  Fragmentation of expensive resources, e.g., spectrum for wireless services,
between providers can introduce inefficiencies in resource utilisation and
worsen overall system performance. In such cases, resource pooling between
independent service providers can be used to improve performance. However, for
providers to agree to pool their resources, the arrangement has to be mutually
beneficial. The traditional notion of resource pooling, which implies complete
sharing, need not have this property. For example, under full pooling, one of
the providers may be worse off and hence have no incentive to participate. In
this paper, we propose partial resource sharing models as a generalization of
full pooling, which can be configured to be beneficial to all participants.
  We formally define and analyze two partial sharing models between two service
providers, each of which is an Erlang-B loss system with the blocking
probabilities as the performance measure. We show that there always exist
partial sharing configurations that are beneficial to both providers,
irrespective of the load and the number of circuits of each of the providers. A
key result is that the Pareto frontier has at least one of the providers
sharing all its resources with the other. Furthermore, full pooling may not lie
inside this Pareto set. The choice of the sharing configurations within the
Pareto set is formalized based on bargaining theory. Finally, large system
approximations of the blocking probabilities in the quality-efficiency-driven
regime are presented.
