Abstract: The present disclosure relates to a method and device for communication by a base station in a wireless communication system supporting multiple reconfigurable intelligent surface (RIS) devices. According to an embodiment A method for operating a base station, the method comprises selecting at least two reference reconfigurable intelligent surface (RIS) devices for estimating a position of a user equipment (UE) from among a plurality of RIS devices, estimating position information about the UE using the selected at least two reference RIS devices, receiving an uplink pilot signal of the UE through the selected at least two reference RIS devices; and estimating a multi-RIS channel for the plurality of RIS devices based on the uplink pilot signal of the UE and the estimated position information about the UE.

Abstract: Provided is an active user detection and channel estimation method of a base station in a wireless communication system based on grant-free uplink transmission. The method, according to one embodiment, comprises the steps of: receiving superimposed signals () from k active terminals; by using a first artificial neural network and using the received signals () as input, calculating, for all terminals in a cell of a base station, an estimated probability ({circumflex over (?)}) of each of the terminals being an active terminal; and estimating channels of the active terminals by using a second artificial neural network and using the received signals () and an active user detection result value as input.

Abstract: The disclosure relates to a 5G or a 6th generation (6G) communication system for supporting a higher data transmission rate after a 4th generation (4G) communication system such as LTE. An operating method of a BS in a wireless communication system includes broadcasting a power signal of an IRS, broadcasting an SSB, and requesting receive beam reporting from a control unit of the IRS.

Abstract: The disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as long term evolution (LTE). The disclosure relates to a technique for controlling a base station power using an artificial intelligence based technology to improve an energy efficiency of a communication network. A method performed by a base station of a communication system according to an embodiment of the disclosure may include acquiring state information, determining an active/sleep request indicator (ASRI) based on at least a part of the state information, transmitting at least one of the state information and the ASRI to a central unit, receiving, from the central unit, power control information determined based on the at least one of the state information and the ASRI, and performing a power control based on the received power control information.

Abstract: An operation method of a base station in a time division duplex communication system includes: a step for setting a time period in which a terminal can transmit an uplink in a downlink period; a step for generating a sparse vector signal including information about the time period; and a step for transmitting the sparse vector signal to the terminal. In addition, an operation method of the terminal in the time division duplex communication system includes: a step for receiving a part of a sparse vector signal from the base station; a step for recovering the received sparse vector signal by compressed sensing; and a step for transmitting uplink data in a time period instructed in a downlink period based on the basis of the recovered signal.

Abstract: The disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as long term evolution (LTE). The disclosure relates to a technique for controlling a base station power using an artificial intelligence based technology to improve an energy efficiency of a communication network. A method performed by a base station of a communication system according to an embodiment of the disclosure may include acquiring state information, determining an active/sleep request indicator (ASRI) based on at least a part of the state information, transmitting at least one of the state information and the ASRI to a central unit, receiving, from the central unit, power control information determined based on the at least one of the state information and the ASRI, and performing a power control based on the received power control information.

Abstract: A method by which a transmitting end operates in a wireless communication system comprises the steps of: performing sparse coding on information so as to have sparsity of which the number of non-zero symbols is K; configuring a codebook by including a code for spreading for each user; spreading the coded information by using one or more codes in the codebook; and transmitting a channel by overlapping the spread information. Therefore, even if the number of encoded symbols increases, the number of symbols actually having a value is very sparsely configured such that the complexity of a transmitter and a receiver does not increase, and thus restoration performance improves.

Abstract: An operation method of a base station in a time division duplex communication system includes: a step for setting a time period in which a terminal can transmit an uplink in a downlink period; a step for generating a sparse vector signal including information about the time period; and a step for transmitting the sparse vector signal to the terminal. In addition, an operation method of the terminal in the time division duplex communication system includes: a step for receiving a part of a sparse vector signal from the base station; a step for recovering the received sparse vector signal by compressed sensing; and a step for transmitting uplink data in a time period instructed in a downlink period based on the basis of the recovered signal.

Abstract: The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate than in a 4G communication system such as LTE. The present disclosure relates to uplink transmission in a wireless communication system, and an operating method of a terminal includes mapping codes that are included in at least one codebook onto data symbols. and transmitting the data symbols spread by using the at least one codebook, and the data symbols are used for a base station to detect at least one active terminal including the terminal.

Abstract: The present prevent relates to a method of sparsifying a channel using beamforming in a wireless communication system, the method including inserting pilot symbols into resources allocated among resource elements constituting a time-frequency grid; calculating beamforming weights for sparsifying a beamformed time-domain channel; and beamforming frequency-domain channels of a plurality of antennas mapping the pilot symbols by using the beamforming weights.

