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Rafael C Lavrado.  Fading Channels  Alternative Representation  PAM Analysis  QAM Analysis  Conclusion.

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Presentation on theme: "Rafael C Lavrado.  Fading Channels  Alternative Representation  PAM Analysis  QAM Analysis  Conclusion."— Presentation transcript:

1 Rafael C Lavrado

2  Fading Channels  Alternative Representation  PAM Analysis  QAM Analysis  Conclusion

3 h(t) x(t) n(t) y(t) y(t)= x(t) + n(t)

4 h(t) x(t) n(t) y(t) y(t)= αx(t) + n(t)

5  Is a Random Variable  Mean Square Value Ω =  PDF dependent on the nature of the radio propagation environment

6  As the carrier is attenuated by α, the signal power is attenuated by  And then we will define the instantaneous SNR per bit by  And the average SNR by

7  Expected value of the probability of error taken over the RV α

8  Rayleigh ◦ Mobile Systems with no LOS path between the transmitter and receiver  Nakagami-m(Rice) ◦ Propagation path consist of one strong direct LOS  Nakagami-q(Hoyt) ◦ Satellite Link subject to strong ionospheric scintillation

9  Log Normal ◦ Caused by trees, buildings- Urban  Nakagami-m ◦ Best fit to indoor mobile

10  PDF  In terms of SNR  MGF

11  General Expression  For M=2

12  Substituting for  If we use the classical representation of the Q function we going to face some difficulties.

13  Classical representation  Alternative Representation Infinite Limit Variable in the Limit

14 Remember

15 : For the Rayleigh Fading channel

16  General Expression  For 4-QAM

17  Substituting for  So now, we need to calculate the integral for Q square

18 Alternative representation for Q square

19 So, = And, = Thus for

20  The alternative form of Q-Function can help evaluate the error probability in Fading channels.


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