A method of transmitting data by a terminal device operating in a wireless communications system comprising a non-terrestrial network access node and the terminal device, comprises the terminal device receiving an indication of an initial value of a set of one or more communications parameters for transmitting radio signals carrying the data, and modelling a state of a communications channel from the terminal device to a non-terrestrial network access node, in which a link adaptation procedure is used to select a revised value of the set of the one or more communications parameters with respect to the initial value of the set of the one or more communications parameters for the modelled channel state, and the method includes adapting the value of the set of the one or more communications parameters according to the revised value.