An apparatus and method for transmitting data with conditional zero padding is provided. In accordance with an embodiment of the disclosure, a transmitter transmits data to a receiver by transmitting symbols such that each symbol is preceded by a cyclic prefix of a fixed length and the symbol conditionally includes enough zero padding to avoid ISI (Inter-Symbol Interference) between consecutive symbols. In some implementations, if the fixed length for cyclic prefixes is long enough to avoid ISI between consecutive symbols, then the symbols may omit zero padding. Otherwise, the symbols may include enough zero padding to avoid ISI between consecutive symbols. The zero padding may be zero tail or zero head.