CWS RF Behavior & Signal Propagation 2

Question 1

Which phenomenon causes a wireless signal to bend around corners or obstacles?

Accepted Answer

Diffraction

Answer

Diffraction allows RF signals to bend around the edges of obstacles, enabling coverage in areas not in direct line of sight.

Question 2

What is the Fresnel zone primarily used to evaluate in wireless deployments?

Accepted Answer

Path clearance for line-of-sight links

Answer

Fresnel zones define elliptical regions around a line-of-sight path where obstructions can cause signal degradation due to phase cancellation.

Question 3

Multipath propagation in an indoor environment most commonly results in which condition?

Accepted Answer

Signal fading and intersymbol interference

Answer

Multipath causes copies of the signal to arrive at different times, leading to fading and intersymbol interference that degrades throughput.

Question 4

In free-space path loss calculations, doubling the distance between transmitter and receiver increases path loss by approximately how many dB?

Accepted Answer

6 dB

Answer

Free-space path loss follows an inverse-square law, so doubling distance quadruples path loss, which is a 6 dB increase.

Question 5

Which 802.11 technique was specifically designed to mitigate multipath-induced intersymbol interference?

Accepted Answer

OFDM guard interval (cyclic prefix)

Answer

The OFDM cyclic prefix (guard interval) absorbs multipath delay spread, preventing symbols from overlapping at the receiver.

(CWS) Certified Wireless Specialist Practice Test