  We propose a hybrid spectrum and information market for a database-assisted
TV white space network, where the geo-location database serves as both a
spectrum market platform and an information market platform. We study the
inter- actions among the database operator, the spectrum licensee, and
unlicensed users systematically, using a three-layer hierarchical model. In
Layer I, the database and the licensee negotiate the commission fee that the
licensee pays for using the spectrum market platform. In Layer II, the database
and the licensee compete for selling information or channels to unlicensed
users. In Layer III, unlicensed users determine whether they should buy the
exclusive usage right of licensed channels from the licensee, or the
information regarding unlicensed channels from the database. Analyzing such a
three-layer model is challenging due to the co-existence of both positive and
negative network externalities in the information market. We characterize how
the network externalities affect the equilibrium behaviours of all parties
involved. Our numerical results show that the proposed hybrid market can
improve the network profit up to 87%, compared with a pure information market.
Meanwhile, the achieved network profit is very close to the coordinated
benchmark solution (the gap is less than 4% in our simulation).
