plurality of communication devices.

Abstract: A method for transmitting and receiving a message for a random access (RA) between user equipment (UE) and a base station in a multi beam system includes: transmitting a synchronization signal (SS) block including a synchronization signal by performing beam sweeping for a multi beam; receiving a message 1 of an RA procedure from the UE; determining an optimal transmission beam to be used to transmit a message 2 of the RA procedure based on information about an association mapping between the SS block and a physical random access channel (PRACH) which is used to transmit the message 1; and transmitting the message 2 by using the optimal transmission beam.

Abstract: In a wireless communication system in which a plurality of base stations each forming a directional beam in one direction are disposed along a predetermined path, each base station estimates a distance from installed in a mobile body moving along the path if the TE enters a cell area of the corresponding base station; and controls the transmission power using a distance from the estimated TE so that a difference between received signal strength of the corresponding base station and the received signal strength of neighboring base stations measured by the TE in a cell boundary area between the base stations does not exceed a predetermined threshold value.