BeamForming

Beamforming,which is playing a key role in modern era for evaluation of 5G technology.

It's also know as spatial filtering used in sensor arrays for directional signal transmission or reception.This can be achieved by combining the elements in an antenna array in such way that signals have to taken from particular angles. 

Beamforming can be used in both transmission end or reception end.

Lets take one example fig(1).for clear understanding of what beamforming & how it helps

When a navigator under water needs to send a signal from certain distance from hydrophone to ship,Then if he sends the signal directly to receiver in straight direction ,it will not reach them.He has to maintain some angle of elevation.

Phase alignment

  

In the above example,When arriving from -45° the signal reaches the left hand microphone first, when arriving from perpendicular to the array (called broadside) the signal reaches each microphone at the same time and when from +45° the right hand microphone receives the signal first.

So while sending the signal without delay one need to take care of  position of sensors in a room otherwise the sensor which is close to receiver need to send the signal first & then middle and at last from the final sensor.It results the accumulation of all the signals & receiver will get maximum gain in the output.This time delay in the narrow band systems  is called "PHASE SHIFT"

To ignore  the noise or jammers in the particular direction at the receiver beam former,The signal from each antenna may be  amplified at different weights.

There are two different types of Beam-forming techniques

1. Conventional Beamforming
2. Adaptive Beamforming.

In conventional,it uses fixed set of weightings & time delay to combine signals from sensor ,where as in adaptive combine the information with properties of signals to improve rejection of unwanted signals from other directions.

ex: These type of methods are used in the cocktail party programs.If one needs to extract the sound sensors in a room from different multiple speakers in different directions,Then it plays key role to identify & extract particular signals.


References :

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