Current frame structures in Long-Term Evolution (LTE) and New Radio (NR) place some restrictions on the symbols transmitted in the frame, e.g. restrictions related to the duration of each symbol. Embodiments are disclosed in which multi-carrier symbols and/or single-carrier symbol blocks have configurable parameters, such as configurable length and/or configurable location, thereby allowing for more flexibility in the scheduling and transmission of the symbols and/or symbol blocks. Some embodiments aim to implement the configurable parameters in a way that tries to reduce signaling overhead.