By: MUHAMMAD FARRUKH YAQUB
DEPARTMENT OF ELECTRICAL ENGINEERING.,
UNIVERSITY OF ENGINEERING AND TECHNOLOGY,
IEEE 802.22 Standard
Primary Vs Secondary Network
Cognitive Radio (As an example)
Conclusions and Further Work
Fixed Spectrum Policy.
The limited availability
and inefficient usage
creates the room to use
the wireless spectrum
NeXt Generation (xG)
Networks, Dynamic Spectrum
Access (DSA) and cognitive
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
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.
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
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.
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:
Processing at the
LNA ADC Software level
Related Characteristics of CR
Cognitive capability: Cognitive
capability refers to the ability of the
radio technology to capture or sense
the information from its radio
Spectrum sensing: A cognitive radio
monitors the available spectrum bands,
captures their information, and then
detects the spectrum holes .
Spectrum analysis: The
characteristics of the spectrum holes
that are detected through spectrum
sensing are estimated.
Spectrum decision: A cognitive radio
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.