5. How OFDM works
It distributes the data over a large number
of carriers that are spaced apart at precise
frequencies. This spacing provides the
"orthogonality" in this technique which
prevents the demodulators from seeing
frequencies other than their own.
7. C-OFDM
Coded OFDM
Digital Audio
Broadcasting (DAB)
Digital Video
Broadcasting (DVB-T)
COFDM offers real
benefit in the
presence of isolated
narrow-band
interfering signals
8. Multiple Input, Multiple Output
OFDM (MIMO-OFDM)
Developed by Iospan Wireless
Uses multiple antennas to transmit
and receive radio signals
Spatial multiplexing
9. V-OFDM
Vector OFDM
Developed by CISCO
Increases subscriber coverage
Lowers the cost of provisioning and
deploying infrastructure
Employs both frequency and spatial
diversity
Creates a robust processing technique for
multi-path fading and narrow band
interference
11. W-OFDM
Wideband OFDM
Invented by Wi-LAN
Large spacing between carriers
Advantages:
- Optimal performance against Multi-path
- Less sensitive to carrier offset
-Optimal power efficiency of the transmitter
amplifier
- More immune against fading
12. Flash-OFDM
Fast-hopped OFDM
Wide-band spread-spectrum
technology
Avoids the compromises inherent in
other mobile data systems
Capability to work around interfering
signals
13. Differences from other multiplexing
techniques
OFDM versus WDM
-more flexible
-higher bandwidth efficiency
14. Differences from other multiplexing
techniques
OFDM versus TDM
-number of carriers
-synchronization
-sensitivity
-capacity/efficiency advantages
-complexity and cost issues
15. Applications
Digital Audio and Video
Broadcasting
Asymmetric Digital Subscriber
Line (ADSL)
Wireless Networking
Power-line Technology
