Journal of Theoretical and Applied Information Technology
30
th
June 2018. Vol.96. No 12
© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
3791
SENDING IMAGE IN NOISY CHANNEL USING
ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING
SCHEME
1*
GHASSAN MUSLIM HASSAN,
2
KHAIRUL AZMI ABU BAKAR,
3
MOHD ROSMADI MOKHTAR
1, 2, 3
Faculty of Information Science & Technology, University Kebangsaan
Malaysia (UKM), Malaysia
*
Computer Dep., College of Science, Al-Mustansiriyah University, Baghdad, Iraq
E-mail:
1
gmhalsaddi@siswa.ukm.edu.my,
1
gmhalsaddi@yahoo.com,
2
khairul.azmi@ukm.edu.my,
3
mrm@ukm.edu.my
ABSTRACT
Orthogonal frequency division multiplexing (OFDM) is dependable in data transmission with high speed by
the benefit of its robustness to multi-path fading, high data rate, and high spectral efficiency. OFDM is a
multi-carrier modulation scheme. Synchronization is the major problems of the OFDM system. In this
research, the power consumption was considering through a noisy channel when an image was transmitted
in the OFDM system. To support the work, many features were tested such as minimizing the complexity
with fast Fourier transforms/inverse fast Fourier transform (FFT/IFFT). The size of bandwidth (BW) play
the main role and how its effect on the transmission and how its related to the FFT size (Nfft). The
modulation type was also tested to see which one is the best for image transmitted. These types are phase
shift keying (PSK) and quadrature amplitude modulation (QAM). In addition, signal to noise ratio (SNR) is
one of the performances in OFDM system and consider one of the factors which wireless communication
depends on related with bit error rate (BER). Another drawback of the OFDM system was Peak-to- average
power ratio (PAPR), therefore, the effect of Nfft on the PAPR has been tested with simulation results in
which additive white Gaussian noise (AWGN) had been used in the MATLAB simulation.
Keywords: Bit Error Rate, Fast Fourier Transform, Orthogonal frequency division multiplexing, Peak-to-
Average power ratio, Signal-to-Noise Ratio.
1. INTRODUCTION
This By the improvement of the hardware,
digital signal processing made orthogonal
frequency division multiplexing (OFDM) an
accurate decision for wireless systems [1]. Latterly,
OFDM emerged as a key candidate for high-data-
rate applications. Now, it's used for digital video
broadcasting (DVB), digital audio broadcasting
(DAB), wireless local area networks, fourth-
generation cellular systems, and WiMAX [2].
The principle of OFDM system is as
follows; The transmitted signal (data) is divided
into many smaller sub-signals, transmit these sub-
signal to receiver in a simultaneous manner with
various frequencies. The main bandwidth (BW) is
also divided into many subbabnds, therefore, the
signal crosstalk was reduced using OFDM. Due to
the channel transmission errors, the data are either
missing or incorrect when an image had been
transmitted [3]. It’s a challenging task when an
image was transmitted over a fading channels
without despised the perceptual quality and while
mitigating the power consumption in many fields.
Re-sending the lost packets every time in numerous
applications, such as VB [9], is likewise
impractical. Many of OFDM’s benefits are its
facility to deal with severe channel conditions with
no need for a complex equalization filter. In
OFDM, a huge number of orthogonal, overlapping,
and narrow band subcarriers are transmitted in
parallel and used in digital communication [5], in
which the spectra of these sub-carriers are closely
spaced and overlapped to achieve high BW
efficiency, therefore, the sub-carriers BW became
small when compared with the coherence BW of
the channel [4]. OFDM allows digital data,
including image data, to be efficient and reliably
transmitted in multipath environments by lowering