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  1. #1
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    Why we use the awgn channel for analysing the performance of communication systems?

    Hi i would like to know why we most of the times use the awgn channel for analysing the performance of the communication systems....
    Thanks in Advance...

    •   Alt10th September 2007, 17:44

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    Re: awgn channel...

    There isn't ideal communication channel since this noise, AWGN, is always be in every communications channel.


    Br,



    •   Alt11th September 2007, 02:00

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    awgn channel...

    hi,

    AWGN is consist of four words (Additive-White-Gaussian_Noise). Now we should ask about each of the first three words.

    why additive?!
    there are two main reason:
    1- A receiver antenna is almost always a linear device, so have superposition property. the two sources with different natures (desired signal & noise) are received at the received antenna, independently. so following superposition property, the output of the antenna is the addition of signal and noise.
    2- it is accommodated with the experiments.

    why zero mean white noise?!
    it is zero mean because the noise hasn't any polarity. the probability of the noise to be positive is exactly equal to the probability of noise to be negative. and it is white because the most power of the noise are thermal noise and this kind of noise is white in a broad range of frequency.

    why Gaussian?!
    according to central limit theory sum of many phenomena with different natures are Gaussian that is what we have in communication systems.

    so this model is well appropriate with real noises in data communications.

    regards



    •   Alt12th September 2007, 10:21

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    Re: awgn channel...

    Thanks..

    What is difference between AWGN and Rayleigh channel..

    Which one popular in MIMO Technology.



  5. #5
    Sal
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    awgn channel...

    Hi

    your questions are kind of basic, I recommend you read more in wikipedia, because the the topic is more broadly covered and gives you a better overview of the topic http://en.wikipedia.org/wiki/Rayleigh_fading

    good luck

    sal



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