JPL's Wireless Communication Reference Website Slide Show

Coherence Bandwidth

When do we experience frequency selective fading?

When is frequency diversity effective?

 

 

Definition of Coherence Bandwidth:

Coh. BW is the frequency separation for which the correlation coefficient is down from 1 to 0.5

Insert: 1 = 4p(f1 - f2) TRMS,

So Coh BW = 1 (4p TRMS)

We derived this for an exponential delay profile

 

 

Another rule of the thumb

ISI occurs if Tb > 0.1TRMS

 

 

Conclusion: keep transmission BW much less than Coh BW

 

 




JPL's Wireless Communication Reference Website Jean-Paul M.G. Linnartz, 1993, 1995.