PAPR REDUCTION IN OFDM SYSTEM USING HADAMARD AND COMPANDING TRANSFORM

Presented by : AUGUSTINE.F1571010003,

II year, M.Tech- Communication Systems

Project guide : Dr. R.KUMARProfessor/ Dept. of ECE

OUTLINE

• Overview• Literature review• Drawbacks/Limitations of existing work• Objective of research work• Challenges involved in the research work• Mode of the implementation• Expected outcomes• Schedule for Phase I• References.

OVERVIEW-OFDM

• Orthogonal multicarrier modulation is an efficient scheme for high data rate signals.

• excellent robustness in multi-path & frequency selective fading. Cyclic prefix preserves orthogonality between

sub-carriers• Reduces the computational complexity in equalizers.• Low computational complexity implementation

(FFT/IFFT).

LITERATURE REVIEW

• PAPR is one of the major issues for OFDM systems.• Summation of Orthogonal carriers can result in large peak

values and low average values ,This variation is referred to as Peak-to-Average Ratio.

• Linear Amplifiers and high dynamic range in the transmitter hardware

Expensive Inefficient - Consumes more power

• If non-linear amplifiers are used Spectral spread (Out of band radiation) In-band distortion

EXISTING SCENARIO

LIMITATIONS OF EXISTING WORK

Complexity.. Complexity..Complexity..!

• Multiple signal representation increases the transmitter complexity significantly.

• Tone reservation, tone injection, and ACE require moderate/high computations.

• Out-of-band distortion.• In-band distortion.

ANY LOW COMPLEXITY SCHEMES?• A joint companding and hadamard transform is

proposed.

OBJECTIVES OF RESEARCH WORK

• Alternate approach for the existing technique is the joint companding and hadamard transform.

• The principle goal of this technique is to reduce the maximum instantaneous power.

• Companding transform performs compression and expansion to reduce the distortion of the signal.

• Hadamard transform is to reduce the autocorrelation of the input sequence .

CHALLENGES INVOLVED IN THE RESEARCH WORK

• To solve the peak-to-average power ratio by minimizing the instantaneous power.

• Low bit error rate.

MODE OF IMPLEMENTATION

MATLAB R2010A

EXPECTED OUTCOMES

• Low bit error rate performance.

• PAPR calculation(CDF).

• SNR calculation.

SCHEDULE FOR PHASE I

• August Review : OFDM transmitter design with QPSK/QAM modulation,

PAPR calculation.• September Review : multipath channel design and

OFDM receiver design.• October Review : BER calculation, Hadamard and

companding transform--theoretical

calculation

REFERENCES

• [1] T. Jiang and Y. Imai, “An overview: peak-to-average power ratio reduction techniques for OFDM signals,” IEEE Trans. On WirelessCommunications, June 2008.

• [2] S.H. Han, J. H. Lee, “An overview of peak-to-average power ratio reduction techniques for Multicarrier transmission,” IEEE Transaction on Wireless Communication, April 2005.

• [3]Xiao Huang, J H Lu, Jun Li Zhen, etal “Companding Transform for Reduction in Peak-to-Average Power of OFDM signals”, IEEE transactions on wireless communications, Nov,2004.

REFERENCES

• [4] Xiao bin Wang, “Reduction of peak-to-average power ratio of OFDM system using A companding technique,” IEEE Transaction on Broadcasting, Sep 1999.

• [5] Park, M., Heeyong, J., Cho, N., Hong, D, and Kang, C., “PAPR reduction in OFDM transmission using Hadamard transform”, IEEE International Conference on Communications, June2000.

• [6] Xiaodong zhu, Guangxi Zhu, Tao Jiang, “Reducing the peak-to-average power ratio using unitary matrix transformation. IET Communications,2009.