PAPR Reduction in OFDM system Using Tone Reservation Technique

ISSN 2249-6343 

International Journal of Computer Technology and Electronics Engineering (IJCTEE) 

Volume 2, Issue 4, August 2012 

PAPR Reduction in OFDM system Using Tone 

Reservation Technique 

Malhar Chauhan, Prof.Abhishek Chobey 

 

Abstract— OFDM (Orthogonal Frequency Division 

Multiplexing) is spectrally efficient modulation technique used 

for higher data rate transmission. Basically OFDM system is 

very effective technique in its way ,but main disadvantage is 

Peak to Average Power Ratio. This Ratio Must be reduce to 

perfom efficient communication. Different technique can be 

used to reduce it. Here in this paper proposed technique is Tone 

reservation. 

Index Terms— Orthogonal Frequency Division Multiplexing 

(OFDM), Peak to Average Power Ratio, Problems & 

Solutions,Tone Reservation. 

I. INTRODUCTION 

OFDM (Orthogonal Frequency Division Multiplexing) is 

multi path multiplexing technique.In OFDM system Large 

number of Orthogonal ,Overlapping,narrow band sub carriers 

transmitted in parallel. In this technique higher data rate is 

divided into lower data rate. In OFDM System all sub carriers 

is arranged Orthogonally. Here as per the advantage OFDM 

system provides best performance but by seeing its 

disadvantage related PAPR efficiency can be decrease. Now, 

to reduce PAPR different techniques have proposed. In this 

paper Tone Reservation technique is proposed. We will 

discuss about this technique and its simulation in this paper. 

. 

Fig-1 OFDM Spectrum 

Periodic So, for continous time 

∫cos (2πnf 0 t) cos(2πmf 0 t)dt = 0 

II. OFDM 

Basic Principal of OFDM system is to divide high data rate 

transmission into lower data rate and that are transmitted 

simultaneously over number of subcarriers. Each of these 

signal are individually modulated and transmitted over the 

channel. And at the Receiver and signal will be demodulated 

and recombine to recover the Original Signal.Now as per the 

main aim of this paper PAPR reduction is must necessary to 

perform efficient transmission. In this paper Tone 

reservations 

with clipping technique have proposed. Here in OFDM 

system each signal is orthogonal to each other. As shown in 

figure given below Each subcarrier arranged Orthogonally in 

spectrum. Periodic signal are orthogonal when integral of 

their product is zero. 

Fig-1 Block Diagram Of OFDM System 

Basically in OFDM system QAM Modulation is used.this 

modulation technique is used to transmit the signal over 

communication channel to minimize the effect of the 

noise.this can be done in order to ensure that original data can 

be retrieve by demodulation.High data rate can be divided 

into small packets which are orthogonal to eachother.this can 

be done through QPSK modulation technique.After 

performing IFFT signal will pass from the parallel to serial 

converter.Now Focusing on PAPR (Peak to Average Power 

Ratio). 

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III. PAPR (PEAK TO AVERAGE POWER RATIO) 

Now here is the explanation of PAPR in Mathematical 

equation form. PAPR is defined as the maximum power 

occurring in the OFDM transmission to the average power of 

the OFDM transmission. Mathematical representation has 

been given below. 

PAPR = P peak = max [|x n | 2 ] 

P average E [|x n | 2 ] 

Where, P peak = Peak power of the OFDM system 

P average = average power of the OFDM system. 

E [・] is the expectation operator 

The PAPR of an oversampled version of x (t) calculated 

as per the above equation (1). Here in this equation our main 

goal is to minimize the max [|X n | 2 ]. 

Fig.3 OFDM signal containing sinusoidal high peaks 

In basics of OFDM (Orthogonal frequency division 

multiplexing) has been discussed .actually OFDM system is 

very efficient & marvelous technique in its manner, but when 

there is a merits demerits also available. So here we discuss 

one of the major drawbacks of the OFDM system. Drawback 

is high PAPR (Peak-to-Average Power ratio). PAPR means 

randomly sinusoidal leads occurred during transmission of the 

OFDM signal. So in this chapter we discuss basics of PAPR, 

why it is created & what the proposed solution are for reduce 

it. Now in Fig. 3 as per explained above high sinusoidal peak 

is shown clearly. So we can understand by seeing it what is it. 

Signal is transmitted with the sdata = 64 data symbol per 

frame to IFFT. Now here in Fig.4 original PAPR is displayed. 

And power value is 10dB. So this much power level is high 

for transmitting OFDM signal. So it contain more power. 

Here power level of PAPR is must PAPR>PAPR0 

Fig.4 Original PAPR 

In this paper main Aim is to reduce the PAPR from 10db level 

to less level so by that performance can be improved. So as 

per the introduction of PAPR we can judge that to reduce the 

PAPR is most important point in the OFDM system. Because 

of when we are talking about the high speed data 

communication in real life like video calling, high speed 

internet access, and also main point is that high speed data 

access up to 2mbps while moving on the vehicle at 100km/h, , 

Microwave terrestrial television, Digital audio broadcasting 

(DAB), 4G system, hyper LAN. So this most type of 

communication systems required high data rate. But problem 

occurs like PAPR in OFDM system prevent these types of 

facilities in the real life. So to reduce it is most important. 

This is the simulation of OFDM system to observe PAPR in it. 

So this is the basic explanation about PAPR and why it is 

reduce in OFDM system. Now there are different techniques 

has been proposed for the reducing PAPR in OFDM system. 

