OFDM , QAM 64

[Mohamed Ajina]

Can you find a mistake in the attached circuit
I can not get the correct results

[Ravil]

Hi Mohamed,

Unfortunately, I can’t open your file with my version of OptiSystem. Do you have a chance to upload a screen shot?

[Mohamed Ajina]

Hi Ravil

You may use the software version 13.0.1 or 13.0.2

[Damian Marek]

Hi Mohamed,

I noticed in your file you are using the older OS 12 OFDM Mod/Demod. In the recent update 13.0.2 the components were changed and I suggest you use them if you have access to them. They are much more robust!

Regards

[Mohamed Ajina]

Hi Marek

Am I using the OFDM correct & The correctly results ?
( QAM 16 )

Regards

[Damian Marek]

The BER is 1 and generally for higher modulation and OFDM the BER Test Set is a better tool to use. Your project looks fine besides that, but I would really suggest the newer OFDM components.

[Mohamed Ajina]

Hi Marek

I am asked how can I find the relationship between BER and OSNR (What is the method) ?
note attachment

[Damian Marek]

We have a tutorial on parameter sweeps that would help you out. In addition there is a WDM Analyzer component that will calculate the OSNR value for each sweep.

[Mohamed Ajina]

Hi Mr. Marek

In the design circle OFDM – QAM , why used single mode fiber (SMF)
and why do not used Multi-mode fiber

Regar

[Dr Rk Sethi]

Hi Mohamed Ajina,
You can use Multi-mode fiber. It depends on the application.
Normally, Multimode fiber will permit short transmission distances of up to about 10 miles and will permit the use of comparatively inexpensive fiber optic communication transmitters and receivers. It will be bandwidth limitations of a few hundred MHz per Km of length. On the other hand, SMF may be used for the transmission distance in excess of 10 miles but will need the use of Laser transmitters. The equipment for single mode transmission more expensive as compared to multimode equipment.
Information carrying capacity = BW *Length
MMSI 20MHz.Km
MMGI 1GHz.Km
SMSI 100GH.Km
For more information you can refer:
Fiber-Optic Communication Systems, 4th Edition. Govind P. Agrawal

[Author]

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