In distributed mapping, the DFT outputs of the input data are assigned to subcarriers over the entire bandwidth non-continuously, resulting in zero amplitude for the remaining subcarriers. A special case of distributed SC-FDMA is called interleaved SC-FDMA (IFDMA), where the occupied subcarriers are equally spaced over the entire bandwidth.
In distributed mapping, DFT outputs from input data are assigned to subcarriers across the entire bandwidth intermittently, leaving the remaining subcarriers with zero amplitude. A specific type of distributed SC-FDMA is interleaved SC-FDMA (IFDMA), where occupied subcarriers are evenly spaced throughout the bandwidth.