Is there some kind of formula for a Doppler spread?

I need to make a model of the Doppler effect at Matlab. The Doppler shift have done. Now it's need to make a model of Doppler spread, but I can't find a formula, which describe it.

Please, could you help me? May be I missed some good articles...

I will be glad to any your help: articles, formulas, models (Matlab code), etc...

[Swarali Sarangdhar]

Hey did you find it ? actually im doing something similar and have stuck on it.

Answer 1

[Jan]

This is a very general questions and an exactly matching answer is unlikely. The more specific a question, the easier is it to answer.

Did you read http://en.wikipedia.org/wiki/Doppler_effect and http://en.wikipedia.org/wiki/Fading already? You cannot calculate a Doppler spread without having a model of the obejcts, which emit the signals. There can be relativistic effects also. So please post more details.

[Alex]

Okay, let's start.

My task is: create a model, which simulate the Doppler Effect. I have a signal ("sin"). I should add the Doppler Effect to this signal.

At this moment I have done:

1) Doppler shift.

I've added it by this formula: http://picturepush.com/public/12446817 (it was taken from that article: http://alephfiles.rtu.lv/TUA01/000034855_e.pdf {pages 74-75}). So, I simply calculate the Doppler maximal frequency shift, then I add it to frequency of my signal.

2) Doppler spread.

I used this ralationship between Doppler spread and Coherence time: http://picturepush.com/public/12446872 (it was taken from that article: http://en.wikipedia.org/wiki/Fading ). The "Tc" I've calculated by http://picturepush.com/public/12446903 (article is: http://en.wikipedia.org/wiki/Coherence_time_(communications_systems) ).

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So, I calculated the Doppler maximal frequency shift, then I calculated the Doppler spread (by using Coherence time), then I added it (Shift and Spread) to my signal.

My chief told me, that Doppler spread was calculated incorrectly.

I've tried to find this article:

1) "[3] Cox, D. C., "Delay Doppler characteristics of multipath propagation at 910 MHz in a suburban mobile radio environment," IEEE Transactions on Antennas and Propagation, Vol. AP-20, No. 5, pp. 625–635, Sept. 1972.";

2) "[1] ANSI J-STD-008, Personal Station-Base Station Compatibility Requirements for 1.8 to 2.0 GHz Code Division Multiple Access (CDMA) Personal Communications Systems, March 1995."

3) "[4] Pätzold, M., Mobile Fading Channels, Wiley, 2002.";

4) "[2] Bello, P. A., "Aeronautical channel characterizations," IEEE Trans. Commun., Vol. 21, pp. 548–563, May 1973.";

... (All from Matlab help), but -- unsuccessfully :(.