  Within the framework of 5G, blockage effects occurring in the mmWave band are
critical. Previous works describe the effects of blockages in isolated and
multiple links for simple blocking objects, modeled with mathematical tools
such as stochastic geometry and random shape theory. Our study uses these tools
to characterize a scenario with $N$ links, including the possible correlation
among them in terms of blocking for several models of blocking objects. We
include numerical evaluations highlighting that assuming independence among the
links' blocking elements is a too-brief simplification and does not accurately
describe the real scenario. This paper also applies the formulation developed
for the case of $N$ links to optimize the relay positioning in mmWave cells for
coverage enhancement, that is, to minimize the communication failure
probability. We also show that both link budget and blockages affect the
optimum positioning of the relays as they are both essential for successful
transmission.
