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carpa
Joined: 12 Nov 2004
Posts: 78
Helped: 5
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 30 Mar 2006 8:49 Simulation Results Difference? |
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I have simulated a certain wireless communication system in doppler fading channels. However the simulation results (BER vs. SNR) are different from the other books and papers, even the channel parameters and demodulation techniques are the same.
Is this a serious problem, or this kind of difference is popular when channel model( just model, not parameters such as doppler frequency or delay profile) is different from each other.
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Sal
Joined: 29 Nov 2005
Posts: 288
Helped: 36
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| 31 Mar 2006 0:07 Simulation Results Difference? |
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Hi
It depends how different are your simulations and how different is the channel model you are using, if the channel model is the same, you should get the same plot which is in the books and papers, otherwise there si something wrong with your simulations. This difference is very important depending where you are submitting your results, if it is a paper, your results need to be confirmed very well
cheers
Sal
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bts_dev
Joined: 04 Mar 2006
Posts: 154
Helped: 84
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| 01 Apr 2006 5:14 Re: Simulation Results Difference? |
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If u r sure that the channel parameters & the mod/demod is identical - then u may be doing the most common mistake ppl do - viz incorrect way of adding noise.
I d advise u to look closely at reference graphs & if they say that its a curve of Eb/No v/s BER... then see to it that adding noise as per given SNR to the o/p symbols of the tx chain is INCORRECT.
As channel SNR -> Ec/No(dB) = Eb/No(dB) - Modulation Gain(dB)
Here Eb -> Unmodulated bits &
Ec -> Modulated symbols passed through channel.
PS: Do lemme know if it was of any help
cheers
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carpa
Joined: 12 Nov 2004
Posts: 78
Helped: 5
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| 03 Apr 2006 4:12 Re: Simulation Results Difference? |
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I have carefully calculated the relation between SNR and Eb/N0, and currently because I simulate an OFDM system and I only use SNR on the receiver anttenna as the x-asix of the plot. I have already normalize the power of the wireless multipath channel to 1.
In the paper for comparision the detail of the channel model was not described clearly, although parameters were given such as doppler frequency and delay profile. I think the simulated different is caused by the different channel model.
Is that right?
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Naveed Alam
Joined: 06 Jan 2006
Posts: 280
Helped: 16
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| 10 Apr 2006 9:45 Re: Simulation Results Difference? |
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share ur code or portion of ur code,,,
regards
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