A New Technique for PAPR Reduction in OFDM System


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.