  The growing demand in indoor small cell networks has given rise to the
concept of micro-operators (MOs) for local service delivery. We model and
analyze a spectrum sharing system involving such MOs where a buyer MO buys
multiple licensed subbands provided by the regulator. Also, all small cell base
stations (SBSs) owned by a buyer MO can utilize multiple licensed subbands at
the same time which are also used by other MOs. A deterministic model in which
the location of the SBSs are known can lead to unwieldy problem formulation,
when the number of SBSs is large. Subsequently, we adopt a stochastic geometric
model of the SBS deployment instead of a deterministic model. Assuming that the
locations of the SBSs can be modeled as a homogeneous Poisson point process, we
find the downlink signal-to-interference-plus-noise ratio (SINR) coverage
probability and average data rate for a typical user (UE) served by the buyer
MO in a spectrum sharing environment. In order to satisfy the QoS constraint,
we provide a greedy algorithm to find how many licensed subbands and which
subband for the buyer MO to purchase from the regulator. We also derive the
coverage probability of the buyer MO for interference the limited system.