Abstract: A method by which a transmitting end operates in a wireless communication system comprises the steps of: performing sparse coding on information so as to have sparsity of which the number of non-zero symbols is K; configuring a codebook by including a code for spreading for each user; spreading the coded information by using one or more codes in the codebook; and transmitting a channel by overlapping the spread information. Therefore, even if the number of encoded symbols increases, the number of symbols actually having a value is very sparsely configured such that the complexity of a transmitter and a receiver does not increase, and thus restoration performance improves.

Abstract: The present disclosure relates to a 5G generation or pre-5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. The present disclosure relates to uplink transmission in a wireless communication system, and an operating method of a terminal includes: determining a second codebook for a reference signal, based on a first codebook for data; and transmitting at least one reference signal generated by using the second codebook, and at least one data signal generated by using the first codebook.

Abstract: The present prevent relates to a method of sparsifying a channel using beamforming in a wireless communication system, the method including inserting pilot symbols into resources allocated among resource elements constituting a time-frequency grid; calculating beamforming weights for sparsifying a beamformed time-domain channel; and beamforming frequency-domain channels of a plurality of antennas mapping the pilot symbols by using the beamforming weights.

Abstract: The present disclosure relates to a 5G or pre-5G communication system to be provided to support a higher data transmission rate beyond the 4G communication system, such as LTE. The present invention provides a method for estimating a downlink channel by a receiver in a wireless communication system, the method comprising: estimating the downlink channel on the basis of a reference signal to recover an information bit, and checking whether the information bit recovery has succeeded; and when the information bit recovery has not succeeded, selecting at least one of the received signals as a virtual reference signal on the basis of the accuracy of the data reconstructed at a related resource location and the correlation between the related resource location and a resource location related to the reference signal, and estimating the downlink channel on the basis of at least one virtual reference signal.

Abstract: The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate than in a 4G communication system such as LTE. The present disclosure relates to uplink transmission in a wireless communication system, and an operating method of a terminal includes mapping codes that are included in at least one codebook onto data symbols. and transmitting the data symbols spread by using the at least one codebook, and the data symbols are used for a base station to detect at least one active terminal including the terminal.

Abstract: The present disclosure relates to a 5G or pre-5G communication system to be provided to support a higher data transmission rate beyond the 4G communication system, such as LTE. The present invention provides a method for estimating a downlink channel by a receiver in a wireless communication system, the method comprising: estimating the downlink channel on the basis of a reference signal to recover an information bit, and checking whether the information bit recovery has succeeded; and when the information bit recovery has not succeeded, selecting at least one of the received signals as a virtual reference signal on the basis of the accuracy of the data reconstructed at a related resource location and the correlation between the related resource location and a resource location related to the reference signal, and estimating the downlink channel on the basis of at least one virtual reference signal.

Abstract: The present disclosure relates to a 5G generation or pre-5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. The present disclosure relates to uplink transmission in a wireless communication system, and an operating method of a terminal includes: determining a second codebook for a reference signal, based on a first codebook for data; and transmitting at least one reference signal generated by using the second codebook, and at least one data signal generated by using the first codebook.

Abstract: The present disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as long term evolution (LTE). The present disclosure relates to channel information feedback in a wireless communication system, and an operation method of a receiving node includes: determining compressed channel information based on an eigenvalue decomposition of a covariance matrix regarding a channel, and transmitting, to a transmitting node, a direction index and a magnitude index representing the compressed channel information. Herein, a dimension of the compressed channel information is lower than a dimension of channel information associated with the transmitting node. Also, the disclosure includes other embodiments, different from the above described embodiment.

Abstract: A method of receiving a signal by a receiver in a mobile communication system is provided. The method includes: receiving a reference signal from a transmitter; determining first channel information based on the received reference signal; receiving a data signal based on the first channel information; and determining second channel information based on the received data signal and the first channel information. Iterative channel estimation is performed to reduce channel estimation errors by determining errors of signals received from a turbo decoding unit and using symbol information as pilots even in subcarriers where the pilot signals are not transmitted, and to increase the accuracy of LLR calculation through an iteration process such as a detection and decoding process in comparison with the conventional technology, thereby increasing the reception performance of the turbo decoding unit and improving communication efficiency.

Abstract: Disclosed are a method and an apparatus for grouping antennas in a multiple-input multiple-output antenna system. The method of the present invention comprises the steps of: measuring a channel vector for a plurality of antennas of a base station; grouping channel coefficients of the channel vector in accordance with a plurality of antenna grouping patterns and determining grouped codebook vectors corresponding to the grouped channel coefficients; selecting one of the antenna grouping patterns using the grouped codebook vectors for the antenna grouping patterns; and feeding back, to the base station, a pattern index indicating the selected antenna grouping pattern and a codebook index indicating the grouped codebook vector corresponding to the selected antenna grouping pattern.