This paper presents a study on interference in microcellular networks with reuse patterns based on a square grid. The performance of the system is assessed by means of the carrier-to-interference (C/I) ratio for a series of situations such as: the worst case condition, mobiles randomly positioned, and channel activity according to a given traffic intensity. General formulas are presented for all possible reuse patterns, and graphical results are presented for systems with clusters of 5, 8, 9, 10 and 13 microcells. The results show an outstanding improvement in performance when compared to those for the worst case condition presented in previous works of the same authors.2 15941598