This brief investigates spectrum efficient and energy efficient
strategies, known as cognitive radio networks (CRNs), to ensure secure
cooperation between licensed and unlicensed users. The authors address
issues of spectrum scarcity, spectrum sensing, transmission performance,
trust-aware cooperation, and secure communications. Two security-aware
cooperation based spectrum access schemes are presented. The first is a
trust-aware cooperative framework for CRNs to improve the throughput or
energy efficiency of licensed users and offer transmission opportunities
to unlicensed users, taking into consideration the trustworthiness of
unlicensed users. The second scheme is a cooperative framework to
enhance secure communications of licensed users. An introduction to CRNs
and literature survey enhance the discussion while numerical results are
provided to demonstrate the viability of the proposed schemes. The brief
is designed for researchers and professionals working with cognitive
radio networks or interested in cooperation based access. Advanced-level
students studying computer communication networks and communications
engineering will also find this brief useful.