Novel Precoding Based PAPR Reduction Schemes for Localized OFDMA Uplink of LTE-A

Abstract

High Peak to Average Power Ratio (PAPR) reduction is still a major challenge in Orthogonal Frequency Division Multiple Access (OFDMA) systems. The subcarrier mapping in OFDMA can be done in two modes, Localized mode and Distributed mode. The Localized mode is more suitable for the practical implementations than the Distributed mode due to its low sensitivity against the imperfect power control, phase noise and Inter Carrier Interference (ICI). In this paper, we propose two novel precoding based Multi-Carrier (MC) Multiple Access (MA) techniques for PAPR reduction, ZadoffChu precoding based Localized-OFDMA (L-OFDMA) technique and Generalized Chirp Like (GCL) precoding based L-OFDMA technique for L-OFDMA uplink systems of upcoming Long Term Evaluation-Advanced (LTE-A) system. These techniques are based on precoding the constellation symbols with Zadoff-Chu precoder and GCL precoder. The proposed techniques can reduce PAPR up to 6.5dB for L-OFDMA. It is noticeable from the computer simulation results, that the PAPR of our proposed precoding based MC systems have approximately equal PAPR as compared to the PAPR of competing technology called Localized Single Carrier Frequency Division Multiple Access SC-FDMA (LFDMA) system. LFDMA is implemented in release 8 of Long Term Evaluation (LTE). Additionally, these precoding based PAPR reduction techniques also takes the advantage of the frequency variations of the communication channel and can also offer substantial performance gain in fading multipath channels