This document describes a simulator designed to analyze bit error rates using orthogonal frequency division multiplexing (OFDM) under different modulation schemes and channel conditions. The simulator was implemented in MATLAB and allows users to choose modulation types, channel types (AWGN, Rayleigh, Rician), and other parameters. It then generates plots of bit error rate versus signal-to-noise ratio for performance analysis. Screenshots of the user interface are provided along with sample output plots and discussion of the simulator design and capabilities.
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM )BhaSkar Nath
Principle of orthogonal frequency-division multiplexing (OFDM)
Optical transmitter for CO-OFDM
Optical spectral efficiency for CO-OFDM
Channel model for CO-OFDM
The channel model describes the behavior of communications systems, thus fundamentally determining the performance of the systems
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM )BhaSkar Nath
Principle of orthogonal frequency-division multiplexing (OFDM)
Optical transmitter for CO-OFDM
Optical spectral efficiency for CO-OFDM
Channel model for CO-OFDM
The channel model describes the behavior of communications systems, thus fundamentally determining the performance of the systems
OFDM allows tightly packed carriers to convey information orthogonally and with high bandwidth efficiency
Objectives Description:
Concepts
Basic idea
Introduction to OFDM
Implementation
Advantages and Drawbacks.
FDMA
Orthogonal frequency-division multiplexing (OFDM)
[1] is a method of encoding digital data on multiple carrier
frequencies. OFDM[1] has developed into a popular scheme
for wideband digital communication, whether wireless or
over copper wires, used in applications such as digital television
and audio broadcasting, DSL Internet access, wireless networks,
powerline networks, and 4G mobile communications. In the
Several wireless standards such as IEEE 802.11a[2] and
HiperLAN2[3].The orthogonality of the subcarriers is no longer
maintained which results in ICI (Inter carrier Interference)[4]
.ICI reduction techniques achieve a better SNR and BER in
OFDM at zero phase noise variance . This technique will use a
large number of closely spaced orthogonal subcarriers to avoid
phase noise. It provides high data rates with sufficient robustness
to radio channel damages. A major problem in OFDM is carrier
frequency offset error between the transmitted and received
signals. Due to this the orthogonality of the subcarriers is no
longer maintained which results in ICI (Inter carrier
Interference). In this paper, we used the ICI self-cancellation
technique and reduced the ICI and improved the BER and SNR
we are also calculate the SNR=15db and 20db at different phase
noise variance.
MIMO radar is introduced in presentation ,its advantage .future scope,research area.
MIMO radars represent a new generation of radars. In contrast to the traditional phased-array radar in which the transmit elements can transmit only the scaled versions of same signal, a MIMO radar allows the transmitters to transmit multiple signals. This waveform diversity offers enhanced flexibility in transmit beampattern synthesis which is an important area of MIMO radar signal processing
ESTIMATION OF CHANNEL IN OFDM WIRELESS CHANNEL USING LS AND MMSE TECHNIQUESIAEME Publication
In recent years with the increase in digital data communication, the need for high data rates with less information loss or distortion is being a continuous research area and new techniques are being invented in this area. Large amount of people are using the air interface for proper communication which also have a lot of drawbacks which include multipath fading, Inter symbol interference (ISI), Doppler shift etc..This paper is being presented on basis of channel estimation of wireless mobile OFDM channels using known pilot symbols.
PERFORMANCES OF ORTHOGONAL WAVELET DIVISION MULTIPLEX (OWDM) SYSTEM UNDER AWG...IJCNCJournal
Orthogonal Wavelet Division Multiplexing (OWDM) has been considered as an alternative of Orthogonal
Frequency Division Multiplexing (OFDM) in the recent years. OWDM has lower computational complexity
and higher flexibility compared to its OFDM counterpart. The core component of OWDM is wavelet.
Wavelet has been a much investigated and applied topic in digital image processing for a long time.
