Abstract: A method of estimating a channel of a base station in a communication system using an IRS may comprise: receiving a first signal through a direct path between a terminal and the base station from the terminal and a second signal through an indirect path through the IRS from the terminal; estimating a first angle of arrival of the second signal received from the IRS; estimating a second angle of arrival of a signal transmitted to the IRS by the terminal based on the estimated first angle of arrival; estimating a third angle of arrival of the first signal received from the terminal based on the estimated first angle of arrival; and estimating path gains on the direct path and the indirect path based on the estimated first angle of arrival to the estimated third angle of arrival.

Abstract: Provided is a method for feeding back a channel quality indicator (CQI) by a terminal. The terminal receives, from a base station, at least one reference signal through at least one of multiple beams of the base station. The terminal measures a signal-to-interference plus noise ratio (SINR) for the at least one reference signal. The terminal determines a first level corresponding to the measured SINR among levels of a first CQI. In addition, the terminal feeds back the first CQI having the first level to the base station.

Abstract: There are provided an antenna apparatus and a method of handover using the antenna apparatus. The antenna apparatus may comprise a plurality of antenna elements forming a plurality of beams in a predetermined service area. The plurality of antenna elements are arranged in a plurality of rows, and a number of antenna elements included in an uppermost row of the plurality of rows is smaller than a number of antenna elements included in a downmost row of the plurality of rows, and differences between center angles of beams formed by the antenna elements included in the downmost row are larger than differences between center angles of beams formed by the antenna elements included in the uppermost row.

Abstract: A method in which a base station transmits pilot signals in a multiple-antenna communication system is provided. The base station includes some of the plurality of pilot signals distinguished by at least one of time domain symbols, subcarriers, and orthogonal codes in a first set to which a first random number is applied. The base station includes the remaining pilot signals, excluding the pilot signals that are included in the first set, in a second set that uses the same resources as used by the first set and to which a second random number different from the first random number is applied. The base station transmits at least one of the pilot signals that belong to the first set and the second set.

Abstract: In a communications system using a plurality of beams, a terminal determines a beam to be communicated with the terminal among the plurality of beams, determines one sequence among sequences allocated to the determined beam as a beam based random access preamble, and transmits the beam based random access preamble through the determined beam. In addition, if a random access response for the beam based random access preamble is not received from a base station for a set interval, the terminal determines one sequence among sequences in a cell based random access preamble collection as a cell based random access preamble and transmits the cell based random access preamble.

Abstract: There are provided an antenna apparatus and a method of handover using the antenna apparatus. The antenna apparatus may comprise a plurality of antenna elements forming a plurality of beams in a predetermined service area. The plurality of antenna elements are arranged in a plurality of rows, and a number of antenna elements included in an uppermost row of the plurality of rows is smaller than a number of antenna elements included in a downmost row of the plurality of rows, and differences between center angles of beams formed by the antenna elements included in the downmost row are larger than differences between center angles of beams formed by the antenna elements included in the uppermost row.

Abstract: There are provided an antenna apparatus and a method of handover using the antenna apparatus. The antenna apparatus may comprise a plurality of antenna elements forming a plurality of beams in a predetermined service area. The plurality of antenna elements are arranged in a plurality of rows, and a number of antenna elements included in an uppermost row of the plurality of rows is smaller than a number of antenna elements included in a downmost row of the plurality of rows, and differences between center angles of beams formed by the antenna elements included in the downmost row are larger than differences between center angles of beams formed by the antenna elements included in the uppermost row.

Abstract: In a communications system using a plurality of beams, a terminal determines a beam to be communicated with the terminal among the plurality of beams, determines one sequence among sequences allocated to the determined beam as a beam based random access preamble, and transmits the beam based random access preamble through the determined beam. In addition, if a random access response for the beam based random access preamble is not received from a base station for a set interval, the terminal determines one sequence among sequences in a cell based random access preamble collection as a cell based random access preamble and transmits the cell based random access preamble.

Abstract: A method in which a base station transmits pilot signals in a multiple-antenna communication system is provided. The base station includes some of the plurality of pilot signals distinguished by at least one of time domain symbols, subcarriers, and orthogonal codes in a first set to which a first random number is applied. The base station includes the remaining pilot signals, excluding the pilot signals that are included in the first set, in a second set that uses the same resources as used by the first set and to which a second random number different from the first random number is applied. The base station transmits at least one of the pilot signals that belong to the first set and the second set.

