Refer to the exhibit.

The signal transmitted from the AP is reflected off a wall resulting in
multipath interference at the client end. Which statement is true?

A.
The transmitted signal from the AP arrives at the client at slightly different times resulting
in phase shifting.

B.
If signal 2 is close to 360 degrees out of phase with signal 1, the result is essentially zero
signal or a dead spot in the WLAN.

C.
Multipath interference is less of an issue when using a DSSS technology because
multipath is frequency selective.

D.
If signal 1 is in phase with signal 2, the result is essentially zero signal or a dead spot in
the WLAN.

E.
Multipath interference is solved by using dual antennas.

Explanation:
In order to understand diversity using dual antenna’s, you must understand multipath
distortion. When a radio frequency (RF) signal is transmitted towards the receiver, the
general behavior of the RF signal is to grow wider as it is transmitted further. On its way, the
RF signal encounters objects that reflect, refract, diffract or interfere with the signal. When
an RF signal is reflected off an object, multiple wavefronts are created. As a result of these
new duplicate wavefronts, there are multiple wavefronts that reach the receiver.
Diversity is the use of two antennas for each radio, to increase the odds that you receive a
better signal on either of the antennas. The antennas used to provide a diversity solution can
be in the same physical housing or must be two separate but equal antennas in the same
location. Diversity provides relief to a wireless network in a multipath scenario. Diversity
antennas are physically separated from the radio and each other, to ensure that one
encounters less multipath propagation effects than the other. Dual antennas typically ensure
that if one antenna is in an RF null then the other is not, which provides better performance
in multipath environments. You can move the antenna to get it out of the null point and
provide a way to receive the signal correctly.
Reference:
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a008019f646.sh
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