Recently, it has drawn considerable attention of the researchers working in communication field. In this
work we investigate the performances of OWDM under different channel conditions. We consider three
channel conditions namely Additive White Gaussian Noise (AWGN), Rayleigh, Ricean, and frequency
selective. We consider a number of wavelets namely Haar, Daubechies, Biorthogonal, Reverse
Biorthogonal, Coiflets, and Symlets in OWDM design. For system model we choose Digital Video
Broadcasting-Terrestrial (DVB-T). Originally DVB-T system was designed based on OFDM. In this work
we use OWDM instead. The simulation results show OWDM outperforms OFDM in terms of bit error rate
(BER), noise resiliency, and peak-to-average ration. The results also show that the Haar wavelet based
OWDM outperforms other wavelets based OWDM system under all three considered three channel
conditions.
OFDM allows tightly packed carriers to convey information orthogonally and with high bandwidth efficiency
Objectives Description:
Concepts
Basic idea
Introduction to OFDM
Implementation
Advantages and Drawbacks.
FDMA
Orthogonal frequency-division multiplexing (OFDM)
[1] is a method of encoding digital data on multiple carrier
frequencies. OFDM[1] has developed into a popular scheme
for wideband digital communication, whether wireless or
over copper wires, used in applications such as digital television
and audio broadcasting, DSL Internet access, wireless networks,
powerline networks, and 4G mobile communications. In the
Several wireless standards such as IEEE 802.11a[2] and
HiperLAN2[3].The orthogonality of the subcarriers is no longer
maintained which results in ICI (Inter carrier Interference)[4]
.ICI reduction techniques achieve a better SNR and BER in
OFDM at zero phase noise variance . This technique will use a
large number of closely spaced orthogonal subcarriers to avoid
phase noise. It provides high data rates with sufficient robustness
to radio channel damages. A major problem in OFDM is carrier
frequency offset error between the transmitted and received
signals. Due to this the orthogonality of the subcarriers is no
longer maintained which results in ICI (Inter carrier
Interference). In this paper, we used the ICI self-cancellation
technique and reduced the ICI and improved the BER and SNR
we are also calculate the SNR=15db and 20db at different phase
noise variance.
MIMO radar is introduced in presentation ,its advantage .future scope,research area.
MIMO radars represent a new generation of radars. In contrast to the traditional phased-array radar in which the transmit elements can transmit only the scaled versions of same signal, a MIMO radar allows the transmitters to transmit multiple signals. This waveform diversity offers enhanced flexibility in transmit beampattern synthesis which is an important area of MIMO radar signal processing
ESTIMATION OF CHANNEL IN OFDM WIRELESS CHANNEL USING LS AND MMSE TECHNIQUESIAEME Publication
In recent years with the increase in digital data communication, the need for high data rates with less information loss or distortion is being a continuous research area and new techniques are being invented in this area. Large amount of people are using the air interface for proper communication which also have a lot of drawbacks which include multipath fading, Inter symbol interference (ISI), Doppler shift etc..This paper is being presented on basis of channel estimation of wireless mobile OFDM channels using known pilot symbols.
PERFORMANCES OF ORTHOGONAL WAVELET DIVISION MULTIPLEX (OWDM) SYSTEM UNDER AWG...IJCNCJournal
Orthogonal Wavelet Division Multiplexing (OWDM) has been considered as an alternative of Orthogonal
Frequency Division Multiplexing (OFDM) in the recent years. OWDM has lower computational complexity
and higher flexibility compared to its OFDM counterpart. The core component of OWDM is wavelet.
Wavelet has been a much investigated and applied topic in digital image processing for a long time.
