I. Introduction
Cell size reduction provides increased spectral reuse and increased data rates to mobile users. As the cell size decreases, the number of users per base station (BS) decreases leading to a greater bandwidth (or time share) per user. Cell size reduction can be achieved by increasing the density of the base stations, either by increasing the number of macro base stations or adding tiers of low powered base stations. There are two advantages of cell size reduction. Firstly, increased bandwidth per user. Secondly, lower transmit power since the mobile user is much closer to a base station.