- This topic has 7 replies, 2 voices, and was last updated 8 years, 4 months ago by alistu.
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November 30, 2015 at 5:51 am #28212Dr. Dhiman KakatiParticipant
What is peak to average power ratio (PAPR), how it effect the communication system. If we consider OFDM using quadrature phase shift keying (QPSK) modulation technique it decreases PAPR but when there is a abrupt amplitude variation the higher order terms of the phase modulated signal, will make each data to spread over multiple carrier and it induces a large Inter-carrier Interference (ICI). so how to encounter this problem. Thanks in advance.
Regards,
Dhiman -
November 30, 2015 at 6:52 am #28218alistuParticipant
Hi Dhiman,
As its name implies, it is the ratio of the peak power to average power (which you can set in OptiSystem 13 OFDM transmitter component) in OFDM. OFDM has rather high PAPR. So for a signal with average power, at some instants the power becomes high and this causes problem by letting nonlinear effects to kick in when the signal is launched into fiber.
Regards
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November 30, 2015 at 7:46 am #28221Dr. Dhiman KakatiParticipant
Hi Alistu, Thanks for the reply, So how to handle the problem as you mentioned in the last line, any suggestion please.. ” So for a signal with average power, at some instants the power becomes high and this causes problem by letting nonlinear effects to kick in when the signal is launched into fiber.”
Regards
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November 30, 2015 at 10:11 am #28224alistuParticipant
You’re welcome Dhiman. There have been many suggestions regarding PAPR, but in different systems. For example, I have seen suggestions about MIMO OFDM, some for CO-OFDM, etc. And suggestions include mathematical methods in many cases. If you are interested in any particular area and you want me to introduce a paper, you can let me know. BTW, do you want more explanation about the part of my statement that you have repeated in your comment?
Regards
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November 30, 2015 at 10:04 pm #28237Dr. Dhiman KakatiParticipant
Hi Alistu, The line i put from your reply, I can understand the meaning of it but unable to imagine exactly the scenario, a littlebit expalnation will be helpful. Thanks.
Regards,
Dhiman -
December 1, 2015 at 1:55 am #28244alistuParticipant
As you know, signal with high power being injected into the optical fiber causes signal degradation due to nonlinearities. At the same time, if we send a low-power signal into the line, we may not be able to get the desired BER due to low SNR. So there should be a trade-off. Let’s say we have to launch a signal with average power into the fiber. Now for OFDM, even this average power signal has some instants with high power because of its high PAPR. So for a signal with average power, we might still have nonlinearities in an OFDM system (Of course, the terms AVERAGE, HIGH and LOW are relative) which contribute to signal corruption.
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December 1, 2015 at 4:25 am #28251Dr. Dhiman KakatiParticipant
Thank you So much Alistu for the explanation. Its helping.
Regards
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December 1, 2015 at 6:02 am #28256alistuParticipant
You’re welcome.
Cheers!
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