Recently, it has drawn considerable attention of the researchers working in communication field. In this
work we investigate the performances of OWDM under different channel conditions. We consider three
channel conditions namely Additive White Gaussian Noise (AWGN), Rayleigh, Ricean, and frequency
selective. We consider a number of wavelets namely Haar, Daubechies, Biorthogonal, Reverse
Biorthogonal, Coiflets, and Symlets in OWDM design. For system model we choose Digital Video
Broadcasting-Terrestrial (DVB-T). Originally DVB-T system was designed based on OFDM. In this work
we use OWDM instead. The simulation results show OWDM outperforms OFDM in terms of bit error rate
(BER), noise resiliency, and peak-to-average ration. The results also show that the Haar wavelet based
OWDM outperforms other wavelets based OWDM system under all three considered three channel
conditions.
Performance of OFDM System under Different Fading Channels and Channel CodingjournalBEEI
Orthogonal frequency division multiplexing (OFDM) is a type of multicarrier modulation (MCM) technique in which larger bandwidth is divided into parallel narrow bands each of which is modulated by different subcarriers. All the subcarriers are orthogonal to each other and hence it reduces the interference among various subcarriers. OFDM technique is an efficient modulation technique used in certain wired and wireless application.In a wireless communication channel, the transmitted signal can travel from transmitter to receiver over multiple reflective paths. This results to multipath fading which causes fluctuations in amplitude, phase and angle of arrival of the received signal. For example, the signal which is transmitted from BTS (base transceiver station) may suffer multiple reflections from the buildings nearby, before reaching the mobile station. Such multipath fading channels are classified into slow fading/fast fading and frequency-selective/flat fading channels. This paper discusses the performance of OFDM system using various fading channels and channel coding. The parameter which is known as Bit error rate (BER) is calculated under different fading channels (AWGN, Rayleigh and Rician) for different digital modulation (BPSK, QPSK and QAM) and Channel coding (linear/Cyclic coding). Matlab Simulink tool is used to calculate the BER parameter.
Error Rate Analysis of MIMO System Using V Blast Detection Technique in Fadin...IJERA Editor
Wireless communication system with multi- antenna arrays has been a field of intensive analysis on the last years. The appliance of multiple sending antennas and Receiving Antennas either side will considerably enhance the data rate and rate. The review of the performance limitations of MIMO system becomes vital since it will provide lot ideas in understanding and planning the important life MIMO systems. Vertical Bell Laboratories layered space Time (V-BLAST). The thought behind Multiple Input and Multiple Output system is that the signals on the transmitter antennas at one finish and also the receiver antennas at the opposite finish are correlative in such how that the performance (Bit Error Rate or BER) or the info rate (bits/sec) of the wireless communication system for every MIMO subscriber are improved. During this paper we tend to are proposing a technique that evaluates the performance of V-BLAST MIMO system in several thought of Rayleigh attenuation surroundings to urge higher performance of the system. In V- BLAST MIMO system a number of linear detection techniques will be used for interference cancellation. At this point we are using MMSE-IC for the same. Our expected system provide higher error rate performance with the used of matched filter at receiver aspect .The projected system compared within the presence of AWGN. Now matched filter applied on V- BLAST MIMO with MMSE-IC system in fading diversity surroundings.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
Abstract (11Bold) : — In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR. Keywords (11Bold) –64 QAM, BPSK, OFDM, PDF, SNR.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR
Performance evaluation of 4-quadrature amplitude modulation over orthogonal ...IJECEIAES
Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation (MCM) technique that divides the wide bandwidth into parallel narrow bands, each of which is modulated by orthogonal subcarriers. Currently, OFDM is a high-spectral efficiency modulation technique that is used in a variety of wired and wireless applications. The transmitted signal in a wireless communication channel spreads from transmitter to receiver through multiple reflective paths. This triggers multipath fading, which causes variations in the received signal's amplitude and phase. Slow/fast and frequency-selective/frequency-nonselective are the main types of multipath fading channels. Therefore, in this paper, we proposed new models for modeling multipath fading channels, such as the exponential fading channel and the Gamma fading channel. In addition, new bit-error-rate (BER) derivations have been derived. The performance of the OFDM system over proposed channel models has been evaluated using Monte-Carlo simulation and compared to the Rayleigh fading channel model. The obtained results via simulations show that the exponential fading channel at a rate parameter (λ=0.5) outperforms the Rayleigh fading channel by 6 dB for all values of Eb/No, while the Gamma fading channel at (α=2) outperforms the Rayleigh fading channel by 3 dB for all values of Eb/No.
