Digital Signal Processing Reference
In-Depth Information
Fig. 1.3
A comparison between the cognition cycles of Mitola and Haykin
1.4 Cognitive Radio: Exploiting Flexibility with Intelligent
Control
The Cognitive Radio (CR) concept brings an answer to exploit the increased flexi-
bility with smart(er) control solutions.
The CR was first described by Mitola in [15, 16] as a decision making layer
in which “
wireless personal digital assistants and the related networks were suffi-
ciently computationally intelligent about radio resources, and related computer-to-
computer communications, to detect user needs as a function of use context, and
to provide radio resources and wireless services most appropriate to those needs
”.
Through the eyes of Mitola CR was a natural extension of the SDR. His CR cycle
can be seen in Fig.
1.3
(a).
Six years after Mitola's first CR article, Simon Haykin recapitulated the CR
idea as an enabler of brain-empowered communication [17]. He identified six key
parts of CR: awareness, intelligence, learning, adaptivity, reliability and efficiency.
Thus, his definition broadly complies with Mitola's viewpoint. In his seminal paper,
Haykin instantiated CR for OSA as can be seen in Fig.
1.3
(b). In this simplified
cognition cycle only 2 key elements of his CR are instantiated: environment aware-
ness (radio-scene analysis and channel estimation) and adaptivity (transmit power
control and dynamic spectrum management).
Together with the initial focus of CR research on enabling environmental aware-
ness through spectrum sensing, this led to people using CR as an equivalent of OR.
