Enhanced PAPR in OFDM without Deteriorating BER Performance

Spyridon K. Chronopoulos, Giorgos Tatsis, Vasilis Raptis, Panos Kostarakis

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DOI: 10.4236/ijcns.2011.43020                

Abstract

Orthogonal frequency division multiplexing (OFDM) is vastly used in wireless networks. Its superiority relies on the fact that information can be split in large amount of frequencies. Each frequency is called information subcarrier. OFDM exhibits excellent annotation in channel fades and interferers as only a few subcarriers can be affected and consequently a small part of the original data stream can be lost. Orthogonality between frequencies ensures better spectrum management and obviates the danger of intersymbol interference. However, an essential problem exists. OFDM systems have high peak to average power ratio. This implies large fluctuations in signal power, ending up in increasing complexity of ADCs and DACs. Also, power amplifiers must work in a larger linear dynamic region. In this paper we present two new techniques for reducing Peak to Average Power Ratio (PAPR), that can be added in any OFDM system and we compare them with other existing schemes.

Keywords

OFDM, Convolutional Encoding, QPSK, Zero padding, IFFT, Cyclic Prefix, ISI, PAPR, Soft Reduction, μ-Law Algorithm, Clipping Ratio (CR), Peak Ratio (PR), BER, CCDF, μLSR, μLaCP

Conflicts of Interest

The authors declare no conflicts of interest.

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