802.22-Cognitive-Radio

Overview:

The devices for cognitive radio simulations in NetSim are CR BaseStation, Incumbent (PrimaryUser), CR_CPE (SecondaryUser) and Point to Multipoint (P2MP) links. CR Base Stations do cognitive sensing: the CPEs (SUs) sense the spectrum and send periodic reports of what they sense to the BS. The BS uses this information to detect Primary User (PU) activity. When the BS detects PU activity, the SUs pause their transmissions or change their transmit and receive channels.

The NetSim 802.22 PHY model adjusts the bandwidth, modulation and coding schemes dynamically. The MAC model uses Superframes, each made of many frames, with medium access through OFDMA. The NetSim 802.22 library gives 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
    • 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]

Cognitive Radio Networks

Cognitive Radio 2

Interface Cognitive Radio

Interface Cognitive Radio
Interface Cognitive Radio

Output Performance Metrics:

NetSim reports these network performance metrics:

  • Network Metrics
  • CR Base Station Metrics
  • CR CPE Metrics
  • CR Incumbent Metrics
  • CR Channel Metrics
  • IP metrics, TCP / UDP Metrics
  • Application Metrics
  • Dynamic metrics (graphical plot of an attribute over time) are available for application throughputs and individual link throughput also.

Additional Information:


Cognitive Radio Documentation (see the User Manual and Cognitive radio library)
Knowledgebase Q&A
File Exchange Link