Orthogonal Frequency Division Multiplexing (OFDM)

1
Fourier Based OFDM Communication
Author Pongsakdi Lovajana Supervisor Dr
John Homer

• Orthogonal Frequency Division Multiplexing (OFDM)
• Known as a special form of multi-carrier
  modulation.
• Particularly suited for transmission over a
  dispersive channel.
• Transmission of signal is carried out in
  parallel on different frequencies.
• Main attraction is the capability to provide
  large data rates with sufficient robustness
  to multi-path interference such as Inter
  Symbol Interference (ISI) and fading.

• Methodology Fourier Transform
• Reduces the number of modulators and filters
  at the transmitter as well as demodulators at
  the receiver.
• Effects of fading would be spread out over
  many bits.

• Simulation and Results

Transmitted SignalReceived Signal

• From the results shown above, thereare still
  errors made in the Fourier transform method that
  is used in OFDM.

• Further Development
• Fourier transform is still found tobe
  susceptible to ISI and has limitedsuitability.
  Another method that is worth looking into is
  using waveletanalysis to substitute the method
  ofusing Fourier transform in OFDM.

• Objective
• The objective of this thesis is to develop and
  simulate a Fourier based OFDM technique and find
  out the performance in terms of its
  Signal-to-Noise ratio (SNR) and Bit Error Rate
  (BER).