Gayaz Cognitive Radio Ppt

8/6/2019 Gayaz Cognitive Radio Ppt

1/13


2/13

A cognitive radio is a radio whose control processes permit the radio to

leverage situational knowledge and intelligent processing to

autonomously adapt towards some goal.

Cognitive radio is a paradigm for wireless communication in which either

a network or a wireless node changes its transmission or receptionparameters to communicate efficiently avoiding interference with

licensed or unlicensed users. This alteration of parameters is based on the

active monitoring of several factors in the external and internal radio

environment, such as radio frequency spectrum, user behaviour and

network state.


3/13

Cognitive radio(CR) is an emerging concept in wireless access,

aimed at improving the way radio spectrum is utilized. It signifies a radio that employs model based reasoning to achieve a

specified level of competence in radio related domains.


4/13

Estimation of interferencetemperature of the radioenvironmentDetection of spectrumholes

Estimation of channel-stateinformationPrediction of channelcapacity for use by thetransmitter


5/13


6/13

It was thought of as an ideal goal towards which a Software Defined

Radio platform should evolve: a fully reconfigurable wireless Black Box

that automatically changes its communication variables in response to

network and user demands.

Regulatory bodies in various countries (including the Federal

Communications Commission in the United States, and Ofcom in the

United Kingdom) found that most of the radio frequency spectrum was

inefficiently utilized For example, cellular network bands are overloadedin most parts of the world and concluded that spectrum utilization

depends strongly on time and place. Moreover, fixed spectrum allocation

prevents rarely used frequencies (those assigned to specific services)

from being used by unlicensed users, even when their transmissions

would not interfere at all with the assigned service. This was the reason

for allowing unlicensed users to utilize licensed bands whenever it would

not cause any interference (by avoiding them whenever legitimate user

presence is sensed). This paradigm for wireless communication is known

as Cognitive radio.


7/13

The first phone call over a cognitive radio network was made on Monday

11 January 2010 in Centre for Wireless Communications at University of

OULU using CWC's cognitive radio network CRAMNET(Cognitive

Radio Assisted Mobile Ad Hoc Network), that has been developed solelyby CWC researchers.


8/13

Main functions1. Spectrum sensing

Detecting unused spectrum

2. Spectrum management

Capturing the best available spectrum3. Spectrum mobility

Maintaining seamless communication duringthe spectrum transition

4. Spectrum sharing

Providing fair spectrum scheduling method


9/13

Improving spectrum utilization & efficiency

Improving link reliability

Less expensive radios

Advanced network topologies

Enhancing SDR techniques

Automated radio resource management.


10/13


11/13


12/13

y Improved link performancey Adapt away from bad channels

y Increase data rate on good channels

y Improved spectrum utilization

y Fill in unused spectrumy Move away from over occupied spectrum

y New business propositions

y High speed internet in rural areas

yHigh data rate application networks (e.g., Video-conferencing)

y Significant interest from FCC, DoD

y Possible use in TV band refarming


13/13

Documents

Gayaz Cognitive Radio Ppt