Cognitive radio is an enhancement of software defined radio that allows radios to sense their environment and change operating parameters accordingly. It was first proposed in 1998 as a way to more efficiently utilize limited radio frequency spectrum. A cognitive radio can sense available portions of spectrum, then dynamically use those available channels while avoiding occupied ones. This allows for greater spectrum utilization and more flexible interoperability between different wireless technologies. However, cognitive radio also faces significant hardware and software challenges around dynamic reconfiguration, interference avoidance, and security that must be addressed for it to be fully realized.

1. Cognitive Radio

2. Presented By :
 Mai Ahmed
 Asmaa Youssef
 Mohamed Hagazy
 Taqwaa Mahmoud
Cognitive Radio

3. contents
 History and introduction.
 Functions of Cognitive Radio.
 Architecture of Cognitive Radio.
 Applications.
 Challenges.

5.  Cognitive Radio is an enhancement of Software Defined radio
(SDR).
 SDR is the result of an evolutionary process from purely
hardware-based equipment to fully software-based equipment.
 The concept of cognitive radio was first proposed by Joseph
Mitola III in a seminar at KTH (the Royal Institute of Technology
in Stockholm) in 1998.
 The concept of cognitive radio published in an article by Mitola
and Gerald Q. Maguire, Jr. in 1999.

6.  Cognitive Radio is defines as a radio or system that senses
and is aware of its operational environment and can
dynamically and autonomously adjust its radio operating
parameter accordingly.
 Types of Radio
1. Fixed Radio : set by operators.
2. Adaptive radio: adjust itself to some sort of expected event and it
can changed mode of operation saved in its software but cannot
learn from experience.
3. Cognitive Radio: can sense their environment and learn how to
adapt.

7.  Cognitive radio learns from experience.
 Cognitive Radio deals with situations that are not planned at
the initial time of designed
 Types of Cognitive Radio:
1. Full cognitive radio: takes into account all parameters that a
wireless node or network can be aware of.
2. Spectrum-sensing cognitive radio: is used to detect
channels in the radio frequency spectrum.

8. Two main problems the Cognitive
radio solves
1. Spectrum Utilization
The proliferation of wireless devices and rapid growth of wireless
services continue to strain the limited spectral resource.

9. Two main problems the Cognitive
radio solves
1. Spectrum Utilization (cont)
“The only way t solve people’s need to communicate
wirelessly is by new technology .you cannot create
new spectrum” Dr.Martin Cooper, Past President of
Motorola and inventor of cell phone.

10. Two main problems the Cognitive
radio solves
1. Spectrum Utilization (cont)
 The Federal Communications Commission (FCC) ruled in
November 2008 that unused portions of the RF spectrum
(known as white spaces) be made available for public use.
 CR can access unused frequencies to extract more wireless
band.
 CR can uses frequencies and find available bandwidth where
other radios can only see static.
 CR represents technology solution to increase spectrum
capacity and utilization.

11. Two main problems the Cognitive
radio solves
1. Spectrum Utilization (cont)
 CR can access unused frequencies to extract more wireless
band.
 CR can uses frequencies and find available bandwidth where
other radios can only see static.
 CR represents technology solution to increase spectrum
capacity and utilization.

12. Two main problems the Cognitive
radio solves
2. Interoperability:
 Make communication between different technologies easily.
 Better Spectral efficiency.
 Flexible radio functionalities.
 Self organizing.

13. Functions of Cognitive Radio

14. Functions of Cognitive Radio.
Cognitive cycle

15. Functions of Cognitive Radio.
Main Functions
 Spectrum sensing.
 Spectrum management.
 Spectrum mobility.
 Spectrum sharing

16. Functions of Cognitive Radio.
Spectrum Sensing
 In order to avoid interference the spectrum
holes need to be sensed.
 Spectrum sensing techniques are divided
into three categories
 Non-cooperative detection.
 Cooperative detection.
 Interference based detection.

17. Functions of Cognitive Radio.
Spectrum Sensing
 Non-cooperative Detection
 cognitive radio acts on its own. The cognitive radio will
configure itself according to the signals it can detect
and the information with which it is pre -loaded.
 Cooperative Detection
 Group or network of CR share the sense information
they gain. central station will receive reports of signals
from a variety of radios in the network and adjust the
overall cognitive radio network to suit.

18. Spectrum Management
 Needed to capture the best available spectrum
to meet the best available spectrum to meet
user communication requirements.
 Cognitive radios should decide on the best
spectrum to meet the QoS requirements over
all available spectrum band.
 Management functions classified as:
 Spectrum Analysis
 Spectrum Decision
Functions of Cognitive Radio.

19. Spectrum Mobility
 The process where a cognitive radio user exchanges its
frequency of operation.
 The target is to use the spectrum in a dynamic manner
by allowing the radio terminals to operate in the best
available frequency band.
 Try to ensure that the data transmission by the
unlicensed user can continue in the new spectrum band
Functions of Cognitive Radio.

