  Multibeam systems with hundreds of beams have been recently deployed in order
to provide higher capacities by employing fractional frequency reuse.
Furthermore, employing full frequency reuse and precoding over multiple beams
has shown great throughput potential in literature. However, feeding all this
data from a single gateway is not feasible based on the current frequency
allocations. In this context, we investigate a range of scenarios involving
beam clusters where each cluster is managed by a single gateway. More
specifically, the following cases are considered for handling intercluster
interference: a) conventional frequency colouring, b) joint processing within
cluster, c) partial CSI sharing among clusters, d) partial CSI and data sharing
among clusters. CSI sharing does not provide considerable performance gains
with respect to b) but combined with data sharing offers roughly a 40%
improvement over a) and a 15% over b).
