Large Scale Fading Prepared By Waqar Ahmad

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 Fading.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.

•Detail… • 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 transmitter.

3)Represents the medium scale fluctuations of the radio signal strength over distances from tens to hundreds of meters

Detail • 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 Fading:

• 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.

THANKS….