PAPR Reduction in OFDM Systems Using Hybrid Zadoff-Chu Transform Precoding and Partial Transmit Sequence

Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation (MCM) scheme that plays a significant role in digital wireless communication. As a result of its high data rate capability and immunity to multipath fading effect, among others, OFDM remains an ideal technology for 5G communication systems and beyond. Unfortunately, a major drawback of this technology is the high peak-to-average power ratio (PAPR). Nevertheless, many techniques for reducing PAPR have been proposed in the past to address this problem. However, all the techniques previously used have limitations such as high computational complexity, data rate loss, high signal distortion, increase in bandwidth, increase in transmit power, and memory requirements. In this paper, a hybrid technique that combines Zadoff-Chu Transform (ZCT) precoding and Partial Transmit Sequence (PTS) for reducing high PAPR in OFDM signals is presented. To reduce the data rate loss and computational complexity in PTS when a large subblock is used, a Zadoff-Chu precoding is applied to OFDM symbols to precode the symbol before applying PTS with a fewer number of subblocks. An OFDM model was developed where ZCT and PTS techniques were implemented. The performance of the hybrid model was analyzed using Power Spectral Density (PSD), Complementary Cumulative Distribution Function (CCDF), and Bit Error Rate (BER). The simulation result indicates that the hybrid ZCT-PTS provides a better result than using either Zadoff-Chu precoding technique or Partial Transmit Sequence technique separately. A PAPR of 4.2 dB and BER of 3dB is achieved for hybrid ZCT-PTS. The hybrid technique provides a better system performance when compared with Conventional OFDM systems.