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Pilot carrier and it's position?

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(joined August 2015)
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I am trying to realize coherent OFDM using 16-QAM modulation Scheme using OptiSystem simulation platform. But, I am confused about what number of the pilot carrier should I use for better result considering 512/1024 subcarrier OFDM. 

I found from literature that “Pilots are used to track the residual phase error if present after frequency correction. Without this correction, the constellation points start rotating either +ve/-ve angle. It is very much sensitive at higher constellation.” at http://www.edaboard.com/thread219563.html 

Please help

Pilot carrier and its position?. Available from: https://www.researchgate.net/post/Pilot_carrier_and_its_position [accessed Apr 8, 2017].

With regards,
Dhiman Kakati

Responses (2):

  • #42953
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    Dhiman Kakati
    Participant

    I am trying to realize coherent OFDM using 16-QAM modulation Scheme using OptiSystem simulation platform. But, I am confused about what number of the pilot carrier should I use for better result considering 512/1024 subcarrier OFDM. 

    I found from literature that “Pilots are used to track the residual phase error if present after frequency correction. Without this correction, the constellation points start rotating either +ve/-ve angle. It is very much sensitive at higher constellation.” at http://www.edaboard.com/thread219563.html 

    Please help

    Pilot carrier and its position?. Available from: https://www.researchgate.net/post/Pilot_carrier_and_its_position [accessed Apr 8, 2017].

    With regards,
    Dhiman Kakati

  • #43152
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    Dhiman Kakati
    Participant

    Till waiting for reply

  • #43303
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    Dhiman Kakati
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    I got a suggestion from Mark, Optiwave support as follows: Find it worthy to share here

    It’s basically a trial and error process (there is no set way to allocate the pilot tones). I suggest trying a small number of pilot tones and then increasing to see if the performance improves.

    In terms of where you can place the pilot tones, these can only be on any of the allocated sub-carrier locations. So if you have sub-carriers from FFT points 25-104, the pilot symbols can be placed on any of the FFT points from 25 to 104 (for example 30, 50, 60, 80, 100)

    I hope this helps

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