In research area focus has recently been divided into basic studies, and more innovative studies.
In basic studies, typical research areas as network topology, indoor planning, capacity enhancements
like RF Repeaters, Self Organizing networks are studied. In basic research, one of the key targets
is to find a capacity solution / topology to get maximum increase and functionality for mobile networks.
This overall research problem can be specified to ask which type of layer i.e. macro, micro
(including small cells and outdoor DAS), mini (including femto/pico) cells are able to offer
"main capacity and functionality layer" for high capacity urban areas.
The following figure shows the division of research areas into to two main categories: