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A Proposed Constant Amplitude Modulator in OFDM Systems

W .Saad, N. El-Fishawy, S. El-Rabaie, M. Shokair


The Orthogonal Frequency Division Multiplexing(OFDM) technique has recently recieved considerable attention for wireless networks.Despite its advantages,it has a major drawback of its high Peak-To-Average Power Ratio(PAPR)value which affects the system efficiency and the cost.In this paper, a proposed system is discussed to achieve 0 db PAPR depends on a proposed block,called Constant Amplitude(CA)modulation.It consists of three sub-blocks(inserting zero,inserting samples,and comparing samples).The whole mathematical analysis is presented for the proposal system.Additionaly the complexity evolution is explained.Only four simple adders,two simple subtractors,and two simple comparators are needed for the proposed CA modulator.Therefore,it is simple and applicable block.Afterwards,many MATLAB simulation programs are executed.Time and frequency domain behaviors are presented.Furthermore, in-band distortion introduced by the Proposed CA modulation is calculated in terms of Error Vector Magnitude(EVM).Moreover,the proposed system outperforms  the conventional one when compared in terms of PAPR,equalization,and BER under Additive White Gaussion Noise(AWGN)channel and multipath fading channels.In addition,the impact of the proposed scheme design parameter(the number of inserted samples) is studied.The more inserted samples are added,the more accurates results  are obtained,the less EVM values are achieved,the less transmission throughput values are occured.


OFDM,Multipath Fading Channels,PAPR,BER,Equalizer and EVM.

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S.Hara and R.Prasad,Multicarrier Techniques for 4G Mobile Communications. Artech House, 2003.

J.G.Andrews, A.Ghosh, and R.Muhamed,Fundamentals of WiMAX:Understanding Broadband Wireless Networking. T.S.Rappaport. Ed.Pearson Education,Inc., 2007.

H.Y. Sakran,M.Shokair and A. A. Elazm, "Combined interleaving and companding for paprreduction in ofdm systems,"Progress In Electromagnetics Research C,vol. 6,pp. 67-78,2009.

A.Sayed-Ahmed,M.Shokair, and E.S. El-Rabiae, "Papr reduction for Ifdma using a reduced complexity pts scheme,"in 29th NRSC, Cairo University,Egypt.,2012.

W.Saad, N.El-Fishawy,S.EI-Rabiae,and M.Shokair,"An efficient technique for ofdm system using discrete wavelet transform,"In Proceddings of GPC.pp.533-541.2010.

K.R.Rao and P.Yip.The transform and data compression Handbook,A.Poularikas and R.C.Drof,Eds The Electrical Engineering & Applied Signal Processing Series,2001. Beek,P.Odling, S.Wilson, and P.Borjesson,"Orthogonal-division multiplexing (ofdm),"In review of radio science 1996-99,Intern.Union Of Radio Science(URSI),1999.

I.Koffman and V.Roman, "Broadband wireless access solutions based on ofdm access in ieee 802.16," IEEE Commun.Mag., vol.40,no.4,pp. 96-103, 2002.

Y.LIANG, "Block-iterative gfde (bi-gfde) for cpcdma and mc-cdma,"Proc.IEEE VTC, vol.5, pp. 3033-3037, 2005.

S.D. Falconer, A.Ariyavisitakul, A. Benyamin-Seeyar, and B.Eidson,"Frequency domain equalization for single-carrier broadband wireless systems,"IEEE Commun. Mag., vol.40, pp. 58-66,2002.

R.Prasad,OFDM for wirelesscommunications systems. Artech House,Inc., 2004.

H.G.Ryu, B.I.Jin, and I.B.Kim, "Papr reduction using soft clipping and aci rejection in ofdm system,"IEEE Transactions, vol, 48, pp. 17-22 2002.

S. SLIMANE, "Reducing the peak to average power ratio of ofdm signals through precoding," IEEE Trans. Veh. Technology, vol.56, pp.686-695, 2007.

C. Guoguang, R.Ansari and Y. Yingwei, "Improved peak windowing for papr reduction in ofdm," in Vehicular Technology Conference(VTC),26-29 April 2009.

K.Park and I.Park, "Low-complexity tone reservation for papr reduction in ofdm communication systems,"Very Large Scale Integration(VLSI)Systems, IEEE Transactions on, vol. PP, Issue:99, pp. 1-5,2011.

J.Hou, J. Ge, and J. Li, "Peak to average power ratio reduction of ofdm signals using pts scheme with low computational complexity,"IEEE Trans. on broadcasting,vol 57, pp. 143-148, 2011.

S.Mohammady, R. M. Sidek, P. Varahram, M. N.Hamidon, and N.Sulaiman, "study of papr reduction methods in ofdm systems," in Advanced Communication Technology(ICACT)Conference,13-16 Feb 2011.

H.-G Ryu J.E. Lee. and J.S.Park. "Dummy sequence insertion (dsi) for papr reduction inthe ofdm communication system,"Consumer Electronics, IEEE Transactions, vol.5, pp,89-94, 2004.

S.P.Maity. S.Maity, and J.Sil, "Multicarrier spread spectrum watermarking for secure error concealment in fading channel," Springer Telecommunuication Systems Journal (TSMJ),Online on June 30,2010.

M. Shokair and H. Sakran , "Performance of sdm/cofdm system in the presence of non linear power amplifier ," Springer Telecommunication System Journal(TSMJ), Online on 29 January,2011.

S.Ahmed and M.Kawai, "Interleaving effects on ber fairness and papr in ofdma system,"Springer Telecommunication Systems Journal(TSMJ),Online on July 30,2011.

Part 16:Air Interface for Fixed and Mobile Broadband Wireless Access Systems ,IEEE Standard for local and

Metropolitan Area Networks Std.

3rd Generation Partnership Project, 3GPP TS 25.101 - User Equipment (UE) Radio Transmission and Reception(FDD)(Release 7), Sep. 2007,Section B.2.2., Std.

C. Zhao and R. J. Baxley, "Error vector magnitude analysis for ofdm systems,"in Signals,Systems and computers,2006.ACSSC'06.Fortieth Asilomar Conference on, Oct.29-Nov. 1 2006.

M.D.McKinley,K.A.Remley,M.Myslinski,J.S.Kenney,D.Schreurs,and B.Nauwelaers, "Evm Calculation for broadband modulated signals,"in 64th ARFTG Conf. Dig., Orlando, Dec.2004.


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