  We study a cooperation model where the positions of base stations follow a
Poisson point process distribution and where Voronoi cells define the planar
areas associated with them. For the service of each user, either one or two
base stations are involved. If two, these cooperate by exchange of user data
and reduced channel information (channel phase, second neighbour interference)
with conferencing over some backhaul link. The total user transmission power is
split between them and a common message is encoded, which is coherently
transmitted by the stations. The decision for a user to choose service with or
without cooperation is directed by a family of geometric policies. The
suggested policies further control the shape of coverage contours in favor of
cell-edge areas. Analytic expressions based on stochastic geometry are derived
for the coverage probability in the network. Their numerical evaluation shows
benefits from cooperation, which are enhanced when Dirty Paper Coding is
applied to eliminate the second neighbour interference.
