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Attenuation:

     Attenuation is defined as loss in quality of the signal.

    For eg: When a person calls you from a distance, you will hear their voice somewhat lower. In this case, signal lowers with respect to distance.

    

Types of Attenuation:

Reflection:

     Do you know why TV DTH antenna is placed outsite to receive signal?

     This is because TV DTH operates at high frequency.

  • Input frequency: 10.7 - 11.70 GHz / 11.7 - 12.75 GHz
  • Local Oszilatorfrequenz (LOF): 9.75 GHz / 10.6 GHz

Signal reflection from a buildingSignal reflection from a building

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

High frequency gets reflected on hitting the surface. This is why 4G signals won't penetrate as much as GSM/CDMA signal (because 2G GSM/CDMA has low frequency than that of 4G signal)

        Low frequency signals can easily penetrate easily. This is why FM radio signal can travel over long distance.

 

The signal you receive in your mobile phone/FM is the combination of direct wave and reflected waveThe signal you receive in your mobile phone/FM is the combination of direct wave and reflected wave

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Diffraction:

Let's consider the signal hits the obstacle (Building), some signal will be reflected, some will penetrate the obstacle and some gets diffracted.

See what happens when signal hits the building Ref: nurkarimah777.blogspot.comSee what happens when signal hits the building Ref: nurkarimah777.blogspot.com

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ref: nurkarimah777.blogspot.in/ BS: Base StationRef: nurkarimah777.blogspot.in/ BS: Base Station

 

 

 

 

 

 

 

 

 

 

 

 

Solution to overcome Attenuation:

 

Cisco has came up with a solution to overcome the problem of attenuation in trains.

 

It is difficult for the working people to do video conference or seamless browsing during train travel.

 

Attenuation in trainAttenuation in train

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 To overcome this problem, Cisco is developing "trackside network".

 

This will be implemented with 5G network.

 

Cisco UK and Ireland CEO Scott Gardner announced the upcoming trial of the world’s fastest train WiFi in Scotland.

 

Ref:

https://blogs.cisco.com/sp/why_wait_for_5g_for_rail_wifi