Reducing PAPR With Low Complexity for 4G and 5G Waveform Designs

Abstract

Partial transmit sequence (PTS) technique is considered as one of the efficient methods to reduce the high peak-to-average power ratio (PAPR) problem in 4G waveform design such as the orthogonal frequency division multiplexing (OFDM) systems. Filtered-OFDM (F-OFDM) is a new candidate in the 5G waveform development with maintaining a high level of commonality with legacy OFDM systems, but the high PAPR value is still a considerable problem because F-OFDM supports the orthogonal transmission. Although the PTS technique improves the PAPR reduction performance significantly, the high computational complexity level for optimizing the phases of the transmitting signal restricts this technique in practical applications. Therefore, the low computational complexity level of the PTS technique leads to the adoption of this technique for PAPR reduction in the multicarrier systems such as OFDM and F-OFDM. In this paper, a new low complexity algorithm (Gray-PF-PTS) by combining the Gray code and the left feedback shift register operation based on a specific mapping rule has been proposed. The numerical results indicate that the Gray-PF-PTS algorithm extensively reduces the computational complexity level without degradation the PAPR reduction performance compared with the conventional PTS method. Furthermore, the OFDM and F-OFDM systems based on the Gray-PF-PTS algorithm have been compared regarding the PAPR, bit error rate (BER), and power spectrum density (PSD) performances.

Keywords

• OFDM
• F-OFDM
• 4G
• 5G
• PAPR
• PTS