A method by a user equipment (UE) is described. The method includes receiving a first physical signal, determining a first physical structure based on information in the first physical signal, and determining resource elements based on the first physical structure. A first set of subcarriers with first subcarrier spacing which is integer multiple or integer sub-multiple of second subcarrier spacing are mapped such that in addition to a slot boundary one or more of starting positions or ending positions of first subcarriers with the first subcarrier spacing in a first set of OFDM symbols are aligned with one or more of starting positions or ending positions of second subcarriers with the second subcarrier spacing in a second set of OFDM symbols.