Cognitive radio technology aims to tackle frequency shortage and misuse by allowing radios to detect unused spectrum and adapt transmission parameters. It was introduced by Mitola in 1999 to define radios that can evaluate their environment, decide transmission parameters, and learn from experience. The technology faces challenges in reliably sensing primary users, distinguishing them from noise, and developing commercial applications. If these challenges can be addressed, cognitive radio networks may offer a robust wireless connection between many intelligent devices regardless of location.

1. COGNITIVE RADIO TECHNOLOGY CHALLENGES
Nafel N. Alotaibi
PHD Candidate
University of Manchester
Feb 2014

2. Spectrum Frequency Shortage & misuse
Spectrum frequency and allocation

3. CR Technology
 In order to tackle the problem of frequency shortage
and misuse, the idea of cognitive radio (CR) is
considered.
 The principle of the CR was introduced by Mitola in
1999.
 The CR can be defined as the radio which equipped with
intelligent algorithms that help it and its network to
evaluate the environment around them, and decide the
best values to reconfigure the appropriate parameters
to transmit the desired data, in addition to learning
from the previous experience.

4. The architecture of CRNs
 The network architecture consists of two main categories;
licensed spectrum, and CRNs.
 The cognitive radio should monitor the licensed spectrum in
order to find the holes that are caused by the idle primary
user.
CRN architecture (Zhang et al., 2012)

5. CR functions
 Spectrum sensing: to give the CR enough information
about the environment around it.
 Spectrum management: the CR monitors the
spectrum and find out the opportunities to perform
the best quality of service.
 Spectrum mobility: involves policies and protocols
aimed to allowing dynamic frequency use and
frequency hopping.
 Spectrum sharing: the CR aims to serve as many
secondary users as it can, by providing fair spectrum
sharing strategies.

6. Challenges
The fundamental technical 'bottleneck' in the way of CR
development is reliable spectrum sensing:
 Sensing the primary user
 Distinguishing it from the white noise and other
secondary users.
 Find commercial applications to help CR technology to
flourish.
 Also, there is a need for using an accurate and realistic
propagation model.
 The ability to reconfigure its parameters in order to offer
the flexibility, to move from specific frequency to
another without loosing the service reliability.

7. Future of CR Technology
 A new era of telecommunication networks is expected.
There will be a huge wireless network which consists of a
massive number of smart nodes.
 The CR networks will offer a robust connection between all
radios in addition to intelligent devices such as sensors and
smart monitoring cameras (regardless of time and location).

8. Conclusion
 CR promises to solve the shortage and misuse of spectrum.
 A reliable spectrum sensing System is the main problem that
the research attempts to tackle.
 The expected effects of this technology on the future of
telecommunications field are amazing, because the efficiency
of the network will be improved dramatically, which means
more wireless services with higher speeds and wider storage
capacity as well as increasing the reliability and stability of the
wide area networks.