32QAM low BER value

[Lukas Koritar]

Hi,
I am trying to make non coherent 32QAM moduloation for FSO (I have attached the file) but value of BER is too low (0,5) and eye diagram seems strange. I’m amateur with Optiwave, so I don’t know where can be mistakes. Could you help me, please? Thank you.
Reagards
Lukas

[Aabid Baba]

Hi Lukas,
What power have you taken for transmission in your system. As far as i know the power required for transmission has to be very high because of the surroundings in which the optical signals have to travel wirelessly. I cannot open the file right now because we have access to tool in working hours only so i would suggest you to look at the power.
regards

[Lukas Koritar]

Hi Aabid,
I have set power 5mW, FSO distance 1km with 0 dB/km attenuation because we have at university simulation box for create atmospheric effects (lenght 5 m) and I have to try simulation in Optisystem but I have null experience with Optisystem. So I have tried change bit rate and symbol rate but still the same results. Thanks.
Regards

[Aabid Baba]

Hello Lukas,
As far i am concerned, You can increase power upto 15mW in free space optical communication link. I had provided you with a link of ITU-T standardization..Did you check it???
It provides you an essential set up parameters for your free space optics designs. Shall check your osd file in working hours tomorrow.
For now i suggest you to increase power at source and use optical amplifier instead of EDFA if you are using one.
Hope it is helpful.
Regards

[Lukas Koritar]

Hi Aabid,
Yes, I did. I have tried to increase power upto 15mW but still the same. Is good to use BER Test or not? I will be very glad if you are going to check this tomorrow. Thanks.
Regards

[Aabid Baba]

Hello lukas,
i shall definitely check your osd file tomorrow. I hope i will be able to provide you with some help.
Is it necessary for you to use QAM modulation scheme for your system??

regards

[Lukas Koritar]

Hello Aabid,
Thank you very much for your interest to help me. Yes, I need QAM and as well PSK because I’m working with these modulations schemes at laboratory at school and I have to simulate also. Thanks.
Regards

[Aabid Baba]

Hello lukas,
I was just trying to run your system design. Although i couldn’t understand what exactly you are doing because of the complexity of your design but i guess it has got something to do with test set. I would like to suggest you to go through some of the examples in the optisystem samples regarding using the test set.
Also i tried to change your data rate which was in Mbps into Gbps. There is some logical error you are doing.

Regards

[Lukas Koritar]

Hello Aabid,
Thank you. I will try to change some parameters and i hope that the results will be better than now.
Regards

[Aabid Baba]

hello Lukas,
I am sorry i couldn’t do anything but definitely you results get better if you try to improvise some things in your system design and some parameters..I hope your problem will get resolved soon.
best regards

[Lukas Koritar]

Hello Aabid,
Do you know where I could find any example such as 8PSK or 16PSK or dot you have any similar project examples? Thanks
Regards

[Aabid Baba]

Hello Lukas,
As far as i know there are number of examples given about different modulation schemes which include 8PSK 16PSK and so on..
You may refer to the optisystem sample folder where under folder name ” advanced modulation systems” you will find your requirement. For your convenience let me upload .osd files for same.
Please find them herein.
Regards

[Lukas Koritar]

Hello Aabid,
Thank you for files. I have looked to examples folders but we haven’t this files and I don’t know why. Once again thank you, i will look at it.
Regards

[Aabid Baba]

Hello lukas,
Actually these are the updated osd files from optisystem 14. May be that is the reason but i remember them to be there in optisystem version 13 as well. Anyway , you are welcome and discussions are always welcome.

Best regards
Aabid

[Lukas Koritar]

Hello,
I’ve looked again and we have examples only in directory Optisystem 12 and in Optisystem 14 isn’t any examples. I’Ve attached screen with qam examples which I have. Are examples in version 14 different or better? It is pity that 8PSK and 16PSK above are coherent detection. Thanks
Regards

[Aabid Baba]

Hello Lukas,
I want to mention that in optisystem 14 examples based on advanced modulation systems are quite high in number and almost on every modulation scheme be it QAM , PSK , QPSK and so on…
I think you should update to 14 if possible or if you want i can upload all the osd files you require. Feel free to ask i would definitely upload all of them/

Regards

[Lukas Koritar]

Hello Aabid,
We have version 14 but I see examples only from old version (12). If it possible upload all files i will be glad. Thank you very much! 🙂
Regards

[Aabid Baba]

Hello Lukas,
yeah sure i am glad to help you.
Please all the files herewith. I am attaching each and every file contained in that folder. I hope it would help you.
Regards

[Aabid Baba]

rest follow herein. Find the attachments

[Aabid Baba]

Rest follow.
These two files are under the folder name PAM systems. The files are under the folder name OFDM systems as name would suggest when you open the files. I shall upload other files too but in next post to avoid merging of osd files so that it is easy for you to differentiate.

Regards

[Aabid Baba]

Hello Lukas,
First two files are under the folder name BPSK systems.
The next following files are under the QPSK folder. I hope you would be able to ease things for yourself.
Regards

[Aabid Baba]

Hi Lukas,
Please find all the attachments herewith. I hope it will definitely be easy for you now to go through different examples and somehow improvise with your system design.
Please Also check the last attachment it is about the free space optics and it might help you to a large extent in understanding your then required parameters and all other necessary changes. I hope this helps.
Regards and Best wishes!

[Lukas Koritar]

Hello Aabid,
Thank you, I’m grateful to you. It is too many examples 🙂 I will look at it and maybe i will find some mistakes with my project.
Regards

[Aabid Baba]

Hello lukas,
you are welcome. Please do check the last attachment which was about implementation of an FSO system. I am sure if you would try to simulate it , you will definitely get an idea about the simulation set up of FSO and also different coding schemes and components used. I hope you will troubleshoot your problem
Regards

[Lukas Koritar]

Hello Aabid,
I was trying this example (https://optiwave.com/resources/applications-resources/optical-system-digital-modulation-dpsk/) according files which you’ve attached (DPSK Step xx) and if I run the project, the output behind DPSK sequence decoder is zero (I made screen, I’ve attached screen below). Maybe the same error will be in my 32QAM project that output behind decoder is all zero.
Regards

[Aabid Baba]

Also i would suggest you to increase the symbol rate in the simulation layout parameters (keep it more than the bit rate itself). Improvise use of components like increase bandwidth of MUX, filters if you are using any. For your convenience i will attach a link which you can refer to and simulate accordingly. Hope it helps.
http://www.itu.int/ITU-T/newslog/Free+Space+Optics+Standards+Start.aspx
Regards

[Ranjeet Kumar]

Hi Kukas,
Use BER nalyser in place of BER test set and i think to increase BER you should decrease the no. of bits in QAM. You should also vary the Laser power in order to optimize the results.

[Tanveer]

hi Lukas,,,,
the osd file you have attached seems to have some problem while opening in my optisystem 14, however it is not showing any error messages the optysystem, it opens and then closes by itself…
with regards

[Lukas Koritar]

Hello Tanveer,
I have attached osd file again below. Is it working now?
Regards

[Aabid Baba]

Hi tanveer,
It works fine with optisystem 14.

[SAHIL SINGH]

hi tanveer,
As mentioned by abid it works fine with optisystem 14

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