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MINTO
2010-06-29, 12:40 AM
Hi. i Have seen many vendors are using only log normal (slow) fade margin...not fast fade margin in link budget in wimax...i think its not correct..does anybody like to comment whether to use Fast Fade margin or not.

rapdoc
2010-06-29, 02:56 AM
Hi
i think you have reason ,we must use fast fading you can use 3 dB for the link budjet

firstmaxim
2010-06-29, 03:16 AM
Slow fading margin is a compensation for the environmental attenuation. It is going to be a function of the design value of coverage probability. The more coverage probability one requires, higher will be the slow fading margin, which in turn will improve service availability, but also increase network cost.

We dont have the luxury to compensate for fast fading, because the dynamic range for fast fading can be in excess of 30 dB (imagine a 30 dB compensation in the link budget!). So, we will resort to other techniques to handle fast fading, such as AMC, diversity or FPC or a combination of these.

Regards.