Systems and techniques relating to repeated signal detection are described. A described technique includes receiving a signal including a first portion and a second portion, the first portion including a first received symbol and a second received symbol; detecting whether the first received symbol is repeated as the second received symbol using a maximum a posterior decision metric including a first component and a second component, the first component contributing to the decision metric in accordance with the first received symbol being repeated as the second received symbol, and the second component contributing to the decision metric in accordance with the first received symbol not being repeated as the second received symbol; determining a format based on whether or not the first received symbol was repeated; and processing the second portion of the signal in accordance with the format, as determined.