20. Functions of Cognitive Radio.
Spectrum Sharing
 Providing the fair spectrum scheduling
method
 Sharing is a major challenge in open
spectrum usage

21. Architecture of Cognitive Radio

22. Architecture of Cognitive Radio
Cognitive Radio Networks Architecture
The basic components of CRNs are the mobile station
(MS), base station/access point (BSs/APs) and
backbone/core networks. These three basic
components compose three kinds of network
architectures in CRNs:
1- Network architectures
2- Links in CRN
3- IP Mobility Management in CRN

23. Architecture of Cognitive Radio
1- Network architectures
A- Infrastructure-Based
B- Ad-hoc Architecture
C- Mesh Architecture

24. Architecture of Cognitive Radio
1- Infrastructure-Based
In the Infrastructure architecture, a MS can only access a BS/AP in the one-
hop manner. MSs under the transmission range of the same BS/AP shall
communicate with each other through the BS/AP. Communications between
different cells are routed through backbone/core networks. The BS/ AP may be
able to run one or multiple communication standards/protocols to fulfil
different demands from MSs. A cognitive radio terminal can also access
various kinds of communication systems through their BS/AP.
Infrastructure architecture of a CRN

25. Architecture of Cognitive Radio
2- Ad-hoc Architecture
There is no infrastructure support in ad-hoc architecture.
The network is set up on the fly. If a MS recognizes that there are some other MSs
nearby and they are connectable through certain communication
standards/protocols, they can set up a link and thus form an ad-hoc network. Note
that these links between nodes may be set up by different communication
technologies. In addition, two cognitive radio terminals can either communicate with
each other by using existing communication protocols (e.g., WiFi, Bluetooth) or
dynamically using spectrum holes .
Ad-hoc architecture of a CRN

26. Architecture of Cognitive Radio
3- Mesh Architecture
This architecture is a combination of the infrastructure and ad-hoc architectures plus
enabling the wireless connections between the BSs/APs .
This network architecture is similar to the Hybrid Wireless Mesh Networks.
the BSs/APs work as wireless routers and form wireless backbones.
MSs can either access the BSs/APs directly or use other MSs as multi-hop relay nodes.
Some BSs/APs may connect to the wired backbone/core networks and function as gateways.
. If the BSs/APs have cognitive radio capabilities, they may use spectrum holes to
communicate with each other
Mesh architecture of a CRN

27. Architecture of Cognitive Radio
2- Links in CRN

28. 3- IP Mobility Management in CRN
Architecture of Cognitive Radio

29. Applications

30. Applications
•Exploding Number of Heterogeneous
Networks
•Prolific use of wireless means new
challenges and opportunities for medical
care.
Patient monitor networks
•Body sensor network
•Low rate and low power
Wireless Health Care Environments

31. Applications
Smart Medicine container and wireless event
detection/notification system

32. Applications
ISM Wireless Network
• WLAN , Zigbee
,Bluetooth

• Medium rate and
power
• 2.4 GHZ and 5
GHZ
• Stationary
equipement

33. Applications
Low cost backhaul

34. Applications
Agriculture
 Irriwise “wireless radio crop monitoring
system”
 Provide data to help make better
decision on when and how long to
irrigate
 Lateral line water flow data confirm
zone runtime and volume
 Assists in precision control of irrigation
saving water and fertillzer
 Higher crop yields mean greater profits

35. Applications
Augmented Reality
 Sitelens a mobile augmented reality
system for urban design and urban
planning site visites
 Sitelens creates “situated
visualization”that are related to and
displayed in their environment
 Eg.representation of geocoded oxygen
concentration data are overlaid at the
site at which the data was recorded.

36. Applications
New Traffic Models
 Augmented Reality View
 True View

37. Challenges

38. Challenges
Lots of Challenges

39. Challenges
Software Challenges
 Run time reconfiguration needed
reprogramming of hardware in real
time .
Dynamic software architecture .
 Validation of software and general testing
 Structured and common APIS(Application
programming interface )
 security

40. Challenges
Hardware Challenges
Problems of SDR
 Very high performance RF and ADCs
High dynamic range
- Interference unpredictable
- Mitigate hidden nodes
Wide bandWidth
- Need to find available spectrum
- Need to determine contingent spectrum
- Antenna performance
Antennas
-Wide bandwidth
-Adaptable
High performance computing and memory
-Optimization requirements
- Low latency

41. Reference
• Cognitive Radio: Technology Survey and Future Research Directions By : José Marinho , CISUC, University of
Coimbra ISEC, Polytechnic Institute of Coimbra , Coimbra, Portugal Edmundo Monteiro , CISUC, University
of Coimbra ,Coimbra, Portugal