WDM QPSK THROUGH FSO LINK

[Deepanshu sharma]

hello,

As we know QPSK provides the spectral efficiency of 2 bits/sec/hz. I simulated a WDM QPSK for wireless FSO link but it is providing much more spectral efficiency. please check the attached file and let me know if any updation needed.

Regards,
Deepanshu Sharma

Attachments:

1. qpsk_WDM.osd

[Ashu verma]

Hi Deepanshu,As QPSk has 2 bits per simble i.e it is used for more data rate and more efficieny.Also Bandwidth efficient technique.As far as your system is concerned i will check it.You can also check the new system introduced by optisystem .

100 Gbps DP-QPSK System with Digital Signal Processing

you can use BER TEST set instead of eye diagram visualizer.

[Ravil]

Hi Deepanshu sharma,

I am not able to open your attached file. Do you have a chance to upload a screen shot of your scheme so I can take a look at it and try to answer your question?

[Deepanshu sharma]

hi Ravil,

can u help me what is the achievable spectral efficiency till now for qpsk. actually i am getting a max of 0.5 bits/sec/hz through wdm qpsk based on constellation diagram. i am not calculating the fruitfulness of the receiving signal through BER analyzer because its not appropriate for advance modulation schemes and not BER Test set because it will not helpful for high data rate due to its limitation regarding Bits. It will be a great help if you can help me to enhance its spectral efficiency. please check the attachment

[Damian Marek]

Hi Deepanshu,

How are you calculating the spectral efficiency? Is there a specific equation you use?

Regards

[Deepanshu sharma]

hello Damian,

for spectral efficiency, i am just using the basic formula i.e., bit rate divide by the spacing between the transmitters.

[Damian Marek]

Your constellation diagram is quite messy from the receiver. I think the channel spacing is a bit too close and the signals are overlapping. I don’t think your resulting spectral efficiency is correct because the SER is quite high.

[Deepanshu sharma]

hello Damian,

This is not my exact project.. i am using some new technique to provide orthogonality to the transmitter separately.. u can check the two files attached below where i am able to get a good constellation after using my technique format.but spectral eff is just 0.6 bits/s/hz. the question is how i can improve its spectral eff more.

Attachments:

1. 

   qpsk_vy.png
   

2. 

   qpsk_ortho.png
   

[Damian Marek]

Ah ok! Without any knowledge of your modulation scheme it is hard to say, but perhaps polarization multiplexing could increase it more.

[Deepanshu sharma]

hello Damian,

can you please provide me some links or some file related with polarization multiplexing for the same.

Regards

[Gurpreet Kaur]

I am working on DWDM FSO. can anyone suggest me some papers for the same or give me the simulation diagram?

[Author]

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