Abstract:
The rapid advancement in the field of wireless communications that has
been expedited by the commercial demand for better services has led to the
application of wireless systems in many fields of life. Ranging from military
radio communication systems, to cellular systems and wireless sensor networks;
purposely emitted radio waves occupy major parts of the frequency spectrum.
The past few decades have seen the development of many wireless systems that
have been permanently allocated spectrum by regulatory authorities.
Direct and indirect observation of spectrum usage has identified the
temporal and spatial availability of spectrum within allocated frequency bands.
This implies that although spectrum scarcity is becoming a major problem,
however intelligent access to pre-allocated spectrum has the potential to enable
usage of licensed spectrum by unlicensed users on the pre-agreed condition of
minimum interference.
Cognitive networks promise to solve these problems of spectrum scarcity
by accommodating unlicensed (secondary) users in under-utilized segments of
the spectrum. Spectrum sensing forms the primary stimulus for a cognitive
radio and is vitally important for ensuring that the unlicensed users do not offer
intolerable levels of interference to licensed (primary) users. Cooperativespectrum sensing provides the capability to cognitive networks to overcome
problems related to “hidden” primary users. In this research, we have presented
a novel strategy that takes advantage of cooperative diversity to establish
grouping among cooperating secondary users. This strategy is then extended to
group-based spectrum sensing to establish a scheduling/ tasking mechanism.
The strategy ensures enhanced agility that will result in a reduction of
interference to primary users through their early detection
