Wireless communications systems may configure a subset of allocated resources (e.g., one or more resource elements (REs) of one or more allocated resource blocks (RBs)) as peak reduction tones (PRTs) for a peak-cancelation signal. For instance, wireless communications systems may configure a fixed PRT allocation based on a Costas array. In some examples, each column of a Costas array may correspond to a RB of a set of allocated resources. A transmitting device may thus identify one or more PRT REs based on the Costas array and a mapping of allocated RBs to the columns of the Costas array. For instance, a transmitting device may identify a pattern of PRT REs to use for a peak-cancellation signal based at least in part on a configured Costas array (e.g., where the peak-cancellation signal may reduce peaks of a corresponding data signal to ultimately reduce peak-to-average power ratio (PAPR) of a transmission).