  The coordination of base stations in mobile access networks is an important
approach to reduce harmful interference and to deliver high data rates to the
users. Such coordination mechanisms, like Coordinated Multi-Point (CoMP) where
multiple BSs transmit data to a user equipment, can be easily implemented when
centralizing the data processing of the base stations, known as Cloud RAN.
  This centralization also imposes significant requirements on the backhaul
network for high capacities and low latencies for the connections to the base
stations. These requirements can be mitigated by (a) a flexible placement of
the base station data processing functionality and by (b) dynamically assigning
backhaul network resources. We show how these two techniques increase the
feasibility of base station coordination in dense mobile access networks by
using a heuristic algorithm.
  We furthermore present a prototype implementation of our approach based on
software defined networking (SDN) with OpenDaylight and Maxinet.
