Systems, methods, and other embodiments associated with preamble detection based on repeated preamble codes are described. According to one embodiment, an apparatus is provided that wirelessly receives a signal and calculates a differential output corresponding to a multiplication of the signal and a delayed version of the signal. A cross correlation is performed between the differential output and a known preamble pattern to produce a cross correlation output. One or more peaks are detected in the cross correlation. The detected peaks are used in subsequent processing to detect the known preamble pattern in the wirelessly received signal.