Comparative performance analysis of different modulation techniques for papr ...IJCNCJournal
One of the most important multi-carrier tran
smission techniques used in the latest wireless com
munication
arena is known as Orthogonal Frequency Division Mul
tiplexing (OFDM). It has several characteristics
such as providing greater immunity to multipath fad
ing & impulse noise, eliminating Inter Symbol
Interference (ISI) & Inter Carrier Interference (IC
I) using a guard interval known as Cyclic Prefix (C
P). A
regular difficulty of OFDM signal is high peak to a
verage power ratio (PAPR) which is defined as the r
atio
of the peak power to the average power of OFDM Sign
al. An improved design of amplitude clipping &
filtering technique of us previously reduced signif
icant amount of PAPR with slightly increase bit err
or rate
(BER) compare to an existing method in case of Quad
rature Phase Shift Keying (QPSK) & Quadrature
Amplitude Modulation (QAM). This paper investigates
a comparative performance analysis of the differen
t
higher order modulation techniques on that design.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
MIMO-OFDM (Multi Input Multi Output- Orthogonal Frequency Division Multiplexing) system is very popular technique for mobile communication. We found that Ergodic channel capacity has some limitation in MIMO-OFDM system. So Ergodic channel capacity optimization is necessary to improve the performance of MIMO-OFDM System.
The several assets for high-speed data transmission over wireless uses the Orthogonal Frequency Division
Multiplexing (OFDM) as it is a multicarrier transmission scheme. A large number of narrow bandwidth carriers is
therefore adopted by the OFDM. Individually for an OFDM, each subcarrier is attenuated under the frequency-selective
and fast fading channel, therefore the resulting gain is high attenuation which leads to poor performance of all OFDM
subcarriers if the same fixed transmission scheme are used. Thus the main goal of the indicated paper is to grab an
understanding of the inequality between fixed & adaptive modulations schemes as the introduction of the adaptive
modulation. The need for the above system is to make use of the speaker's voice to check their character and control
approach to administrations, for example, voice dialing data administrations, voice send, and security control for secret
data. The performance of paperwork basically states that implementation of adaptive modulation is done into blocks of
adjacent subcarriers which is the result of dividing whole subcarriers. Therefore the equivalent modulation scheme which
is the calculation of average instantaneous signal to noise (SNR) is exercised to entire subcarriers of the equal block. The
OFDM system average bit error rate (BER) performance is observed here under fixed modulation and adaptive
modulation, and these modulation techniques are recorded by accepting the different inverse fast Fourier transforms
(IFFT) size and uncomplicated adaptive Quadrature amplitude modulation (QAM) strategy. The simulation in MATLAB
shows the results as the performance of fixed modulation is inferior to that of the BER performance of OFDM system
using adaptive modulation. The prospective adaptive modulation and coding Technique uses OFDM to manage the fixed
BER under changing the channel.
This report discusses the planning Associate in
nursing the implementation of an OFDM system
in several information module schemes like MQPSK,
M-QAM. First, a short introduction is
provided by explaining the background and the
specification of the project. Then the report deals
with the system model, every block of the OFDM
system is represented (IFFT, FFT, Cyclic prefix,
modulation / reception, Channel estimation, bit
error rate). System design is analyzed. The
transmission techniques, further because the
system parameters for transmission and reception
are explained well. Finally, the results are
provided.
satellite communication jntuh
Satellite Link Design: Basic Transmission Theory, System Noise Temperature, and G/T Ratio,
Design of Down Links, Up Link Design, Design Of Satellite Links For Specified C/N, System Design
Examples.
