  Secure spectrum auctions can revolutionize the spectrum utilization of
cellular networks and satisfy the ever increasing demand for resources. In this
paper, a multi-tier dynamic spectrum sharing system is studied for efficient
sharing of spectrum with commercial wireless system providers (WSPs), with an
emphasis on federal spectrum sharing. The proposed spectrum sharing system
optimizes usage of spectrum resources, manages intra-WSP and inter-WSP
interference and provides essential level of security, privacy, and obfuscation
to enable the most efficient and reliable usage of the shared spectrum. It
features an intermediate spectrum auctioneer responsible for allocating
resources to commercial WSPs by running secure spectrum auctions. The proposed
secure spectrum auction, MTSSA, leverages Paillier cryptosystem to avoid
possible fraud and bid-rigging. Numerical simulations are provided to compare
the performance of MTSSA, in the considered spectrum sharing system, with other
spectrum auction mechanisms for realistic cellular systems.
