Microcell Research Paper

1.4.2 Microcell A microcell is a cell in a mobile phone network served by a low power cellular base station (tower), covering a limited area such as a mall, a hotel, or a transportation hub.A microcell uses power control to limit the radius of its coverage area. Typically the range of a microcell is less than two kilometres wide, whereas standard base-stations may have ranges of up to 35 kilometres (22 mi). A picocell, on the other hand, is 200 meters or less, and a femtocell is on the order of 10 meters, although AT&T calls its femtocell that has a range of 40 feet (12 m), a "microcell". AT&T uses "AT&T 3G MicroCell" as a trade mark and not necessarily the "microcell" technology, however.[3]
Microcells are often deployed temporarily during

They are mostly installed in the areas where there is insufficient macro penetration like buildings. They have same access features and dedicated backhaul as that in macro-cells.
1.4.4 Femtocells
It consist of low power user deployed access points with transmit power of less than 23 dBm and covering less than 50 m. They are also known as home BSs, which serve dozen of customers in home or enterprise buildings [48]. They overload data traffic by leveraging the user's existing broadband connections such as digital subscriber line, cable or optical fibre which is connected to cellular operator's network. Femto BSs work in open or closed subscriber group (CSG) access mode. It is speculated that they result in 70 % reductions in total annual cost as compared to macro only network deployment [49].
1.4.5 Relays They are access points generally deployed by the network operator and route data to the customers from the macro BS and vice-versa. They have similar transmit power levels as picocells and coverage area of 300 m. Relays are installed to increase signal strength and improve coverage in poor reception areas and dead zones like tunnels and cell edges. They can operate in transparent and non-transparent modes and require little or no incremental backhaul