Performance of Directed Retry in Non-Uniform Cellular Environments

This paper investigates the effects of directed retry
(DR) in cellular networks characterized by a nonuniform environment,
that is, with unequal distribution of users and/or radio resources.
We propose an analytical model able to take both propagation
and network aspects into account. The nonuniform environment
is modeled assuming the superposition on a uniform scenario
of a circular area characterized by different offered load or radio
capacity. The case of a hot spot of users is included. Path loss and
lognormal shadowing have been considered. This is done through a
statistical approach which is very general, and provides an expression
for the probability of receiving a suitable power level from a
given number of base stations within a fixed distance from the mobile.
A comparison to simulation results is performed to validate
the model. We show that the impact of DR on the blocking probability
depends largely on the propagation parameters considered.