Date Added: Jul 2011
This paper presents an analytical model to approximate the probability distribution function of the aggregate interference that a primary user receives from multiple secondary transmitters. In particular, the authors consider heterogeneity in spatial distribution of secondary users such that there are several sites with densely populated secondary users in the whole area. The concentration of secondary users is modeled as an annulus sector with higher user density, which is termed hot zone. The mathematical framework presented in this paper can readily be adapted to various existing interference models.