This document discusses reducing peak-to-average power ratio (PAPR) in MIMO-OFDM systems using linear companding transforms. It proposes applying companding transforms like linear companding transform (LCT) and linear nonsymmetrical companding transform (LNST) to reduce PAPR without restricting system parameters. The method aims to achieve a very low PAPR, reduce signal degradation from nonlinear power amplifiers, and have high spectral efficiency and signal-to-noise ratio while staying within bandwidth and complexity limits. The performance is analyzed through MATLAB simulations.

1. Under The Guidens Of Mr.K.N.Vijeyakumar,M.E, PhD Presented by R. Selvakumar.B.Tech MIMO-OFDM Link performance with Reduction of PAPR Using Linear Companding Transform 03.10.2009 MIMO-OFDM&PAPR

2. Area of work: OFDM (Orthogonal Frequency Division Multiplexing)

3. TYPES OF OFDM MIMO-OFDM C-OFDM V-OFDM W-OFDM Flash-OFDM MIMO-OFDM : I s a modulation technique for transmitting large amounts of digital data over a radio wave. MIMO U ses multiple antennas to transmit and receive radio signals 03.10.2009 MIMO-OFDM&PAPR

4. Objective: To use linear companding transform for ofdm signals, To make performance analysis in terms of peak to average power reduction and bit error rate.

5. LITERATURE SURVEY Optimal Pilot Sequence Design for Channel Estimation in MIMO OFDM Systems. IEEE COMMUNICATIONS LETTERS, VOL. 10, NO. 1, JANUARY 2008. Linear Companding Transform for the Reduction of Peak-to-Average Power Ratio of OFDM Signals. IEEE TRANSACTIONS ON BROADCASTING, VOL. 55, NO. 1, MARCH 2009 PAR-Constrained Training Signal Designs for MIMO OFDM Channel Estimation in the Presence of Frequency Offsets . IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 8, AUGUST 2008. PAPR Reduction in OFDM Systems IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 6, JUNE 2007 MIMO-OFDM Channel Estimation in the Presence of Frequency Offsets. IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 6, JUNE 2008. 03.10.2009 MIMO-OFDM&PAPR

6. LITERATURE SURVEY OFDM joint data detection and phase noise cancellation based on minimum mean square prediction error . Signal Processing 89 (2009) 502–509 journal homepage: www.elsevier.com/locate/sigpro . Channel estimation in space and frequency domain for MIMO-OFDM systems . June 2009,science/journal/10058885. Is PAPR reduction always justified for OFDM? An Improved LS Time Domain Channel Estimation Algorithm Based on MIMO-OFDM System. 2009 International Conference on Networks Security, Wireless Communications and Trusted Computing. Adaptive Resource Allocation with Multiuser Interference Cancellation for MIMO OFDM Systems The Frequency Offset Estimator Based on All-Phase FFT for OFDM Systems. 2009 International Conference on Signal Processing Systems 03.10.2009 MIMO-OFDM&PAPR

7. EXISTING METHOD OFDMPAPR concept : Analysis different OFDM PAPR reduction techniques, based on computational complexity, bandwidth expansion. OFDMPAPR Reduction Methods: Clipping Additive Correction Function Peak Windowing BERC Technique Scrambling Coding Selective Mapping Partial Transmit Sequence (PTS) 03.10.2009 MIMO-OFDM&PAPR

8. BASE PAPERS An Overview: Peak-to-Average Power Ratio Reduction Techniques for OFDM Signals Tao Jiang, Member, IEEE, and Yiyan Wu, Fellow, IEEE IEEE TRANSACTIONS ON BROADCASTING, VOL. 54, NO. 2, JUNE 2009. problem in existing method: Non Linear Districution is more. In band noise => Increase BER , PAPR is more. PAR-Constrained Training Signal Designs for MIMO OFDM Channel Estimation in the Presence of Frequency Offsets IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 7, NO. 8, AUGUST 2008. problem in existing method: Very sensitive to frequency errors (Tx. & Rx. offset) peak to average ratio( PAPR ) is more.

9. BASE PAPER Optimal Training Design for MIMO OFDM Systems in Mobile Wireless Channels IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 51, NO. 6, JUNE 2005 problem in existing method: Intercarrier Interference (ICI) between the subcarriers (ICI) . PAPR is more. Channel estimation in space and frequency domain for MIMO-OFDM systems . June 2009, www.sciencedirect.com/science/journal/10058885 problem in existing method: More Degradation peak to average ratio ( PAPR ) is more.

10. BASE PAPER LINEAR COMPANDING TRANSFORM FOR THE REDUCTION OF PEAK-TO-AVERAGE POWER RATIO OF OFDM SIGNALS . IEEE TRANSACTIONS ON BROADCASTING, VOL. 55, NO. 1, MARCH 2009 03.10.2009 MIMO-OFDM&PAPR

11. PROPOSED METHOD Concept: A major drawback of orthogonal frequency-division multiplexing (OFDM) signals is their high peak-to-average power ratio (PAPR), which causes serious degradation in performance when a nonlinear power amplifier (PA) is used. Appling Companding transform (CT) method to reduce PAPR without restrictions on system parameters Techniques : Linear Companding Transform(LCT). Linear Nonsymmetrical Companding transform (LNST) 03.10.2009 MIMO-OFDM&PAPR

12. CHARACTERISTICS Very less Peak to average power ratio(PAPR). Reducing Serious Degradation in an OFDM. Optimal amplitude and phase of peak reduction carriers(PRC). Reliable and have a high spectral efficiency. Achieve more signal to noise ratio. Bandwidth and complexity limits. 03.10.2009 MIMO-OFDM&PAPR

13. IMPLEMENTATION Used Terms: Tool Used: Orthogonal Frequency-division Multiplexing (OFDM), Peak-to-Average Power Ratio (PAPR). Nonlinear Power Amplifier (PA), MAT-LAB Simulation Tool. 03.10.2009 MIMO-OFDM&PAPR

14. THANK YOU 03.10.2009 MIMO-OFDM&PAPR