Multiple Access: Frequency Division Multiple Access (FDMA), Inter modulation, Calculation of C/N,
Time Division Multiple Access (TDMA), Frame Structure, Examples, Satellite Switched TDMA
Onboard Processing, DAMA, Code Division Multiple Access (CDMA), Spread Spectrum Transmission
and Reception.
1. Design and Implementation of a Simulator for the
Analysis of Bit Error rates by using Orthogonal
Frequency Division Multiplexing
Abhishek Datta1
, Rupam Chowdhury1
, Sudip Dogra1
,
Electronics & Communication Dept.
Meghnad Saha Inst. Of Technology
Kolkata,India
e-mail: abhi06548@yahoo.com
rupam_ece@rediffmail.com dogra_sudip@rediffmail.com
Subir Kumar Sarkar2
Electronics & Telecommunication Dept.
Jadavpur University
Kolkata,India
Abstract---Orthogonal Frequency Division Multiplexing
(OFDM) has become very popular for its advantages. The
researches are till going on for the development of OFDM. In
this paper we have described a new simulator that can per-
form the BER analysis using OFDM technology and generate
respective plots for bit errors vs signal energy (Eb/No) for
several modulation schemes & different noise effects in three
types of channels (namely AWGN, Rayleigh and Rician).
Index Terms---- BER, Fading, Multipath, Noise.
I. INTRODUCTION TO OFDM
OFDM has become very popular since its inception. This
is used in many communication systems . The performance
analysis of this system for various modulation schemes un-
der different noise channels is an important issue while
choosing this for communication . We have implemented a
simulator using MATLAB 7.3 that can calculate & plot the
graphs showing bit errors vs signal energy (Eb/No) . This
helps us in performance analysis of the system. This GUI
based simulator can take inputs ( channel type, modulation
scheme, guard interval ength etc) & plots the graphs show-
ing BER vs Eb/No . This simulator can be very useful for
practiceng engineers and researchers for simulating their
designed systems with OFDM. The designed simulateor is
very user friendly. Our paper is organized as follows: In
section II we have described OFDM in brief. In section III
we have described various channel effects. In section IV we
have described our designed simulator. We concluded with
section IV.
II. OFDM IN BRIEF
OFDM is one of the dominant techniques of present day
wireless communication and also for future usage in mo-
bile industries. The key requirements for future mobile
communications include much higher peak data rate,
spectrum efficiency, and user capacity in high mobility en-
vironments.It is necessary to notice that the spectrum effi-
ciency advantages of OFDM are mainly achieved at an op-
eration point of relative high SNR. This is a quite different
from CDMA, which is mostly interference limited. Thus
severe problem arises with the high frequency reuse factor
of CDMA which may not be available for OFDM tech-
niques. OFDM is a kind of Multi Carrier Transmission sys-
tem where a single data stream is transmitted over a number
of subcarriers.
A. Properties of OFDM spectrum—
1. Each sub carrier in an OFDM spectrum has exactly an
integer number of cycles in the interval and the numbers of
cycles between adjacent subcarriers differ by exactly one.
2. Flexible bandwidth allocations are easily supported by
OFDM, at least from a baseband perspective, by varying
the number of OFDM subcarriers used for transmission.
B. OFDM Signal Representation---
C. OFDM—Advantage---
It increases the robustness against narrow band interfe-
rence, combat impulsive noise & multipath distortion. ICI
and ISI removed by orthogonal property and guard interval.
Efficient usage of channel bandwidth. Almost 50% band-
width is saved in case of OFDM.
