Picocells provide coverage and capacity in areas difficult or expensive to reach using the more traditional macrocell approach.
[1] In cellular wireless networks, such as GSM, the picocell base station[2] is typically a low-cost, small (typically the size of a ream of A4 paper), reasonably simple unit that connects to a base station controller (BSC).
Multiple picocell 'heads' connect to each BSC: the BSC performs radio resource management and hand-over functions, and aggregates data to be passed to the mobile switching centre (MSC) or the gateway GPRS support node (GGSN).
[3] More recent work has developed the concept towards a head unit containing not only a picocell, but also many of the functions of the BSC and some of the MSC.
In particular, the integration of picocells with macrocells through a heterogeneous network can be useful in seamless hand-offs and increased mobile data capacity.