national institute of science & technology ofdm deepak ranjan panda (ei200118175) [1] orthogonal...
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![Page 1: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/1.jpg)
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yOFDM
Deepak Ranjan Panda (EI200118175)
Orthogonal Frequency Division multiplexing (OFDM)
Technical Seminar PresentationBy
Deepak Ranjan Panda Roll # EI200118175
Under the guidance of
Mr. Nalla Srinivasu
![Page 2: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/2.jpg)
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yOFDM
Deepak Ranjan Panda (EI200118175)
What is OFDM?
• OFDM is a multicarrier system
• uses discrete Fourier Transform/ Fast Fourier Transform(DFT/ FFT)
• Available bandwidth is divided into very many narrow bands
![Page 3: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/3.jpg)
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Deepak Ranjan Panda (EI200118175)
How to implement OFDM ?
Fast fourier transform is primarily used
At transmitter end coding is done for error correction
Modulated by QAM
At receiver end the data is recovered by IFFT
![Page 4: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/4.jpg)
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Deepak Ranjan Panda (EI200118175)
Why use OFDM
![Page 5: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/5.jpg)
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Deepak Ranjan Panda (EI200118175)
WIDEBAND OFDM
Variation of OFDM
Spacing between the carriers is large enough
A way by which broadband communication can be established.
Errors in the timing of the digitization can be removed by division of channel’s frequency response
![Page 6: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/6.jpg)
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Deepak Ranjan Panda (EI200118175)
TASKS FOR THE RECEIVER STRUCTURE
Timing synchronization
Frequency synchronization
Sampling-clock synchronization
![Page 7: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/7.jpg)
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Deepak Ranjan Panda (EI200118175)
Coded orthogonal frequency division multiplexing
•A modulation scheme used by Digital Audio Broadcast
•Multipath
![Page 8: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/8.jpg)
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Deepak Ranjan Panda (EI200118175)
Wideband & narrowband wireless transmission
The natuer of wireless communication depends on duration of transmission of symbols
The duration from first received path to last received path gives maximum delay
![Page 9: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/9.jpg)
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Deepak Ranjan Panda (EI200118175)
Error correction coding
•COFDM uses convolution coding
•For every one bit input the output is more than one bits
•No.of output bits depend on code rate being used
![Page 10: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/10.jpg)
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Deepak Ranjan Panda (EI200118175)
COFDM Transmitter
![Page 11: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/11.jpg)
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Deepak Ranjan Panda (EI200118175)
OFDM MODULATOR
![Page 12: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/12.jpg)
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Deepak Ranjan Panda (EI200118175)
FREQUENCY SPECTRA OF SUB-CARRIERS
![Page 13: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/13.jpg)
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Deepak Ranjan Panda (EI200118175)
COFDM Receiver
![Page 14: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/14.jpg)
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Deepak Ranjan Panda (EI200118175)
Cyclic Prefix
• Including a cyclic prefix to the OFDM symbol
![Page 15: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/15.jpg)
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Deepak Ranjan Panda (EI200118175)
Applications of OFDM
The MMDS system
Mobile reception
Mobile transmission
![Page 16: National Institute Of Science & Technology OFDM Deepak Ranjan Panda (EI200118175) [1] Orthogonal Frequency Division multiplexing (OFDM) Technical Seminar](https://reader036.vdocument.in/reader036/viewer/2022082711/56649eba5503460f94bc240f/html5/thumbnails/16.jpg)
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Deepak Ranjan Panda (EI200118175)
CONCLUSION
During the development of OFDM system it became obvious that this has great potential than just transmission to a fixed installation