OFDM modulator

[Ranjeet Kumar]

Hi,
If possible explain the different parameters of OFDM modulator like position array,no. of subcarriers, no. of prefix points and no. of fft
and how could we use these parameters to maximise Q-factor in OFDM PON.
I am uploading an osd file of 4 user OFDM , here i have problem that all 4 downlink have different Q-factor, if possible please correct it because only 2nd one having good Q-factor left are useless. Please try to explain it.

[ZULKARNAIN]

hi ranjeet..
In my opinion the OFDM block position array arranges the position of the central frequency of the OFDM spectra, but please check whether this is true.
For your reference i am attaching few links in which this is discussed which might help you.

wdm-ofdm pon

ofdm ftth network

Optisystem OFDM Block

OFDM

[Ranjeet Kumar]

Hi ZULKARNAIN,
Thank you for your efforts to make me understand.But the above discription is not quite sufficient for understanding.
My question regarding OFDM modulator parameters to optimoze the results. here i am uploading OFDM PON with 4 users in 2nd case we get very good Q-factor having position array of 1888 but others users are not havibg good Q-factor.

[FAYIQA NAQSHBANDI]

hi ranjeet,
In the recent past, the component functioned in the following fashion. Setting the Number of FFT points sets the total number of available (not necessarily used) sub-carrier positions centered at DC or 0 Hz. The number of sub-carriers would then set the total number of sub-carriers actually used (for example 4 sub-carriers might be used for a QPSK format). The position array then sets the starting point of the range of the sub-carriers used. You can refer to the link provided by alistu for further refrence.
Thanks and regards

[alistu]

Hi Ranjeet,

In order to understand the aforementioned parameters in OFDM components, please refer to the answer provided in the link I have addressed below, where I have asked the more or less the same question a while ago and here is Damian’s answer:

Optisystem OFDM Block

Please feel free to ask any further questions you may encounter. I suggest you also go through the help section of the component if you find the answer inadequate in any way (which I believe is quite comprehensive).

If you are using OS12 OFDM components, I suggest you choose the used subcarriers in between the available subcarriers, the way set in the examples provided.

Regards

[Ranjeet Kumar]

Thank you Alistu sir
I will use the parameters as per your suggestions and then will seek for improved results.

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