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Help required on Dispersion Compensation by DSP

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(joined August 2015)
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Hi,

I am working on millimeter wave radio over fiber converged network and now I want to compensate dispersion with DSP. The problem is the dispersion because from back to back the setup works fine but when I include fiber the constellation is not good. I am using 16 QAM OFDM modulated on 60 GHz mmWave carriers. Can you help me regarding this and which steps are required to form a DSP code to compensate CD. Now I am using digital filters method to compensate it but it’s not working. Also my setup is a direct detection system. Thanks

Best regards,

Umar Farooq

Responses (3):

  • #53339
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    UMAR FAROOQ
    Participant

    Hi,

    I am working on millimeter wave radio over fiber converged network and now I want to compensate dispersion with DSP. The problem is the dispersion because from back to back the setup works fine but when I include fiber the constellation is not good. I am using 16 QAM OFDM modulated on 60 GHz mmWave carriers. Can you help me regarding this and which steps are required to form a DSP code to compensate CD. Now I am using digital filters method to compensate it but it’s not working. Also my setup is a direct detection system. Thanks

    Best regards,

    Umar Farooq

  • #53550
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    Ahmad Atieh
    Participant

    Dear Umar,
    thanks for your enquiry.
    I am not sure what the cause of bad constellation after you include the fiber. I need to know the length of the fiber, bit rate, number of OFDM tones, etc. to provide feedback.
    Could you please send me your project as a zip file to ahmad.atieh@optiwave.com and I’ll try to provide some feedback and recommendations?
    Regards,
    Ahmad

  • #53613
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    UMAR FAROOQ
    Participant

    Hi,

    Thanks for your reply.
    Here are the main Parameters.
    Length of fiber= 25 Km
    Bit Rate= 5 G Bits/s
    No of OFDM Carriers =16
    Each carrier has 16 QAM Modulation
    This setup is converged with 60 GHz millimeter wave carriers and then after fiber these carriers are detected on OFDM receiver. Its a direct detection system.
    The setup works fine for btb and upto 5 Km but when I increase the fiber I got the very bad constellation.
    Now I want to compensate this dispersion with DSP code file.

    Best regards,
    Umar Fraooq

  • #53614
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    Ahmad Atieh
    Participant

    Hello,
    unfortunately, I can’t help you without the project layout. I’ve asked you to email me your project to ahmad.atieh@optiwave.com as a zip file. I need to check the whole system to be able to provide feedback.
    Please communicate with me on my email to discuss further.
    Regards,
    Ahmad

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