PAPR Reduction in OFDM by using Companding Technique

Rajasekhar Karumuri


Orthogonal frequency division multiplexing (OFDM) is a method performed in Long Term Evolution (LTE) systems to accommodate various users within a specified  bandwidth .one of the advantage of the OFDM is that, it divides a channel into several  narrow orthogonal bands and also makes them non interfering with each other. Drawback of the OFDM is PAPR.  OFDM signals passes through high power amplifiers there will be some losses that occur which leads to decrease in the efficiency of the system.  To overcome the problem of PAPR we have various methods, partial transmit sequence is one such method for reduction of PAPR. Cyclic Shifted Sequence (CSS) is a method which is an extension to the PTS method. in the CSS, shift value selection plays a major role in the proposed method along with the CSS scheme with shift value(SV) selection we add another block called as Companding as a result we get better results. 


Orthogonal Frequency Division Multiplexing (OFDM) System; Partial Transmit Sequence (PTS) Method; peak to average power ratio(PAPR)Problem; companding

Full Text:



Kee-Hoon Kim, “On the shift value set of cyclic shifted sequences for PAPR reduction in OFDM systems,†IEEE Transactions on Broadcasting, vol. 62, pp.496-500, March 2016.

B.S.Krongold and D.L.Jones, “PAR reduction in OFDM via active constellation extension,†IEEE Transactions on broadcasting, vol. 49, pp.258-268, Sep. 2003.

S. H. Müller, R. W. Bäuml, R. F. H. Fischer, and J. B. Huber, “OFDM with reduced peak-to-average power ratio by multiple signal representation,†Ann. Telecommun., vol. 52, pp. 58–67, Feb. 1997.

J.-Y. Woo, H. S. Joo, K.-H. Kim, J.-S. No, and D.-J. Shin, “PAPR analysis of class-III SLM scheme based on variance of correlation of alternative OFDM signal sequences,†IEEE Commun. Lett., vol. 19, pp. 989–992, Jun. 2015.

G. R. Hill, M. Faulkner, and J. Singh, “Reducing the peak-to-average power ratio in OFDM by cyclically shifting partial transmit sequences,†Electron. Let., vol. 36, pp. 560–561, Mar. 2000.

G. R. Hill, M. Faulkner, and J. Singh “Cyclic shifting and time inversion of partial transmit sequences to reduce the peak-to-average power ratio in OFDM,†in Proc. IEEE PIMRC, London, U.K., Sep. 2000, pp. 1256–1259.

Meixia Hu, Yongzhao Li, Member, IEEE, Wei Wang, and Hailin Zhang, Member, “A Piecewise Linear Companding Transform for PAPR Reduction of OFDM Signals With Companding Distortion Mitigation†IEEE Trans Broadcast, vol.60, Sep. 2014.