KUAR WiMAX 802.16a OFDM Jordan Guffey

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KUAR WiMAX 802.16a OFDMJordan Guffey
WiMAX
OFDM

• Worldwide Interoperability for Microwave Access
• Designed to provide Metropolitan Area Access.
  Provides for wireless networking access at
  distances up to 50 km, rather than hundreds of
  meters with WiFi. MAN ( Metropolitan Area
  Network) rather than LAN ( Local Area Network ).
• Used as last-mile connection for broadband
  access.
• Operates at 10-66 GHz licensed frequencies and
  2-11 GHz unlicensed frequencies.

• The WiMAX standard 802.16a (2-11 GHz) supports an
  OFDM (Orthogonal Frequency Division Multiplexing)
  physical layer. OFDM allows much higher data
  rates over non-line-of-sight connections.
• One high-rate data stream is broken up into many
  lower-rate data streams. Each stream is assigned
  to a OFDM sub-carrier. This scheme mitigates
  frequency selective fading, a major bottleneck to
  wireless communications.

• Frequency selective fading with a single carrier
  system must be corrected by equalization. At very
  high data rates, equalization can become
  prohibitively complicated.

OFDM Spectrum
KUAR Implementation

• Frequency domain view of a 4 carrier OFDM signal.
  Under ideal conditions, there is zero
  inter-carrier interference.

• Goal Implement an adjustable OFDM transceiver in
  the KUAR (KU Agile Radio) that complies with the
  802.16a OFDM PHY specifications.
• Challenges
• Fitting all the required logic in the Virtex II
  FPGA.
• Complex error control coding scheme.
• OFDM extremely sensitive to timing and frequency
  offsets.
• Strategy Implement the OFDM model in Simulink,
  then synthesize each block in VHDL. Each block
  will then be extensively tested in the FPGA with
  data generated from the Simulink model.