30 March 2018

Advantages and disadvantages of OFDM

OFDM stands for orthogonal frequency division multiplexing, it has been used in many high data rates wireless communication system because of the many advantages it provides. This article gives information about the advantages and disadvantages of OFDM  to know more details about it.

Advantages of OFDM :
  • More resistance to frequency selective fading than single carrier system because it divides to the overall channel into multiple narrowband signals that are affected individually as flat fading sub-channels
  • Interference appearing on a channel may be bandwidth limited and in this way will not affect all the sub-channels this not all the data is lost
  • Very resilient to inter-symbol and inter-frame interference
  • It is possible to recover symbols lost due to the frequency selectivity of the channel and  also a narrow-band interference using adequate channel coding and interleaving
  • Maor efficient use of the available spectrum using close-spaced overlapping sub-carriers
  • Using multiple sub-channels, the channel equalization becomes much simpler that is cause issue with a CDMA method
  • Simple implementation by the mean of FFT
  • Eliminates ISI and IFI by the use of a cyclic prefix
  • Provide good protection against co-channel interference
  • High transmission bit rates
  • A chance to cancel any channel so it affected by fading device
  • Low sensitivity to time synchronization error
  • Facilitates single frequency networks ( SFN )
  • Tuned subchannel receiver filters are not required
  • It is able to protect  total energy loss at the frequency domain
Disadvantages of OFDM :
  • Require highly linear amplifier
  • Sensitive to carrier offset and drift
  • Sensitive to frequency synchronization problems
  • Inter-carrier interference between the sub-carrier
  • Loss of efficiency caused by cyclic prefix or guard of interval 
  • High power transmitter amplifier needs linearization
  • High peak to average power ratio
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