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: A method for selecting a Multiple-Input Multiple-Output (MIMO) mode based on energy efficiency and selecting an antenna subset to be used in a communication, in a wireless communication system using a multi-user massive multi-antenna is provided. The method selects an antenna subset capable of minimizing transmission power without using all antennas, based on power consumed by an Radio Frequency (RF) circuit as well as the transmission power. The method further includes selecting a mobile station to which the signal is to be transmitted, selecting a multi-antenna technique based on power consumption of all antennas, selecting an antenna subset to transmit the signal to the mobile station among all the antennas, and transmitting the signal to the mobile station by using the antenna subset.

Abstract: A method for selecting a Multiple-Input Multiple-Output (MIMO) mode based on energy efficiency and selecting an antenna subset to be used in a communication, in a wireless communication system using a multi-user massive multi-antenna is provided. The method selects an antenna subset capable of minimizing transmission power without using all antennas, based on power consumed by an Radio Frequency (RF) circuit as well as the transmission power. The method further includes selecting a mobile station to which the signal is to be transmitted, selecting a multi-antenna technique based on power consumption of all antennas, selecting an antenna subset to transmit the signal to the mobile station among all the antennas, and transmitting the signal to the mobile station by using the antenna subset.

Abstract: A method for selecting a Multiple-Input Multiple-Output (MIMO) mode based on energy efficiency and selecting an antenna subset to be used in a communication, in a wireless communication system using a multi-user massive multi-antenna is provided. The method selects an antenna subset capable of minimizing transmission power without using all antennas, based on power consumed by an Radio Frequency (RF) circuit as well as the transmission power. The method further includes selecting a mobile station to which the signal is to be transmitted, selecting a multi-antenna technique based on power consumption of all antennas, selecting an antenna subset to transmit the signal to the mobile station among all the antennas, and transmitting the signal to the mobile station by using the antenna subset.

Abstract: A method for selecting a Multiple-Input Multiple-Output (MIMO) mode based on energy efficiency and selecting an antenna subset to be used in a communication, in a wireless communication system using a multi-user massive multi-antenna is provided. The method selects an antenna subset capable of minimizing transmission power without using all antennas, based on power consumed by an Radio Frequency (RF) circuit as well as the transmission power. The method further includes selecting a mobile station to which the signal is to be transmitted, selecting a multi-antenna technique based on power consumption of all antennas, selecting an antenna subset to transmit the signal to the mobile station among all the antennas, and transmitting the signal to the mobile station by using the antenna subset.