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Cognitive Radio: Next Generation Communication System

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Title: Cognitive Radio: Emerging Trend of Next Generation Communication System Author: INTEL Last modified by: Student Created Date: 2/9/2012 1:57:25 AM – PowerPoint PPT presentation

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Title: Cognitive Radio: Next Generation Communication System


1
Cognitive Radio NextGeneration Communication
System
  • By
  • V.ALAGU ABINAYA
  • 11MCO02

2
Evolution of Communication Systems
3
Software Defined Radio
  • Software Defined Radio as a basic platform on
    which to build a Cognitive Radio
  • Cognitive Radio can provide the spectral
    awareness technology to support FCC initiatives
    in Spectral Use

4
Definition of SDR
  • Software defined radios -evolutionary process
    from purely hardware-based equipment to fully
    software-based equipment.
  • 1. Hardware driven radios- Transmit
    frequencies, modulation type and other radio
    frequency (RF) parameters are determined by
    hardware and cannot be changed without
    hardware changes.
  • 2. Digital radios -A digital radio performs
    part of the signal processing or transmission
    digitally, but is not programmable in the field
  • 3. Software Defined Radios- All functions, modes
    and applications can be configured and
    reconfigured by software
  • SDR Forum-
  • - waveform properties, cryptography and
    applications, is re-programmable, and may be
    upgraded in the field with new capabilities
  • - Importance of Standards (APIs)

Notice of Proposed Rule Making (NPRM) 8/12/00
5
Cognitive Radio
6
Spectrum Allocation
7
COGNITIVE RADIO
  • Two-way radio
  • Automatically changes its transmission or
    reception parameters
  • communicates efficiently, avoiding interference
    with licensed or licensed exempt users.
  • Monitoring of several factors in the external and
    internal radio environment
  • -radio frequency spectrum, user behaviour and
    network state
  • FCC Federal Communication Commission
  • A software defined radio with a cognitive
    engine brain".

8
Cognitive Radio Means Smart and Alert
  • It knows where it is
  • It knows what services are
  • available, for example, it can identify then use
    empty spectrum to communicate more efficiently
  • It knows what services interest the user, and
    knows how to find them
  • It knows the current degree of needs and future
    likelihood of needs of its user
  • Learns and recognizes usage patterns from the
    user
  • Applies Model Based Reasoning about user needs,
    local content, environmental context

9
Need for Cognitive Radio
  • Radio spectrum is a scarce resource and is
    regulated
  • Spectrum usage is one of the key issues in
    communication system challenges
  • The spectrum efficiency can be improved with idea
    of dynamic spectrum allocation.
  • Cognitive radio network - on effective spectrum
    utilization
  • -allocates to primary user or licensed user
  • -user is not utilizing ,secondary user can
    claim without interfering
    to primary user

10
What is needed for a CR ?
11
Cognitive Radio Evolution
12
How Cognitive radio works?
  • Cognitive radio
  • -Spectrum sensing
  • -Spectrum management
  • -Spectrum mobility
  • -Spectrum sharing
  • awareness of changes in its environment
  • response to these changes adapts - operating
    characteristics
  • - improve its performance or to minimize
    a loss in performance

13
How Does a Cognitive Radio Get So Smart?
Mitola, Cognitive Radio for Flexible Mobile
Multimedia Communications, IEEE Mobile
Multimedia Conference, 1999, pp3-10
14
Spectrum Sensing
  • Dynamic spectrum allocation
  • Cognitive radio networks
  • scans the entire spectral band for the
    presence/absence of primary users
  • Performed either locally
  • - secondary user
  • - collectively by a group

Contd
15
Spectrum Sensing
Contd
  • Transmitter detection- capability to determine if
    a signal from a primary transmitter is locally
    present in a certain spectrum.
  • There are several approaches
  • -Matched filter detection
  • -Energy detection
  • -Cyclostationary feature detection
  • Cooperative detection- information from multiple
    Cognitive radio users are incorporated for
    primary user detection.
  • Interference based detection

16
Spectrum Management
  • Spectrum Management - capturing the best
    available spectrum to meet user communication
    requirements
  • Decide on the best spectrum band -Quality of
    service
  • These management functions can be classified
  • spectrum analysis
  • spectrum decision
  • Practical implementation of functions
  • - very complex and multifaceted issue in
    itself.

17
Spectrum Mobility
  • Spectrum Mobility- when a user exchanges its
    frequency of operation
  • - use the spectrum in a dynamic manner with the
    best available frequency band
  • - maintaining seamless communication
    requirements with better spectrum.

18
Spectrum Sharing
  • Spectrum Sharing provides the fair spectrum
    scheduling method
  • One of the major challenges is spectrum sharing.
  • It can be regarded to be similar to generic media
    access control MAC problems in existing systems

19
The future of CR
  • The unlicensed band in range of wireless devices
    and services
  • FCC - consider opening further bands for
    unlicensed use.
  • Exploits the inefficiently utilized licensed
    bands without causing interference to incumbent
    users
  • Unlicensed radios to operate in the TV broadcast
    bands and also TV services.

20
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21
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