What is Fading ???
• Fading: rapid fluctuations of received signal strength
over short time intervals and/or travel distances.
• The fading phenomena results as a result of
constructive interference or Destructive interference
at the receiver side.
• Caused by interference from multiple copies of Tx
signal arriving @ Rx at slightly different times
How Fading Occur ????
• Fading signals occur due to reflections from ground & surrounding
buildings (clutter) as well as scattered signals from trees, people,
towers, in a Large Area.
Types Of Fading :
There two Main Types of Fading
1) Small Scale fading
2) Large Scale Fading
The Topic which I will Discuss here is the large Scale
Large Scale Fading is also Called Shadow Fading.
Large Scale Fading:
• Large Scale Fading occurs when an obstacle gets positioned between
the wireless device and the signal transmitter. This interference
causes significant reduction in signal strength because the wave is
shadowed or blocked by the obstacle.
• In the Diagram It is Clearly Given That there is an obstacle
between the Transmitter(Base station) and the
receiver(Mobile Station) Due to which a great variation occur
in the strength of the received signal.
2)The measured signal power differ substantially at different
locations even though at the same radial distance from a
3)Represents the medium scale fluctuations of the radio signal
strength over distances from tens to hundreds of meters
• Every Electromagnetic signal has its means average power
now when the phenomena of large scale fading occur then
this value deviates from the mean average value.
Large Scale Fading is Different from small Scale
• Small scale fading is concern with rapid fluctuation of
received signal strength over very short distance and
short time where as,
• Large scale fading concern with large fluctuation.