As an alternative approach, a sensing can be considered. In
this case, the new cell senses the spectrum and discovers all
cells in its neighborhood. This method enables automatic
derivation of the NCL for new cells. In addition, the NCL is
adapted depending on changes in transmission characteristics
(e.g., transmitting power). The problem of sensing is in
determination of an appropriate threshold for adding a cell to
the NCL. As shown in [14], the threshold should be related to
the cell radius. Another weakness of sensing is so-called
hidden nodes problem [13][15]. This issue increases in
significance with deployment of cells with small radius, such
as femtocells or picocells. These cells can be deployed close to
each other, for example, along a road or a street, but they are
not able to sense each other due to walls between them and
their low transmission power. Proposals on how to minimize
hidden node problem are introduced, for example, in [13][15].