Microcell

A cell having a very small coverage area, which could be as small as one floor of an office building, one part of an airline terminal, or one corner of a busy intersection. These cells are typically used when coverage and/or capacity is strained and the use of a normal sized cell would cause interference or would be impractical to install. These cells transmit with extremely low power outputs. (Cingular)

A very small cell used in densely populated areas where traffic volume is high. (There is no official definition of what cell radius distinguishes a small cell from a microcell.) (Motorola)