# Conceptual Question on equalization technique in rayleigh fading channel based on a paper

gives theoretical expressions for BER in Rayleigh fading channel. Can I use the expression for 64-QAM in this paper? The Authors have given a plot of the BER performance but there is no expression for it. So, I am unsure how to get the plot for Rayleigh case.

1. The model they have used is general and you can apply it to QAM as well.

2. In wireless communication systems, channel and noise are two different impairments affecting the overall transmission. Here as everywhere else, the noise is AWGN (additive white Gaussian; if you want to know what these terms mean, see this article). And the channel is a linear filter with taps whose magnitudes are modeled as Rayleigh random variables.

3. Yes, you can use the expression in that paper. The authors didn't give the expression because they might not have known it and simply generated it from Monte Carlo simulations.

• Thank you for you reply. Could you please elaborate more on how to construct the multipath with the delay profile of 0,-3 and - db and 64 QAM modulation in general (not necessarily using the chaotic signal as the input) because it is not quite clear to me how to model QAM symbols with Rayleigh impulse response. Shall really appreciate your time and effort.
– SKM
Oct 24 '16 at 5:23
• Generating QAM symbols is separate from generating a Rayleigh fading multipath channel. For your purpose, you can generate a multipath channel as in the following article: dspdotcomm.blogspot.com.au/2008/11/…
– QMC
Oct 24 '16 at 5:33
• Thank you for the link. Just to confirm if my understanding is correct, after I model the channel as RAyleigh r.v I should apply the QAM modulation technique. Is this correct? But what analytical BER expression should I use?
– SKM
Oct 24 '16 at 6:46
• Thank you for the link. Just to confirm if my understanding is correct, after I model the channel as RAyleigh r.v I should apply the QAM modulation technique. Is this correct? I can still apply the expressions of the estimator in the paper
– SKM
Oct 24 '16 at 6:58
• But what analytical BER expression should I use?
– SKM
Oct 24 '16 at 6:59