A radio system for a wireless node (12, 14) in a wireless communications system, comprising: • a first radio unit comprising: - a transmitter; - a receiver; - an antenna; and - a switching circuitry adapted to couple either an output of the transmitter of the first radio unit or an input of the receiver of the first radio unit to the antenna of the first radio unit; • a second radio unit comprising: - a transmitter; - a receiver; - an antenna; and - a switching circuitry adapted to couple either an output of the transmitter of the second radio unit or an input of the receiver of the second radio unit to the antenna of the second radio unit; and • a controller, wherein the radio system is configured to have a full-duplex mode of operation in which the radio system operates to simultaneously transmit and receive on a same frequency channel, and a half-duplex mode of operation in which the radio system operates to transmit and receive on the same frequency channel at different times, characterized in that the controller is configured to select between the full duplex mode of operation and the half-duplex mode of operation and is configured to select the half-duplex mode for one or more CSI measurements, the selection effected by the selective coupling of the transmitter and the receiver of both the first and the second radio units (66, 68) to the antenna (74, 92) of the corresponding first and second radio unit (66, 68) by the switching circuitry (76, 94) of the corresponding first and second radio unit (66,68). • a first radio unit comprising: - a transmitter; - a receiver; - an antenna; and - a switching circuitry adapted to couple either an output of the transmitter of the first radio unit or an input of the receiver of the first radio unit to the antenna of the first radio unit; - a transmitter; - a receiver; - an antenna; and - a switching circuitry adapted to couple either an output of the transmitter of the first radio unit or an input of the receiver of the first radio unit to the antenna of the first radio unit; • a second radio unit comprising: - a transmitter; - a receiver; - an antenna; and - a switching circuitry adapted to couple either an output of the transmitter of the second radio unit or an input of the receiver of the second radio unit to the antenna of the second radio unit; and - a transmitter; - a receiver; - an antenna; and - a switching circuitry adapted to couple either an output of the transmitter of the second radio unit or an input of the receiver of the second radio unit to the antenna of the second radio unit; and • a controller, wherein the radio system is configured to have a full-duplex mode of operation in which the radio system operates to simultaneously transmit and receive on a same frequency channel, and a half-duplex mode of operation in which the radio system operates to transmit and receive on the same frequency channel at different times, characterized in that the controller is configured to select between the full duplex mode of operation and the half-duplex mode of operation and is configured to select the half-duplex mode for one or more CSI measurements, the selection effected by the selective coupling of the transmitter and the receiver of both the first and the second radio units (66, 68) to the antenna (74, 92) of the corresponding first and second radio unit (66, 68) by the switching circuitry (76, 94) of the corresponding first and second radio unit (66,68). wherein the radio system is configured to have a full-duplex mode of operation in which the radio system operates to simultaneously transmit and receive on a same frequency channel, and a half-duplex mode of operation in which the radio system operates to transmit and receive on the same frequency channel at different times, characterized in that the controller is configured to select between the full duplex mode of operation and the half-duplex mode of operation and is configured to select the half-duplex mode for one or more CSI measurements, the selection effected by the selective coupling of the transmitter and the receiver of both the first and the second radio units (66, 68) to the antenna (74, 92) of the corresponding first and second radio unit (66, 68) by the switching circuitry (76, 94) of the corresponding first and second radio unit (66,68).