Base station and User Equipment (UE) and methods to be performed therein for communication using a dynamic transmission parameter. The method to be performed in a base station comprises scheduling of transmission resources to a UE in an OFDM symbol associated with a dynamic parameter value. The base station is assumed to be associated with a carrier where a radio frame comprises at least one OFDM symbol associated with a fixed parameter value and at least one OFDM symbol associated with a dynamic parameter value, where the parameter is a cyclic prefix, CP, or a subcarrier spacing, Δf. The method further comprises determining a value of the parameter based on a characteristic of a radio link associated with the UE, and applying the determined value of the parameter when communicating with the UE in the scheduled transmission resources.