In the novel method for data transmission via a radio interface in a radio communications system, at least two data channels are assigned to one connection. Each data channel can be distinguished by an individual spread code. In addition to data symbols, midambles with known symbols are transmitted in a data channel. The number of midambles being used for the connection is less than the number of data channels. The method is particularly suitable for use in TD/CDMA 3^rd generation mobile radio networks.