WIRELESS COMMUNICATIONS
PHYSICAL PROBLEMS OF THE MEDIUM
The physical layer over wireless medium has a lot of problems due to the signal nature:
- shadowing
- frequency-selective fading
- rayleight fading
signal can also bounce over reflective surfaces generating reflections
There are also meteorological conditions that can influence the signal strength.
In real scenarios with mobile nodes, mathematical models cannot be used to estimates the power loss due to the nature of the environment been to variable.
In general it can be said that power fluctuations depends on the distance from the transmitter.
layer 2 protocols need to take into account this physical layer problems