Cellular Systems Cellular Concepts The cellular concept was a ...

EE5401 Cellular Mobile Communications
EE5401 Cellular Mobile Communications
Solution can be found using the graph provided. (n :
path loss exponent)
The mean signal level at any distance is determined
by path loss and the variance is determined by the
resulting fading distribution (log-normal shadowing,
Rayleigh fading, Nakagami-m, etc). In this course, we
will deal with log-normal shadowing only.
The proportion of locations covered at a given
distance (cell boundary, for example) from BS can be
found directly from the resultant signal pdf/cdf.
The proportion of locations covered within a circular
region defined by a radius R (the cell area, for
example) can be found by integrating the resultant
cdf over the cell area.
Example: if n=4, σ=8 dB, and if the boundary is to
have 75% coverage (75% of the time the signal is to
exceed the threshold at the boundary), then the
area coverage is equal to 94%.
If n=2, σ=8 dB, and if the boundary is to have 75%
coverage, then the area coverage is equal to 91%.
An operator needs to meet certain coverage criteria.
This is typically the “90% rule” – 90% of a given
geographical area must be covered for 90% of the
time.
Institute for Infocomm Research 61 National University of Singapore
Institute for Infocomm Research 62 National University of Singapore