  With the rise of cheap small-cells in wireless cellular networks, there are
new opportunities for third party providers to service local regions via
sharing arrangements with traditional operators. In fact, such arrangements are
highly desirable for large facilities---such as stadiums, universities, and
mines---as they already need to cover property costs, and often have fibre
backhaul and efficient power infrastructure. In this paper, we propose a new
network sharing arrangement between large facilities and traditional operators.
Our facility network sharing arrangement consists of two aspects: leasing of
core network access and spectrum from traditional operators; and service
agreements with users. Importantly, our incorporation of a user service
agreement into the arrangement means that resource allocation must account for
financial as well as physical resource constraints. This introduces a new
non-trivial dimension into wireless network resource allocation, which requires
a new evaluation framework---the data rate is no longer the only main
performance metric. Moreover, despite clear economic incentives to adopt
network sharing for facilities, a business case is lacking. As such, we develop
a general socio-technical evaluation framework based on ruin-theory, where the
key metric for the sharing arrangement is the probability that the facility has
less than zero revenue surplus. We then use our framework to evaluate our
facility network sharing arrangement, which offers guidance for leasing and
service agreement negotiations, as well as design of the wireless network
architecture, taking into account network revenue streams.
