  In this paper, we study the impact of the base station (BS) idle mode
capability (IMC) on the network performance in dense small cell networks
(SCNs). Different from existing works, we consider a sophisticated path loss
model incorporating both line-of-sight (LoS) and non-line-of-sight (NLoS)
transmissions. Analytical results are obtained for the coverage probability and
the area spectral efficiency (ASE) performance for SCNs with IMCs at the BSs.
The upper bound, the lower bound and the approximate expression of the
activated BS density are also derived. The performance impact of the IMC is
shown to be significant. As the BS density surpasses the UE density, thus
creating a surplus of BSs, the coverage probability will continuously increase
toward one. For the practical regime of the BS density, the results derived
from our analysis are distinctively different from existing results, and thus
shed new light on the deployment and the operation of future dense SCNs.
