- This topic has 21 replies, 4 voices, and was last updated 9 years, 4 months ago by
Ashu verma.
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July 12, 2015 at 9:26 am #22349
Gurpreet KaurParticipantWhat is the maximum value for transmitter and receiver aperture diameter in OWC, that can be used considering Cost an important factor?
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July 13, 2015 at 1:55 am #22358
Abhishek ShramaParticipantIn Inter satellite communications, antennae aperture diameters have always been an important factor as it decides the cost effectiveness of system. System payloads decrease with smaller size of antennae reducing its weight and hence launching cost.
There have been a lot of work in this arena.
There is no such constraint limiting the size of antennae.It depends upon beam divergence, whether your system is unidirectional or bidirectional, and the distance the signal is traveling as size of antenna at receiving side is usually taken more than transmitting side(due to beam divergence reasons).
A lot of work is done in arena. As per my knowledge the results achieved till now is 15 cm or 150mm. Rest it depends upon how long you want link to operate.
In normal system it have reduced by various parameters and trade-offs from 50cm in earlier researches to 15 cm in latest ones. Find the attached links. -
July 13, 2015 at 8:56 am #22377Gurpreet KaurParticipant
Thanks Abhishek.
But in most of the research works the aperture diameter is taken upto 60cm. So this is going to increase the cost.
can you tell me if any other factor than cost is affected with larger apertures? Any disadvantages of using large diameters? -
July 13, 2015 at 10:24 am #22382
Ashu vermaParticipantHello Gurpreet Kaur
I Agree with the explanation given by the Abhishek,The paper and links given above are good.It is general trend in optical wireless channel that with increase in the size of the aperture diameter for both transmitter and receiver,the quality of system increase.However there is disadvantage of large aperture diameter which are cost of the system and designing the whole satellite .As there are many issues related to satellite design,if large the aperture diameter more bulkier the whole setup.Rest you are not considering that facts and simulate the system with upto 50 cm of aperture diameters. -
July 13, 2015 at 11:32 am #22390Ashu vermaParticipant
To add above discussion ,i have attached the link of the paper that i found very important and explain almost all the technical challenges to design OWC. This article explains considerations of the orbit and spectrum for the use of terminals over geostationary satellites as well as considerations on antenna-pointing errors, effects of rain fading, and effects of interference
on adjacent satellites -
July 13, 2015 at 12:57 pm #22391Gurpreet KaurParticipant
hello,Sam sung
The link you attached is related to satellite communication on the move system terminals(SOTM). things are not much clear to me. -
July 14, 2015 at 3:03 am #22401Abhishek ShramaParticipant
Hi! SAMSUNG
I agree with Gurpreet Kaur,the link you have provided no doubt it has very good content regarding SOTM.But the discussion is here about the ISOWc communication.Rest gurpreet kaur can you please elaborate your objectives? -
July 14, 2015 at 10:22 am #22407Ashu vermaParticipant
THank you Gurpreet Kaur and Abhishek sharma to clear the main area of concentration.Please share the objectives of your work for better information.
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July 15, 2015 at 4:38 am #22432Gurpreet KaurParticipant
i was planning to implement spatial diversity for improving the performance of IsOWC. but i am not sure about whether this approach is beneficial because it might make the satellite bulky
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July 15, 2015 at 6:01 am #22437Abhishek ShramaParticipant
From what I can grab from your discussion is that your objective must be designing multiple Tx/Rx systems.Multiple transmitters/receivers (TX/RX) are used to improve the quality of intersatellite optical wireless communication system.
check the link. I think you can very efficiently relate it to your objectives.
