land mobile satellite channel model

[imported_dexter]

hallo forum, I have a problem in doing my final task in land mobile satellite's channel modelling.
I still do not understant what's the effect of doppler to graph of BER or FER to Eb/No in satellite UMTS' rician model that's placed in LEO.
May I get the formulas ?
tanks a lot.

[Will.Spencer]

Originally Posted by dexter

I have a problem in doing my final task in land mobile satellite's channel modelling.

Ohhh... that explains the odd questions over the last few months!

Originally Posted by dexter

I still do not understant what's the effect of doppler to graph of BER or FER to Eb/No in satellite UMTS' rician model that's placed in LEO.

First, let's describe a few of these terms for other forum members. This post has got to be harder to read than the recent threads in Spanish and German. :p

The Doppler effect is the apparent change in wavelength and frequency of a wave when the sender and receiver are in motion relative to each other.

BER is Bit Error Rate. This is the percentage of bits that fail to transmit properly.

FER is Frame Error Rate. This is the percentage of frames that fail to transmit properly.

UMTS is Universal Mobile Telephone Service, a standard for 3G cellular phone service.

Eb/No is Energy per Bit (Eb) to the Spectral Noise Density (No). Eb/No is used to quantify Signal to Noise Ration (SNR) across different communication technologies.

The Rician Model is a formula used to describe fading on line of
sight signals.

LEO is Low Earth Orbit. LEO satellites fly close to the Earth, and are not geosynchronous.

Originally Posted by dexter

May I get the formulas?

Which formula are you looking for? The Rician distribution formula?


Where:

v is the ratio of received voltage relative to the direct path
K is the ratio of direct to multipath power received and is a constant
I0( ) is the 0th order modified Bessel function of the first kind.

If you're in a course, shouldn't the necessary formulas be in one of your coursebooks?

[imported_dexter]

Tanks to Mr.Will Spancer for your answered.

But sorry sir I just had red your replay of my question about rician channel model for land mobile satellite, and I still confused.
As red from this site that the velocity problem in this orbit are from user movement's velocity and satellite velocity it self. And from the theory's said that as the increasing of both velocity will cause larger doppler that will effect of increasing required Eb/No to get the same BER value.
From the theory I can conclude that both velocity will effect Eb/No required.
But I still cannot get, what is used of rician model in this theory? And what formula that show the velocity will effect required Eb/No and BER?
Do you have any refferences that I can use to support my final task?

Tanks a lot

[Will.Spencer]

Originally Posted by dexter

I still confused.

Me too! This stuff is hard.

Originally Posted by dexter

As red from this site that the velocity problem in this orbit are from user movement's velocity and satellite velocity it self. And from the theory's said that as the increasing of both velocity will cause larger doppler ...

I concur.

Originally Posted by dexter

...that will effect of increasing required Eb/No to get the same BER value.

That seems a little off. You don't really increase the Eb/No. You may increase the power, but the Eb/No is an effect, not a cause.

Originally Posted by dexter

From the theory I can conclude that both velocity will effect Eb/No required.

Same comment as above.

Originally Posted by dexter

But I still cannot get, what is used of rician model in this theory?

The Rician model is used to generate an estimate of fading loss in line-of-sight transmissions.

Thinking this through, it appears to me that the Rician model does not take the doppler shift into account and that you much therefore account for it seperately.

Originally Posted by dexter

And what formula that show the velocity will effect required Eb/No and BER?

I still have the same comment as above regarding Eb/No.

Required BER is defined by your application, by the user, and by business needs. It's not a technical decision.

But the formula to estimate this... that's the real question!

I think you may have to add in the Doppler Shift something like this:


where v is the speed of the receiver in relation to the sender.

Originally Posted by dexter

Do you have any refferences that I can use to support my final task?

Try these:

• Radio Propagation Models
• Overview of Fading Channels
• Eb/N0 Explained

Has your instructor discussed the Raleigh model with you? It's like the Rician model, except that it is designed to model fading loss over multipath distribution.