Ofdm for optical communications co ofdm
-
Upload
jaya-m -
Category
Technology
-
view
247 -
download
6
Transcript of Ofdm for optical communications co ofdm
ADVANTAGES
effective solution to inter symbol
interference.
Less complexity.
Digital transmitter and receivers
2
OFDM TECHNOLOGY
Multicarrier modulation technique.
Different from fdm / wdm.
3
OFDM TECHNOLOGY….
4
OFDM SYSTEMDESCRIPTION
IFFT
OFDM baseband signal can be
implemented by IDFT
5
FFT
• At receiver
FFT
6
Cyclic Prefix for OFDM
For an OFDM symbol
7
NEED OF CP???
CP eliminates ISI,ICI,
Let the received signal at time t be
CP will eliminate ISI if
receiver FFT window is aligned with the start of
the main symbol period of the first arriving
signal.
delay spread does not exceed the CP
8
NEED OF CP???
9
OFDM SYSTEMDESCRIPTION…
10
OFDM for Optical Communications
classified into two main categories:
Coherent detection (DD-OOFDM)
Direct detection (CO-OFDM)
Each are different according to their underlying
techniques
future of optical communication is the coherent detection .
11
CO-OFDM
12
basic functional blocks
RF OFDM signal transmitter,
RF to optical(RTO) up-converter,
Fiber links,
the optical to RF (OTR) down-converter,
RF OFDM receiver
13
DISADVANTAGES OF OFDM
High Peak-to-Average Power Ratio.
Sensitivity to Frequency Offset, Phase
Noise
Difficulty and Cost of OFDM
Implementation
14
CONCLUSION
Typical OFDM transmitter and receiver
described and the roles of main signal
processing blocks explained.
Advantages and disadvantages of ofdm
were discussed.
15
Any queries ???....
16
THANK YOU!!!
17