1. By: MUHAMMAD FARRUKH YAQUB
LECTURER
DEPARTMENT OF ELECTRICAL ENGINEERING.,
UNIVERSITY OF ENGINEERING AND TECHNOLOGY,
LAHORE

2. Layout
Back Ground

 IEEE 802.22 Standard
 Primary Vs Secondary Network
 Cognitive Radio (As an example)
 Spectrum Measurements
 Conclusions and Further Work

3. Background
Fixed Spectrum Policy.

The limited availability

and inefficient usage
creates the room to use
the wireless spectrum
opportunistically.
NeXt Generation (xG)

Networks, Dynamic Spectrum
Access (DSA) and cognitive
radio networks.

4. IEEE 802.22 WRAN
The IEEE 802.22 Working Group was formed in November 2004 with the task of

developing a standard for wireless regional area network (WRAN) based on cognitive
radio technology.
This project, called the standard for wireless regional area networks (WRAN), efficient

utilization of UHF/VHF TV bands between 54 and 862 MHz.
The operating principle is to make unlicensed access to

unused or under-utilized TV spectrum.

5. Features(IEEE 802.22)
Base-station coverage range 100 km if the

power is not an issue.
Sense the spectrum.

Identify unused TV Spectrum.

Utilize this Spectrum.

No harmful interference is caused to the

licensed users.

6. Primary Vs Secondary Network
Primary Network: An existing network infrastructure is generally
referred to as the primary network. For example TV broadcast networks. The
components of the primary network are primary user and primary base-station.
They have license of the spectrum so they don’t need to incorporate any extra
functionality to support secondary network.
Secondary Network: Secondary network (or cognitive radio network,
Dynamic Spectrum Access network, xG network, unlicensed network) does not
have license to operate in a desired band. Hence, the spectrum access is allowed
only in an opportunistic manner. The components of secondary spectrum are
secondary user and secondary base-station. They are unlicensed users and
have to incorporate extra functionality to efficient utilize the spectrum without
causing interference or degradation to the primary(licensed) network.

7. xG/Secondary Network Architecture

8. Cognitive Radio Technology
A ‘‘Cognitive Radio’’ is a radio that can

change its transmitter parameters
based on interaction with the
environment in which it operates.
Cognitive radio techniques provide the

capability to use or share the spectrum in
an opportunistic manner.
Cognitive Radio can be called as an

intelligent software defined radio(SDR).
The block diagram for SDR is given by:
ANTENNA
Processing at the
LNA ADC Software level

9. Related Characteristics of CR
Cognitive capability: Cognitive
1.
capability refers to the ability of the
radio technology to capture or sense
the information from its radio
environment.
Spectrum sensing: A cognitive radio
a.
monitors the available spectrum bands,
captures their information, and then
detects the spectrum holes .
Spectrum analysis: The
b.
characteristics of the spectrum holes
that are detected through spectrum
sensing are estimated.
Spectrum decision: A cognitive radio
c.
determines the data rate, the
transmission mode, and the bandwidth
of the transmission. Then, the
appropriate spectrum band is chosen
according to the spectrum
characteristics and user requirements.

10. Spectrum measurements
(120-200MHz)

11. Spectrum measurements
(200-300MHz)

12. Spectrum measurements
(300-600MHz)

13. Conclusions and Further work
Availability of the unused spectrum.

 Spatial and Temporal model to avoid
interference with the primary user.
 Dynamic Spectrum Sharing.
 Quality of Service.

14. Thank you very much.