http://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCMQFjAAahUKEwii4ZHt79zGAhXBJKYKHUc0BTQ&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6148721&ei=qy6mVeLfLsHJmAXH6JSgAw&usg=AFQjCNEfuQH6DxR9nNdyNkqcINeCUhTRXQ&sig2=96LsSl7Ber4vfF6tUUQvbA&bvm=bv.97653015,d.dGY -
July 15, 2015 at 6:44 am #22447Abhishek ShramaParticipant
As you are in dilemma, that whether the approach is beneficial or not the you can check a number of papers on multiple transmitter and receivers
for study of isowc with multiple tx rx in detail goto:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CC4QFjACahUKEwjOudbr-dzGAhXFIqYKHW_8BiU&url=http%3A%2F%2Fportal.fke.utm.my%2Flibraryfke%2Ffiles%2F219_AIDAHASFIZABINTIHASIM2009.pdf&ei=JTmmVY6TA8XFmAXv-JuoAg&usg=AFQjCNG_oJ1ekig8GTI7mWT2P3CUqq8QYg&sig2=Jkv0xy3lnwPY_EUpL7a1YQ&bvm=bv.97653015,d.dGYtell me if still you need any help.
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July 15, 2015 at 9:15 am #22460Ashu vermaParticipant
Hello Gurpreet Kaur
Links attached by Abhishek sharma are pretty good if you are looking for multiple Tx and Rx systems.I found this paper very helpful to study
http://www.ijert.org/view-pdf/287/performance-improvement-of-intersatellite-optical-wireless-communication-with-multiple-transmitter-and-receivers -
July 16, 2015 at 4:27 am #22491
ahmed helmy teamaParticipantGurpreet Kaur, in addition you should observe From eye diagrams, the value of Q factor and Minimum BER are taken up to BER < 10-9 to achieve an error free communication, as this is the limit up to which successful communication can take place.
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July 16, 2015 at 4:38 am #22492Gurpreet KaurParticipant
thank you everyone. i have implemented the system with 4 TX/RX. no doubt the BER and the Q factor are getting improved with this approach till 5000km. but if i am increasing the distance beyond that, with aperture diameter value 18 cm, for both transmitter and receiver, then the BER is not in acceptable limits.
so if i increase the aperture diameter say to about 25cm, then the system is improved. but this is going to increase the cost of the overall system and make it bulky too as abhishek and sam sung said above.
so i am not sure to implement this.
please suggest me whether this approach is good or some other option for improving the system at increased distance. -
July 16, 2015 at 5:50 am #22493Ashu vermaParticipant
Hi Gagan
You can go for some advanced modulation formats rather than increasing aperture diameter.Qpsk would be the good choice for didtance enhancement because it can support high data rate as well as bandwidth efficient.your covered distance depends upon your bit rate ,higher tge data lesser the covered distance.There is discussion on forum on the sane topic for the use of QPSK in isowc system.find the link -
July 17, 2015 at 2:17 am #22519Gurpreet KaurParticipant
thank you.
i am using optisystem 7. can anyone send me the simulation setup for qpsk modulation and demodulation for this version?-
July 17, 2015 at 9:15 am #22525Ashu vermaParticipant
go through this discussion
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July 17, 2015 at 3:22 am #22521Ashu vermaParticipant
Hi Gagan
As far as i know you cannot make qpsk in older version.To use qpsk you have to switch for latest version of optisystem.Qpsk Dsp in latest version is very simple to use in effective way.you can download a trial version for 30 days from this website.I am sure regarding the thing that qpsk in optisystem 7 is not possible to design. -
July 18, 2015 at 3:02 am #22532Gurpreet KaurParticipant
thank you sam sung. actually i was working on version 13 only but my license expired so i shifted to version 7.
so its not possible to implement qpsk modulation in 7? -
July 18, 2015 at 3:24 am #22533Ashu vermaParticipant
Hi gagan ,you cannot implement qpsk on optisystem 7.But you can take it on monthly lease from optiwave.Ask bryan for this if you are interested.
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July 18, 2015 at 3:30 am #22535Gurpreet KaurParticipant
ok thank you.
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July 19, 2015 at 8:13 am #22557Ashu vermaParticipant
Welcome Gaganpreet kaur
Best of luck for your work -
January 25, 2018 at 7:18 am #47496
sreevani vParticipantHi sir,
I am working on inter-satellite optical wireless communication using QPSK modulation technique with OPTISYSTEM 15.i am getting the result of each stage at transmitter but am not getting result at receiver.the result is not showing in BER analyser.
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