802.22-Cognitive-Radio

Overview:

Devices that are used for cognitive radio simulations in NetSim are CR BaseStation, Incumbent (PrimaryUser), CR_CPE (SecondaryUser) and Point to Multipoint (P2MP) links. CR Base Stations perform cognitive sensing, i.e the CPEs (SUs) sense the spectrum and send periodic reports to the BS informing it about what they sense. The BS, with the information gathered, detects Primary User (PU) activity. When PU activity is detected the transmissions of SU’s are paused or the SU’s change the transmitting and receiving channels.

NetSim 802.22 PHY model allows for dynamic adjustment of bandwidth, modulation and coding schemes. The MAC model consists of Superframes which is formed by many frames, with medium access via OFDMA. NetSim 802.22 library provides specialized output metrics such as Spectral efficiency, SCH sent / received, FCH sent / received, UCS sent, Primary User - Operational time, Idle time and interference time

CR covers the following protocols:

  • Application Layer
    • Different application protocols can be modelled here such as HTTP, CBR, Email, Video, Voice, FTP etc.
  • Transport Layer
    • TCP with different variants (like Old Tahoe, Tahoe, Reno, New Reno, BIC CUBIC)
    • UDP
  • Network Layer
    • IPv4
  • Data Link Layer
    • Protocol: IEEE802.22-2011
    • Duplexing: TDD (Time Division Duplexing)
    • Management Message configuration: By changing the value of DSX_Request and Response Retries parameters
    • Different time stamps: T7, T8, T14, T16, T29 and T31 waiting timers are available.
    • Channel Maintenance Parameters: Channel check time, NonOccupancyPeriod, Channel detection time, False alarm probability, Channel move time, Num sensing period, Sensing period, Sensing Interval, Candidate channel refresh time, Backup channel refresh time, Candidate channel time and Wait before channel moves are available
    • Sensing mode
  • Physical Layer
    • Protocol: IEEE802.22-2011
    • Minimum and Maximum frequency range is 54MHz to 862MHz
    • Channel Bandwidth – 6,7,8 MHz
    • Modulation Techniques – QPSK, 16QAM, 64QAM
    • Coding Rate – 1/2, 2/3, 3/4, 5/6
    • Back off start and Back off end range between 0 to 15
    • Transmitter Power – 1 to 5000 mW
    • Upstream Channel Change Wait Time: 2 sec
    • Transmit/Receive Transition Gap: 210 µs
    • DL_UL_Ratio – 1:1, 1:2, 1:3, 1:4
    • IFQP Cycle Length – 0 to 15
    • IFQP Cycle Length – 0 to 15
    • Data Rates
    • Min: 4.54 Mbps [Condition: QPSK modulation, Coding rate 1:2 and Spectral Efficiency 0.76]
    • Max: 22.69 Mbps [Condition: 64QAM modulation, Coding Rate 5:6 and Spectral Efficiency 3.78]

Network Scenario:
Output Performance Metrics: A variety of network performance is reported including
  • Network Matrics
  • CR Base Station Metrics
  • CR CPE Metrics
  • CR Incumbent Metrics
  • CR Channel Metrics
  • IP metrics, TCP / UDP Metrics etc
  • Application
  • Dynamic metrics (Graphical plot of an attribute over time) is available for application throughputs and individual link throughput also.
Additional Information:
Knowledgebase Q&A
File Exchange Link
Video Links One
Video Links Two