Various examples are provided for OOB interference and/or PAPR reduction in OFDM systems. In one example, a method includes generating a suppressing signal using channel state information (CSI) of a communication channel, where the length of the suppressing signal equals that of the OFDM symbol including a cyclic prefix (CP) and data portion; combining the OFDM symbol and the suppressing signal to generate a transmission signal, where the length of the suppressing signal is aligned with the length of the OFDM symbol; and communicating the transmission signal via the communication channel, which reduces and substantially aligns the length of the suppressing signal with a length of the CP at a receiving device. The CP and suppressing signal can be removed from the transmitted signal at the receiver using a CP removal matrix. In another example, a transmitting device includes OFDM encoding, signal suppression, combining circuitry to generate the transmission signal.