Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 

What is multipath distortion?

Core Issue

There are frequent disconnection in associations because of multipath scattering or multipath distortion

Resolution

Generally as the RF signal starts travelling away from the transmitter they grow wider. When this expanding signal encounters an obstacle on its way , it is reflected , refracted etc. This reflection creates multiple wave fronts which takes mulitple path towards the receiver. This feature is called multipath. These waves experiences more delay than the main signal.

Genrally signal quality is reduced because of multipath behaviour. When the reflected signal arrive out of phase it adds to the signal strength of main signal. When they arrive in phase it adds to the signal strength of the main signal.

Workaround:

  • One way  to reduce the effect of multipath  scattering is to use diversity(Dual) antennas. Idea behind diversity is : beacause antennas are physically sepearated, even  if signals received on one antenna is worst, there is a probability that other antenna is reinforced by the inphase reflected signals . Most access points nowadays come with Dual antennas. Even if deployed manually , make sure antennas are only 5 inches apart.

  • Remove the obstacles if possible thereby reducing the possiblity of  Mulitpath. Generally Wireless Lans deployed in open environments which are free of obstacles they are not affected by Multipath.

For more  information on multipath scattering and diversity, refer to the Multipath section of Multipath and Diversity.

Problem Type

The signal is weak or fluctuating

Intermittent connectivity - flapping

Interference issues ( EMI / RF issues)

Products

Access point