Intermodulation compensation using code reversal technique for orthogonal multi-carrier modulation

Since an orthogonal multi-carrier signal has large peak power. intermodulation distortion occurs due to the non-linearity of the power amplifier. This distortion severely deteriorates the performance of the multi-carrier system. Especially when carriers ate modulated by information bits which produce the same phase shift or the alternative phase shift. the modulated signal has maximum peak power at the input of the amplifier. In order to avoid these phase shifts (code sequences), we propose a code reversal technique which suppresses the maximum peak power of multi-carrier signals for intermodulation compensation, This method utilizes the reversal codes which are added to the original information bits. We also show the effectiveness of the code reversal technique combined with error correction coding and examine the optimum operating point of the amplifier.