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

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, Zadoff-Chu precoding based Localized-OFDMA (LOFDMA)
technique and Generalized Chirp Like (GCL)
precoding based L-OFDMA technique for L-OFDMA uplink
systems of upcoming Long Term Evaluation-Advanced (LTEA)
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.