Home Forums SYSTEM Data allocation to OFDM subcarriers ignoring DC and pilots

Data allocation to OFDM subcarriers ignoring DC and pilots

Profile Photo
(joined August 2015)
Participant

Hi everybody,
I want to insert pilot data at certain subcarriers. If I do so, how can I make the input data to skip those subcarriers carrying pilots in optisystem or this is done by default?

And please let me know how to change the bandwidth of the OFDM symbol which I asked earlier but didn’t get any reply on this. THe system design for OFDM is available in the link given below.

OptiSystem – Hot Topics

Thank you.

Responses (5):

    • #27588
      Profile Photo
      Gokul Boro .
      Participant

      Hi everybody,
      I want to insert pilot data at certain subcarriers. If I do so, how can I make the input data to skip those subcarriers carrying pilots in optisystem or this is done by default?

      And please let me know how to change the bandwidth of the OFDM symbol which I asked earlier but didn’t get any reply on this. THe system design for OFDM is available in the link given below.

      OptiSystem – Hot Topics

      Thank you.

    • #27622
      Profile Photo
      alistu
      Participant

      Hi Gokul,

      From the OptiSystem samples and previous discussions, you would just need to give the location of pilot signal and give their number in the BER Test Set, and the software is supposed to neglect them while calculating the BER (I don’t know if the training output on the OFDM modulator also transmits pilot symbols though, but if it is so, you can be sure about the data being completely separated).

      Regards

    • #28428
      Profile Photo
      Gokul Boro .
      Participant

      Hi Alistu,

      I would like to know if the software skips the DC subcarrier too.
      Also please let me know how do I set the bandwidth.

      • #28432
        Profile Photo
        alistu
        Participant

        Hi Gokul,

        I don’t think the software neglects DC subcarriers (otherwise what to do about the information) As for the bandwidth, it is set to 0.62*bit rate by default, but you can reduce it further. I have tried 0.3*bit rate and I believe no information was lost (for OFDM with 4-QAM). You can reduce it to the point where the reduction has an effect on BER.

        Regards

    • #28502
      Profile Photo
      Gokul Boro .
      Participant

      DC subcarrier is not neglected means there is no possibility of 802.11a/g being simulated in optisystem using OS component. I could have done it with OS12 OFDM modulation Measured component but in this component there is no way to use pilot data. Did you ever try to simulate 802.11a/g? If so please give me some idea how you did it in Optisystem.

      • #28511
        Profile Photo
        alistu
        Participant

        Unfortunately I haven’t. Are you sure if position array capibility in OFDM modulator components cannot be of any help to you in such a case? (Please regard Damian’s explanation on position array if you think it may be helpful)

        Optisystem OFDM Block

        Regards

Login You must be logged in to reply to this topic.