Effect of partition length variability on the performance of adjacent partitioing PTS in papr reduction of OFDM systems

Peak-to-Average Power Ratio (PAPR) reduction is an attractive research topic among the OFDM transmission research communities. Partial Transmit Sequence (PTS) has been a promising candidate out of the proposed PAPR reduction techniques without any distortion. In any PTS system, partitioning of the OFDM frame into disjoint sub-blocks is a crucial step. Adjacent partitioning (AP) is a rather simple partitioning scheme achieving attractive PAPR reduction performance. In this paper, we investigate effects of the length variability of disjoint sub-blocks on AP based PTS systems. In order to compare performance of variable length adjacent partitioning with the ordinary PTS scheme, we simulated other partitioning schemes, namely, interleaved, pseudorandom and fixed length adjacent partitioning for various types of modulation. Simulation results showed that the variable length adjacent partitioning is better than interleaved partitioning. However, it has worse PAPR reduction performance compared to the traditional adjacent and pseudorandom techniques.

I. Introduction

Orthogonal frequency division multiplexing (OFDM) is an attractive technology due to the immunity effect of frequency selective fading channel for high rate data transmission and it has potential applications in broadband wireless communication systems [1]. OFDM has been adopted in different application systems such as wireless LANs and digital audio/video broadcasting systems [2]. However, one main drawback is the high peak-to-average power ratio (PAPR) of OFDM transmitted signals than single carrier signal because OFDM signal in time domain is the sum of many narrowband signals [3]. Due to power amplifier nonlinearity the high PAPR can lead out-of-band radiation and inter-modulation. To face the problem, the transmission amplifier must work within its linear region to prevent the degradation of the bit error rate (BER) and spectral distortion. High linearity usually means large power dissipation and low efficiency, which is expensive for use in portable wireless applications [4].