A New Technique for PAPR Reduction in OFDM System

Abstract

Orthogonal frequency division multiplexing (OFDM) is an attractive technique for
modern wireless communication. One major drawback of orthogonal frequency division
multiplexing schemes is the high peak to average power ratio (PAPR) of the output signal.
Selecting mapping (SLM) and partial transmit sequences (PTS) are two important techniques
for reducing PAPR, but they need to transmit side information to indicate how the transmitter
generates the signals. In this paper, we proposed an efficient technique to reduce PAPR in
OFDM system. For this technique, circular shifter used to produce K cyclic sequences from
the same information sequence. These sequences XOR with K randomly generated keys, the
same keys used in receiver side to detect data. The sequence with the lowest PAPR among K
sequences is chosen for transmission. Side Information (SI) is coded using Hamming code
and embedded into the information sequence. Computer simulation tests have been applied on
BPSK and N= 64 subcarriers OFDM system with the proposed method. Moreover, this
system will be evaluated under the effect of AWGN channel. The results exhibit the ability of
such technique to reduce the PAPR without major effect on the system performance as
compared with the conventional OFDM technique. The PAPR of OFDM signal is further
reduced by 4–5 dB by this technique