Calculation/Simulation Error

[Irfan Morshed]

Hi everyone,

This is my final project on 3 user SAC-OCDMA project. My college work is due in a few days .. However, it is not running/cannot be calculated.

Can somebody please be kind enough to solve it for me?

Why cannot it be calculated? Everything is alright here apparently.

[alistu]

Hi Irfan,

This file is OptiSystem SAC-OCDM sample as far as I am concerned (so you can find it in OptiSystem samples). I ran the simulation and it went smoothly with acceptable results except for the third user (which you should first enable in the simulation BTW). If you cannot open the file or do the calculation, this is a technical issue and you should contact Optiwave, which will probably answer after the weekend.

I suspect something might be wrong with the way the third code is generated by FBGs. I haven’t worked much on SAC-OCDMA, but if you are interested to know how the codes should be generated, I suggest you thoroughly go through the related comprehensive discussion in the link below:

how to implement sac ocdma?

Regards

[Irfan Morshed]

Sample file? I got that file from the discussion link you shared, and it seemed to be Miss Kaurs completed thesis work.

Anyway, my project basically is for 3 users, sending 1010, 1100 and 1001. Can u check my encoding and decoding algorithm? I used complementary/balanced detection.

So we have 4 wavelength values –

lamda 1 = 1550 nm
lamda 2 = 1550.8 nm
lamda 3 = 1551.6 nm
lamda 4 = 1552.4 nm

Walsh code for Encoding :

User 1 (1010) : 2 FBGs at encoder coded with lamba 1 and lamda 3 (lamda 2,4 are cut off)
User 2 (1100) : 2 FBGs at encoder coded with lamba 1 and lamda 2
User 3 (1001) : 2 FBGs at encoder coded with lamba 1 and lamda 4

Walsh code for decoding using complementary/balanced detection :

User 1 (1010) : 2 top FBGs at decoder coded with lamba 1 and lamda 3, 2 bottom FBGs at decoder coded with lamba 2 and lamda 4
User 2 (1100) : 2 top FBGs at decoder coded with lamba 1 and lamda 2, 2 bottom FBGs at decoder coded with lamba 3 and lamda 4
User 3 (1001) : 2 top FBGs at decoder coded with lamba 1 and lamda 4, 2 bottom FBGs at decoder coded with lamba 2 and lamda 3

That sounds logical?

[Irfan Morshed]

Brother, I will only get access to optisystems on tuesday.

I checked with others. For my project with 3 users, the algorithm that I wrote above is correct.

So for each user, I will have 2 FBGs at encoder side, and 4 FBGs at decoder side (for complementary detection/ 2 Top and 2 bottom FBG arrays). If possible, could you please be kind enough to just edit that osd file and instead use 2 FBGs for each user at encoder side, and 4 FBGs for each user at decoder side using the wavelength values that I mentioned? And white light source frequency should probably be the center frequency (1550.8 nm).

If it runs after this work, then my project will be successful. Its due in a few days and I have no access till tuesday.

Its just 5 minutes work for u.

Please be kind enough to help this little brother out.

[Irfan Morshed]

I am entirely helpless and I have nobody to help me.

My work is due in a few days and I am already having panick attacks.

[Irfan Morshed]

User 1 FBG connection attached below.

[Irfan Morshed]

Or if u want, u can make user 3 work somehow in that osd file.

But if u use my coding as mentioned above, it should give the right result. I do not have access till tuesday.

Please help out.

[alistu]

Here are screen shots from each of the 3 users BER analyzer. The third user signal is probably corrupted, so the BEr analyzer does not show anything. I will let you know in case any progress will be made in making it work.

[Irfan Morshed]

Okay thanks. Could u please tick the checkbox : “Show Eye Diagram”, and send me eye diagram for user 1 or user 2 please.

I needed the eye diagram actually more.

[alistu]

Here they are.

Regards

[Irfan Morshed]

Thanks a lot. Which version are u using bro? v 13?

The file does not open from version 14 for some weird reason.

I thought optisystems was backward compatible!

[Irfan Morshed]

I installed version 14 from online.

And it gives me this error on calculating entire project.

What the hell .. how can version 14 be this screwed up!

[Irfan Morshed]

I think this is the final solution.

Bro, kindly run this one and hopefully this should give us the expected results.

Does it run and give the proper results for the 3 users?

[Irfan Morshed]

final one.

[alistu]

Yes, here’s the screen shot from all users.

BTW, did you try to change the FBG frequencies to make it work?

[Irfan Morshed]

Bro,

I cannot access it because it does not open from optisystems version 14! That is why I requested you to kindly change the FBG wavelength and make it same as the one I gave above.

For each user – 2 FBGs for encoder, 4 FBGS (2 top, 2 bottom for complementary subtraction) at decoder.

This is the file. I think you helped Miss Kaur with it already.

And if you cannot change it, can you please let me know if the attached file works/runs or not?

[MHD NA]

This file is OptiSystem SAC-OCDM sample as far as I am concerned (so you can find it in OptiSystem samples). I ran the simulation and it went smoothly with acceptable results except for the third user (which you should first enable in the simulation BTW). If you cannot open the file or do the calculation, this is a technical issue and you should contact Optiwave, which will probably answer after the weekend.

[Dr. Dhiman Kakati]

Hi Irfan, the error is because of the wrong “power ratio array” at the component properties of power splitter. there should be as many ones as the no of outputs. Thanks

Regards,
Dhiman

[Irfan Morshed]

Dhiman,

Brother could u please correct the error and send the corrected osd file to me? I do not know how to fix it!

Please.

[Irfan Morshed]

As mentioned by Mr. Damian earlier, since I am upconverting 2.5 GHz signal to 60 gigs, he said I would need 8192 samples per bit. So I have made the changes and improved signal filtering, and added all your suggested corrections.

This time, the project is taking hours to calculate. I cancelled calculation after it exceeded over 2 hours!

Osd file attached.

May I kindly know what is the issue with this one?

Please help out guys! Submission is next week only .. 🙁

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