A method for duplex telecommunication connection in radio connections is based on a frame-structured interactive communication and a radio system where the frame-structured interactive communication is performed in the radio connections. A means is provided for improving the use of channel resources in implementation of interactive telecommunication connection by providing an FDD connection with one or more TDD dimensions. A full-duplex frequency band is time-duplexed into two or more sub-bands in which interactive communication takes place substantially independently. Transmissions in different transmission directions in each sub-band occur at different times, but simultaneous transmission can occur in different sub-bands in different transmission directions. The message is received entirely in one transmission direction before it needs to be responded to in another transmission direction in a particular sub-band. The frequency band is utilized effectively for communication because transmission can be performed simultaneously in different sub-bands in the reverse transmission directions.