Abstract: A method for transmitting downlink control information in a base station that operates a plurality of beams in one cell includes: configuring an individual control channel region allocated to each of the plurality of beams; configuring a shared control channel region shared with first and second beams that are adjacent to each other among the plurality of beams; allocating a control channel of a terminal positioned in a service coverage of the first beam to one of an individual control channel region of the first beam and the shared control channel region shared with the first and second beams; and in a case where the control channel of the terminal is allocated to the shared control channel region shared with the first and second beams, forming the first and second beams such that user control information of the terminal is transmitted through the shared control channel region shared with the first and second beams.

Abstract: When a terminal of a mobile communication system using a plurality of beams receives information on a channel quality indicator (CQI) transmission mode from a base station, the terminal measures a CQI of a beam to feed back the CQI information according to the CQI transmission mode, transmits information of the beam to feed back the CQI information according to the CQI transmission mode, and thereafter, feeds back the measured CQI information of the beam to the base station.

Abstract: A base station allocates a first frequency resource and a first time resource for first information that is included in a first physical channel and second information that is included in a second physical channel. The base station multi-transmits the first physical channel and the second physical channel through spatial multiplexing.

Abstract: Provided is a method for feeding back a channel quality indicator (CQI) by a terminal. The terminal receives, from a base station, at least one reference signal through at least one of multiple beams of the base station. The terminal measures a signal-to-interference plus noise ratio (SINR) for the at least one reference signal. The terminal determines a first level corresponding to the measured SINR among levels of a first CQI. In addition, the terminal feeds back the first CQI having the first level to the base station.

Abstract: A method and apparatus for simultaneously transmitting data to a plurality of terminals are provided. The method includes: selecting a plurality of simultaneous transmitting terminals based on a signal-to-noise ratio (SNR) of the plurality of terminals; allocating a power rate of the plurality of simultaneous transmitting terminals to each of the plurality of simultaneous transmitting terminals; modulating each of the data according to a modulation method that is determined based on the power rate; and transmitting the modulated data according to the power rate.

Abstract: Disclosed herein relates to a resource allocation method for a machine type communication (MTC) device. The resource allocation method for the MTC device includes allocating a control channel with respect to a user terminal to a first time domain of a sub frame, and mixing at least one of a control channel with respect to the at least one MTC device, a data channel with respect to the user terminal, and a data channel with respect to the MTC device in a second time domain of the sub frame, and allocating the mixed channel to the second time domain of the sub frame. Accordingly, in a wireless communication system, control information and data may be transmitted and received to and from the MTC device while maintaining compatibility with the user terminal.

Abstract: Disclosed are a method for generating a random access signal of a machine type communication (MTC) device using a narrow bandwidth, and an MTC device. The method generates a random access signal by allocating a position in a frequency domain of a random access signal dedicated to the MTC device, that is, a position of a frequency for transmission of a random access preamble, to a center position of a base station system bandwidth, or by shifting a center frequency of the MTC device to a position of a random access frequency allocated for a legacy LTE terminal by a base station.

Abstract: In a method of mitigating inter-cell interference, terminals are grouped into groups. A base station transmits data to a first terminal belonging to a first group among the groups, without cooperation with a neighboring base station. The base station transmits data to a second terminal belonging to a second group among the groups, through cooperation with the neighboring base station.

Abstract: A mobile station includes a plurality of mobile station antennas that receive at least one independent training signal from a plurality of base station antennas, and estimates a downlink channel formed by each of a plurality of base station antennas and each of the mobile station antennas by using the at least one independent training signal. The mobile station generates a beam vector by using the downlink channel, and forms transmission beams in the plurality of mobile station antennas for transmitting a signal to an uplink.

Abstract: A method of determining a position of a terminal in a communication system using multiple beams is provided. The method includes receiving a first beam from a first point, receiving a second beam from a second point, and determining a position of the terminal by use of information about the first beam and information about the second beam, so that in a case in which two or more effective beams are received in a system using multiple beams, the position of the terminal is determined by use of the angle of a beam, and information about coordinates of departure of a beam and/or coordinates of final arrival of a beam without using a positioning device, such as GPS.

Abstract: There are provided an antenna apparatus and a method of handover using the antenna apparatus. The antenna apparatus may comprise a plurality of antenna elements forming a plurality of beams in a predetermined service area. The plurality of antenna elements are arranged in a plurality of rows, and a number of antenna elements included in an uppermost row of the plurality of rows is smaller than a number of antenna elements included in a downmost row of the plurality of rows, and differences between center angles of beams formed by the antenna elements included in the downmost row are larger than differences between center angles of beams formed by the antenna elements included in the uppermost row.