  Technologies which will lead to adaptive, intelligent, and aware wireless
communications systems are expected to offer solutions to the capacity,
interference, and reliability problems of wireless networks. The spectrum
sensing feature of cognitive radio (CR) systems is a step forward to better
recognize the problems and to achieve efficient spectrum allocation. On the
other hand, even though spectrum sensing can constitute a solid base to
accomplish the reconfigurability and awareness goals of next generation
networks, a new perspective is required to benefit from the whole dimensions of
the available electro (or spectrum) hyperspace, beyond frequency and time.
Therefore, spectrum sensing should evolve to a more general and comprehensive
awareness providing mechanism, not only as part of CR systems but also as a
communication environment awareness component of an adaptive spectrum
hyperspace access (ASHA) paradigm which can adapt sensing parameters
autonomously to ensure robust signal identification, parameter estimation, and
interference avoidance. Such an approach will lead to recognition of
communication opportunities in different dimensions of the spectrum hyperspace,
and provide necessary information about the air interfaces, access techniques
and waveforms that are deployed over the monitored spectrum to accomplish ASHA,
resource and interference management.
