Methods, systems, and apparatuses are presented to transmit fragmented communication frames, such as fragmented ultra-wideband (UWB) frames. In some implementations, a communication frame may be divided into a plurality of fragments, and the fragments may be transmitted across a plurality of regulatory test intervals. E.g., each fragment may be transmitted within a mutually-exclusive regulatory test interval. In some implementations, each fragment may be constrained in time and/or transmission power, such that the total energy emitted during transmission of the fragment remains within a maximum energy limit defined for the regulatory test interval, e.g., by a regulatory entity. In some implementations, the sum of the energy emitted during transmission of two or more fragments may exceed the maximum energy limit defined for the regulatory test interval.