Division multiplexing seminar report On Orthogonal frequency Division multiplexing Presentation by: Sudhir Kumar Bhukta, Regdn. No. - 0901222136 Nihar Ranjan Jena, Regdn. No. - 0901222105

Highlights Concept of OFDM with spectrum Digital modulation basics Principles OFDM process with flow chart Frequency samples Single & multi carrier system Multichannel systems Advantages & disadvantages Applications Conclusion

What is OFDM? OFDM =>Orthogonal Frequency Division Multiplexing It is a process of splitting of higher data streams into a number of lower data streams simultaneously.

OFDM DEFINITION OFDM = Orthogonal FDM Carrier centers are put on orthogonal frequencies ORTHOGONALITY - The peak of each signal coincides with trough of other signals Subcarriers are spaced by 1/Ts

Spectrum of OFDM

Digital modulation basics Types digital modulation OFDM uses combination of ASK and PSK.

PRINCIPLES Multicarrier transmission. Time-domain spreading. Frequency-domain spreading.

OFDM is a Block Process

Ofdm flowchart

frequency samples

Single Carrier System

Multi-Carrier System

Multichannel System

OFDM Advantages Efficiently Deals With Channel Delay Spread Enhanced Channel Capacity Efficiently Deals With Multi-path Fading Adaptively Modifies Modulation Density Robustness to Narrowband Interference

OFDM Disadvantages OFDM Sensitive to Small Carrier Frequency Offsets OFDM Exhibits High Peak to Average Power Ratio High Frequency Phase Noise Sampling Clock Offsets

Applications Digital Audio and Video Broadcasting Wireless Networking Power-line Technology

CONCLUSION In simulation OFDM is used over an AWGN channel. In hardware comparison OFDM has lower potential. OFDM produces low hardware complexity. It is a suitable modulation technique for high performance wireless telecommunication.

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