Figure 1: Bandwidth saved using OFDM
∑
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i
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c etS i π
2. III. DIFFERENT CHANNEL EFFECTS
A. Additive White Gaussian Noise (AWGN) channel—
This channel model is one in which the information is given
a single impairment: a linear addition of wideband or white
noise with a constant spectral density (expressed as watts
per hertz of bandwidth) and a Gaussian distribution of noise
samples. The model does not account for the phenomena of
fading, frequency selectivity, interference, nonlinearity or
dispersion. Wideband Gaussian noise comes from many
natural sources, such as the thermal vibrations of atoms in
antennas (referred to as thermal noise or Johnson-Nyquist
noise), shot noise, black body radiation from the earth and
This channel model is one in which the information is given
a single impairment: a linear addition of wideband or white
noise with a constant spectral density (expressed as watts
per other warm objects, and from celestial sources such as
the Sun.
B. Multipath Rayleigh Fading channel---
In electromagnetic wave propagation, phase-interference
fading is caused by multipath, which may be approximated
by the Rayleigh distribution.
C. Multipath—
The propagation phenomenon resulting in radio signals
reaching the receiving antenna by two or more paths. Caus-
es of multipath include atmospheric ducting, ionospheric
reflection and refraction, and reflection from terrestrial ob-
jects, such as mountains and buildings. The effects of mul-
tipath include constructive and destructive interference, and
phase shifting of the signal.
The Rayleigh probability density function is
, For
D. Rician channel—
The Ricean distribution is given by
The parameter A denotes the peak amplitude of the domi-
nant signal and I0 (•) is a modified form of Bessel function
of the first kind and zero-order. The Ricean distribution is
often described in terms of a parameter K which is defined
as the ratio between the deterministic signal power and the
variance of the multipath. It is given by K= A2/ (2σ2) or, in
terms of dB
Figure 2: PDF of Ricean distributions:
K = – ∞ dB (Rayleigh) and K=6 dB. For K >> 1, the Ricean
pdf is approximately Gaussian about the mean.The parame-
ter K is known as the Ricean factor and completely speci-
fies the Ricean distribution.
As A → 0, K → –∞ dB, and also as the dominant path de-
creases in amplitude, the Ricean distribution degenerates to
a Rayleigh distribution.
IV. DESCRIPTION OF OUR SIMULATOR
We have designed a simulator to simulate the signal trans-
mission using OFDM technique and to obtain the variation
of BER with respect to SNR(Eb/N0). How much SNR is
required to achieve a particular BER, , can be obtained from
those curves. To make our simulator more user friendly we
have designed it in GUI (Graphical User Interface). Here
the input file is a random data. The user has the flexibility
to choose the modulation technique like BPSK, QPSK,
16PSK, 64PSK, QAM etc. Under the different modulation
technique and under the different environment like AWGN
environment, Rayleigh fading environment, the user can
simulate it and can get the desired output i.e. BER Vs SNR
curve and can obtain the relationship between the two pa-
rameters. The steps required to simulate the OFDM signals
in the simulator, a few screen shots are given below.
3. Figure 3: A screen shot of our simulator for user input for channel selec-
tion (The help window is displayed also)
In the simulator, for proper simulation, the user has to set
the input parameters first like symbol rate, FFT length,
guard interval length etc. Based on the set parameters, the
simulator simulate the OFDM signals under the selected
modulation technique and provide the modulation curves
that are shown in figures of BER analysis for AWGN, Ray-
leigh and Ricean channel.
The simulator is totally designed upon MATLAB platform
and works on auto-generated codes that makes up the GUI,
it is necessary to run the whole project from MATLAB
command window itself.
All the screens apperar with help windows. When the
mouse pointer is placed on any input box , relevant help
file is displayed automatically. Even if some mistake hap-
pens during input of data, warning message comes.
Figure 4 : A screen of our simulator for modulation type,symbol rate,
guard interval input.
The default parameters those have been used in our simu-
lator are shown in table 1.
Table 1: Default parameters used in simulation
Simulation Results ---
Since we have made use of the AWGN, Rayleigh and
Ricean fading channels, examples are provided for every
modulation scheme used for each channel.
