Respected Researchers, I need to know the difference between path loss of mobile-satellite links and mobile to mobile -mobile links.
1.If i write received signal as r given by r=h*((d)^-alpha)x+n will it be correct to write such equation for satellite to fix mobile station links.where h denotes shadowed rice distribution, x is signal , and d^ -alpha denotes distance based path loss effect. as you know the distance between(slant range) LEO satellite is variable. can i take d equation for elevation angle as variable.
2. similarly for mobile to mobile channel i have r=h1*((d)^-alpha1)x+n here h1 represents nakagami-m or rayleigh channel and d denotes distance based path loss. please guide and advise whether both equations are correct to write because in most papers i have not seen any d^ path loss exponent factor.
3. if I write most people write r=sqrt(E) h1*x+n. How to relate E to distance because in my case for LEO slant range is changing.
4. Lastly How to combine path loss distance dependent factor in one network i.e in hybrid satellite-terestrial network. i.e in satellite-mobile-mobile
i.e r=h1*((d_satellite)^-alpha1)x1+h1*((d_mobile)^-alpha2)x2+n will this equation is correct. we have very large distance between satellite-mobile(d_satellite) path as compared with mobile-mobile(d_mobile) .
Any help How relate these distance with power of signal or SNR .
Most regards
Well your equations for both type of channels are theoretically correct. But what most researchers in this area do is write the equations for path loss and small scale fading(h) separate. The large scale fading is required to deduce the power required to send the signals to the receiver while small scale fading gives us the measure of how the receivers and transmitter modulation and coding should be designed.
Anyways in satellite network the slant range is important. So the alpha factor has to be related to the slant angle. You will find some relation in satellite communication books. So alpha = f(slant angle).
Your equations for hybrid network is also correct. You can elaborate your equations to include other effects as well from the attached papers specially for satellite to mobile communications.
At the frequencies of communication used by sat-to-mobile and mobile-to-mobile, almost line-of =-sight is needed. Also, multipath fading can be severe is certain multipath environments. For example, the original cell phones did not work well in the middle of New York City. Theoretical and practical information on multipath fading should help you understand and design a robust comm link. Theoretical signal propagation can be affected by signal absorbtion. I am not a fan of modifying the equations of physics by using artifical means like changing the exponent of the inverse square-law relationship. I believe research and design engineers should learn the basic physics behind all of this. Good luck
Sir Russell. Thanks for your comments.will you please elaborate your point ,how to include effects/factors of satellite-mobile channel using physics. Can provide some examples in order to understand. if you provide equation which explain this behavior ,i shall be very grateful
For mobile-mobile path the lower atmosphere and terrestrial effects can be seen
For mobile-satellite path the effects of all layers of atmosphere along the path can be seen
Also the chosen frequency, modulatıon techniques and polarisation are important
Madam Yazgan ,thanks for your answer,I need to ask two two questions
1.will you please email some related literature ,papers which explain some effects of different atmospheric layers between mobile and satellite links.
2. What is significance of adding polarization RHP,LHP. I just know that these polarizations are being used for MIMO channel.Can you tell How to incorporate these ploarization in r=hx+n, I shall be very grate ful
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