Print ISSN: 1811-9212

Online ISSN: 2617-3352

Keywords : Orthogonal Frequency Division Multiplexing (OFDM)


Mitigate PAPR Effect in Optical Orthogonal Frequency Division Multiplexing Using Companding Technique

Ali n. Kareem; Sinan M. Abdul Satar; Mohammed A. Husein

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2018, Volume 18, Issue 3, Pages 60-69

orthogonal frequency division multiplexing (OFDM) is emerging as
the leading technology for high data rates. The OFDM based on multicarrier
transmission that transforms a wideband channel into a group of thin-band
channels. The high peak to average power ratio (PAPR) considers the main
drawback factor in this system, so the companding technique modifies the
amplitude of OFDM signal to reduce this factor. The proposed A-law
companding technique has been implemented in intensity modulation/direct
detection optical orthogonal frequency division multiplexing (IM/DDOOFDM).
The proposed companding scheme guarantees the improved
performance in terms of bit error rate (BER) and quality factor (QF) while
reducing PAPR effectively and efficiently by modifying the amplitude of the
transmitted signals. Our results confirm that the suggested scheme exhibits a
good ability to reduce PAPR and a good BER performance based on the use the
A factor. At the complementary cumulative distribution function (CCDF) of 10-
3, the PAPR value of our proposed scheme is about 4.4 dB lower than those of
un-companded signal at best control factor used of A at 87.6, accordingly the
QF is 2.5 dB and the BER is 6.2×10-3 at a distance 900km without any
equalization technique or training sequence or any channel estimation.

PAPR Reduction in Coherent Optical OFDM System using Modified Sliding Norm Transformer

Liqaa A. Al-Hashime; Sinan M. Abdul Satar; Ghaida A. AL-Suhail

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2018, Volume 18, Issue 3, Pages 33-42

Orthogonal Frequency Division Multiplexing is one of the most
important multiple carrier modulation format, which has many applications in
wireless communication and optical communication. It is considered as an
excellent method for fast optical communication inferable from its high spectral
efficiency and its strength to path losses. Peak to average power ratio is
regarded as one of the main problems that are experienced by the optical
orthogonal frequency division multiplexing system, which directly affects the
characteristics of the system. The current paper proposes an efficient technique
to reduce Peak to Average Power Ratio by the modified Dursun’s method or the
so called modified discrete sliding norm transformer in coherent optical
orthogonal frequency division multiplexing system for the first time to the base
of our knowledge consequently. The proposed technique does not need to send
side information to the receiver; also, it does not degrade bandwidth. This
algorithm lessens Peak to Average Power Ratio in the optical coherent
Orthogonal Frequency Division Multiplexing system to about 4.15 dB at
complementary cumulative distribution function (CCDF) probability of 10-3 and
improves the system performance.