All the figures give us the relation of Bit-Error rate
against the Signal to Noise power (Eb/No). A feature that
has been added to the plots in order to make things more
versatile and user-friendly is the provision of display of the
parameter values on the graph itself. In this way, we can
change values and compare the minute changes that occur
in the corresponding plots. The user interface for the simu-
lator keeps provision for such changes which a user can
make within specified ranges, from among the different
options for parameters mentioned in the interface.
Fig 5 : BER analysis for AWGN channel
Subcarriers 52
FFT/IFFT 64 point
Symbol time 4 µs
Guard time 800 ns
Modulation BPSK, QPSK,16- QAM,64-QAM
Coding rates 1/2, 3/4, 2/3
Bit rates 6,12,18,24,36,48,54 Mbps
Channel spacing 20 MHz
4. Fig 6 : BER analysis for Rayleigh Fading channel
Fig 7 : BER analysis for Rician Fading channel
Since our topic of OFDM simulation is a vast one, we have
concentrated on the findings of BER against Signal-Noise
ration only. There are many other data error rates through
transmission channels, like Symbol Error rate (SER), Mu-
tual information loss against SNR, Mean Square error
(MSE) of channel estimator etc which also prove to be
much helpful in gathering data transmission information.
V. CONCLUSION
In this paper we have described OFDM simulator with
changeable inputs. The design of such simulators for
OFDM-CDMA, COFDM , Mc-CDMA etc will also be
beneficial for the students and researchers. We are trying to
improvise upon this simulator, which will be much more
functional in obtaining any characteristic curves of several
other digital modulation techniques and will also be more
user friendly. Simulation therefore would be more unified.
ACKNOWLEDGEMENT
The design of such simulators for OFDM-CDMA,
COFDM, Mc-CDMA etc will be beneficial for the students
and researchers. The project , in itself, an introduction to
the recent technological development in mobile communi-
cations which has lately come to use. In order to gather as
much information as we could, we needed to consult lots of
texts on OFDM technology along with several articles on
3G-4G concepts. Last but not the least, Internet had been a
great guide for us; a bulk of web pages which were huge
sources to our knowledge. We have been under the guide of
our departmental H.O.D. who has also assisted us whole-
heartedly. We devoted most of the time in order to make it a
grand success.
REFERENCES
A few references have been enlisted herein, at the end of the
4-page manuscript. These are some of the books, articles,
web pages and videos that we have taken the help of , for
the successful completion of the project by Matlab pro-
gramming and simulation. Internet has been the greatest
guide to us and thereby bulks of web pages and links have
been stated below. The whole concept of recent wireless
developments and OFDM technology had been clarified
from those web links. Moreover, learning MATLAB was
also a mammoth task and we had actually consulted refer-
ence books to get ourselves accustomed with MATLAB
new versions and have found out that the software itself was
a big guide to us, all through the project.
[1] “OFDM for wireless multimedia communications” Richard Van Nee,
Ramjee Prasad
[2] “Simulation and software radio for mobile communications “-Hiroshi
Harada, Ramjee Prasad
[3] “The suitability of OFDM as a modulation technique for wireless
telecommunications, with a CDMA comparison” by Eric Lawrey
[4] Mastering MATLAB 7 - Duane C Hanselman, Bruce L Littlefield
[5] MATLAB link: http://blinkdagger.com/matlab/matlab-gui-querying-
the-user-for-input
[6] Link: dsp.ucsd.edu/students/present.../mik/matlabgui/outline.html
[7] The performance of OFDM in Mobile Radio Channel by Teddy
Purnamirza
[8] Link: www.intelligent-systems.info / classes / ee509/ gui.html
[9] Link: video.filestube.com/m/matlab+gui
[10] Link: en.wikipedia.org/Orthogonal_frequency-division_multiplexing
[11] Link: rfdesign.com/next_generation_wireless/ofdm
[12] Robertson, P. Kaiser, S. "The effects of Doppler spreads in
OFDM (A) mobile radio systems", Vehicular Technology
Conference, 1999 .VTC 1999 - Fall. IEEE VTS