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  1. #1
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    BER for OFDM using QPSK & Convolutional Encoding

    Hello,
    I have tried to simulate the performance of an OFDM system using QPSK a rate 1/2 convolutional code and a Viterbi decoder at the receiver. The problem I face now is after plotting the results, I come up with a funny graph that doesn't look anything like the theoretical result.
    Here's an attachment of the MATLAB image i obtained.

    Can anyone possibly tell me where I have gone wrong in this code?

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  2. #2
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    BER for OFDM using QPSK & Convolutional Encoding

    umm... there is no code only a graph.

    Here is what might have gone wrong.

    1) less number of samples transmitted (monte carlo requires a good number for accuracy)

    2) noise not generated properly

    Also, I don't find the graph to be funny



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  3. #3
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    Re: BER for OFDM using QPSK & Convolutional Encoding

    Thanks for your reply. I suspect my problem is with the noise generation, I have used the inbuilt matlab function to genrate awgn noise y = awgn(x,snr).
    Is there another way of generating noise apart from this?

    I can post the code if it will help.

    Thanks again



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  4. #4
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    Re: BER for OFDM using QPSK & Convolutional Encoding

    actually i got a model with desired graph, but the problem i av is after adding the convolutinal encoder and interleaver at the transmitting side, and viterbi decoder and deinterleave rat the receiving side, i was givin a block error, pls hw do i go by it. I can send the model to you let me know by sending me mail on omotayour06@yahoo.com.
    Also kindly help me attach your simulink model to the email too.



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