@unpublished{TUW-240905, author = {Taranetz, Martin and Heath, Robert W. and Rupp, Markus}, title = {Modeling Two-Tier Heterogeneous Cellular Networks in Dense Urban Environments}, year = {2015}, keywords = {Small Cells; Heterogeneous Cellular Network; Urban Topology; Building Density; Boolean Model; Stochastic Geometry; Virtual Building Approximation;}, note = {invited; talk: II Jornada en Tecnolog{\'\i}as Emergentes en Informaci{\'o}n y Comunicaciones, A Coru{\~n}a; 2015-09-25} }