COMPUTER NETWORKS AND COMMUNICATIONS
WIRELESS COMMUNICATION TECHNOLOGIES
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Small Scale or Fading Models
|
|
|
Large Scale or Path loss Models
|
|
|
Either A or B
|
|
|
None of the above
|
Detailed explanation-1: -l As the mobile moves away from the transmitter over. larger distances, the local average received signal will gradually decrease. This is called large-scale path loss.
Detailed explanation-2: -The large scale fading is used to describe the signal level at the receiver after traveling over a large area (hundreds of wavelengths). Small scale fading is used to describe the signal level at the receiver after encountering obstacles near (several wavelengths to fractions of wavelengths) the receiver.
Detailed explanation-3: -Path loss is a dilution of the transmitted energy as the radiated wavefront expands during its travel from transmitter antenna to receiver antenna. For example, when communicating from Earth to a geosynchronous satellite (at an altitude of 37, 786 km) at S-band (∼2 GHz, ≈ 0.15 m), the path loss term is−190 dB.
Detailed explanation-4: -Path loss may be due to many effects, such as free-space loss, refraction, diffraction, reflection, aperture-medium coupling loss, and absorption.