Tone Reservation 

IV. PROPOSED TECHNIQUE 

This technique includes no of set of reservation of tones. By 

using this technique reserved tones can be used to minimize 

the PAPR.this method is used for multicarrier transmission 

and also shows the reserving tones to reduce the PAPR.this 

technique is depend on amount of complexity.when there is 

number of tones is small rduction in PAPR may represent non 

negligible samples of available bandwidth.advantage of this 

tone reservation is very positive that no process is needed at 

receiver end. And also do not need to transmit the side 

information along with the transmitted signal. In this 

technique no of loop is used .and the signal will pass from 

each loop. And depending no of iterate the output PAPR 

value will be displayed. 

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ISSN 2249-6343 



Now as per shown the fig.6 this is the simulation result by 

using the tone reservation technique to reduce the PAPR. This 

proposed technique includes signal power & mean power . 

Now in this technique OFDM signal is transmitted after 

perform IFFT . 

X=IFFT(X*TR)*√ N 

Here as per the signal power and combination of mean power 

and CR. Reduction in PAPR has been possible. 

Fig.5 shows PAPR reduction up to 1.5 dB 

As per the technique above fig shows the previous simulation 

by keeping CR= 1, that why reduction in the PAPR can be 

done up to 1.5dB only but the times always wants some 

changes so by this technique due to some changes better 

result can be display. In table the data shows reduction in 

CCDF of PAPR. 

Table-1 Data of Reduction in CCDF for M=32 

CCDF_X = 

Columns 1 through 16 

1.0000 1.0000 1.0000 0.9980 0.9940 

0.9740 0.9230 0.8440 0.7430 0.6270 0.5080 

0.3800 0.2710 0.1870 0.1280 0.0820 


0.0560 0.0350 0.0190 0.0110 0.0070 

0.0030 0.0010 0 0 0 0 0 0 

0 0 

The signal generated in BPSK modulation.signal then signal 

passed from 1000 loops.OFDM signal’s peaks can be remove 

at some level by using this technique. In this technique by 

using previous reservation terms further can be evaluate. 

Table-2 Data of Reduction in CCDF for M=32 

CCDF_X = 


1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 

1.0000 1.0000 1.0000 0.9990 0.9970 0.9890 

0.9720 0.9330 0.8820 0.8280 


0.7470 0.6640 0.5800 0.4880 0.3970 0.3190 

0.2460 0.1760 0.1260 0.0940 0.0580 0.0410 

0.0330 0.0170 0.0110 

Fig.6 shows PAPR reduction up to 2 dB 

Clipping Ratio (CR) = 2 

Here particular in this technique loop is 1000. And the 

reduceing of data we can see here it is continuous decreasing. 

The value of CCDF is checked for 32 Times because here 

M=32. 

V. CONCLUSION 

As per the data of paper and the simulation result the 

simulated graph shows that the technique that proposed 

named tone reservation has affected at some level that we 

can show easily in the fig.6 graph. Basically this type of 

simulation will be helpful for the future of OFDM system. 

Actually day by day due to improvement of technology in 

the field of communication this type of improvement will 

widely hepful. 

REFERENCES 

[1] V. Vijayarangan, Dr. (Mrs) R. Sukanesh , “An Overview Of 

Techniques For Reducing Peak to Average Power Ratio And Its 

Selection Criteria For Orthogonal Frequency 

Divisionmultiplexing Radio Systems” Journal Of Theoretical 

And Applied Information Technology,Year 2009 ,Vol-5, No-5, 

E- Issn- 1817-3195/Issn-1992-8645 

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[2] Umar Izaz Butt, “A Study On Tone Reservation Technique For 

Papr Reduction In Ofdm” Year 2010 Dissertation .Com Boca 

Raton, Florida ISBN-10:1-59942-360-X, ISBN-13: 

978-1-59942-360-9 

[3] Malhar chauhan,Saurabh patel,Hardik patel “ Different 

Techniques to Reduce the PAPR in OFDM System” year 2012, 

International Journal of Engineering Research andApplications 

(IJERA) ISSN: 2248-9622, Vol. 2, Issue 3 

Thesis: 

[1] Mohammad Zavid Parvez Md. Abdullah Al Baki “Peak To 

Average Power Ratio (Papr) Reduction In Ofdm Based Radio 

Systems”, Master Of Science Thesis Blekinge Institute Of 

Technology May 2010. 

[2] Abhishek Arun Dash “Ofdm Systems and Papr Reduction 

Techniques in Ofdm Systems”, Bachelor Thesis, Department Of 

Electronics and Communication Enginnering National Institute 

of Technology, Rourkela 2006 – 2010. 

[3] A.H.M Shahparan “Numarical Performance Evalution Of Papr 

Reduction In Mimo Ofdm Wireless Communication” Thesis Of 

Bachelor Of Science Department Computer Science & 

Telecommunication Engineering, Noakhali Science 

Technological University,Sonapur.Nov-2011 

AUTHOR‟S PROFILE:- 

Malhar Chauhan1 Final Mtech Student 

Dept of E.C.E, RKDF Institute Of Technology ,Bhopal,India. 

Prof.Abhishek Chobey2 Professor 

Dept of E.C.E, RKDF Institute Of Technology ,Bhopal,India. 

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PAPR Reduction in OFDM system Using Tone Reservation Technique

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