  Cooperation in cellular networks has been recently suggested as a promising
scheme to improve system performance. In this work, clusters are formed based
on the Mutually Nearest Neighbour relation, which defines which stations
cooperate in pair and which do not. When node positions follow a Poisson Point
Process (PPP) the performance of the original clustering model can be
approximated by another one, formed by the superposition of two PPPs (one for
the singles and one for the pairs) equipped with adequate marks. This allows to
derive exact expressions for the network coverage probability under two
user-cluster association rules. Numerical evaluation shows coverage gains from
different signal cooperation schemes that can reach up to 15% compared to the
standard non-cooperative network coverage. The analysis is general and can be
applied to any type of cooperation or coordination between pairs of
transmitting nodes.
