Now, I am working on OFDM equalization, according to what I understood, Adding CP into the OFDM block change the convolution from linear to circular. That circular convolution enables using point-wise equalizer or one tap equalizer such that ZF or MMSE equalizer.

ZP-OFDM is a different scheme, where the CP is replaced by zeros. As I understood, ZP-OFDM should achieve the same performance of CP but under more complex equalization.

So, What means by complex equalization?? Is it time-domain equalization ? Could someone explain for me which equalizer we can adopt with ZP-OFDM in order to achieve similar/near performance of CP-OFDM ?


Hint: you could convert zero padded ofdm into cyclic ofdm at the receiver, and use the same equalization. Though there will be more noise on this scheme.

I had asked a puzzle some time back on this topic:

Modelling zero padded OFDM as circular convolution between channel and FFT frame

  • $\begingroup$ That's really interesting !! have you checked that idea by simulation? .. Thank you very much for that comment. And I still need to know how can we equalize the channel in ZP-OFDM. $\endgroup$ – Fatima_Ali Jul 13 '20 at 9:39
  • $\begingroup$ There are techniques you can Google them or find in literature, ZP OFDM is used in marine communications, mostly non linear equalization is required $\endgroup$ – Dsp guy sam Jul 13 '20 at 9:41
  • $\begingroup$ Additionally, I think that is feasible in case if the length of channel $L$ is known. $\endgroup$ – Fatima_Ali Jul 13 '20 at 9:45
  • $\begingroup$ Regarding the techniques, I tried googling them, I couldn't find clear way. $\endgroup$ – Fatima_Ali Jul 13 '20 at 9:45
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    $\begingroup$ Even to decide the CP in CPOFDM you would need to know the delay spread /channel taps to decide on the length of CP $\endgroup$ – Dsp guy sam Jul 13 '20 at 9:57

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