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Implementation of OFDM Transmitter based on the IEEE 802.16d Standard. Presented by: Altamash Janjua, Umar Chohan Supervisors: Dr. Brian L. Evans and Mr. Ian Wong Technical TA: Mr. Youngok Kim Date: 2 nd December, 2004. Why is it Important to You?.
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Implementation of OFDM Transmitter based on the IEEE 802.16d Standard Presented by: Altamash Janjua, Umar Chohan Supervisors: Dr. Brian L. Evans and Mr. Ian Wong Technical TA: Mr. Youngok Kim Date: 2nd December, 2004
Why is it Important to You? • Tremendous Growth of Wireless Communications • Wireless Metropolitan Area Networks (WMANs) • Future Projects in the Industry www.gettyimages.com
Presentation Organization • Introduction • Transmitter Block Diagram • IEEE 802.16d Standards • Transmitter Implementation • Design Testing and Validation • Budget Constraints and Safety Features • Future Recommendations • Conclusion
x(t) t Signals and Modulation • Continuous-time and Discrete-time signals • Modulation : Carrier Amplitude and/or Frequency http://www.ece.utexas.edu/~bevans
What Is Orthogonal Frequency Division Multiplexing (OFDM)? • Multi-carrier Amplitude modulationscheme • Each Carrier’s amplitude is modulated • Well-suited for Wireless Communication Amplitude Frequency www.iec.org/online/ tutorials/ofdm/topic04.html
How OFDM works? Parallel Data Streams Data Encoding is based on Amplitude Modulation Multiple Carriers are combined through the Fourier Series Computed by Inverse Fast Fourier transform 4-QAM modulation
Channel Serial Data Source Serial To Parallel Encoding Bank IFFT Parallel To Serial Cyclic Prefix Our Simple Transmitter Block Diagram
Transmitter based on the IEEE 802.16d Standard • Upcoming Standard for Wireless Metropolitan Area Networks (WMANs) • Specifications Used • 256 FFT • 56 guard carriers • 16- QAM • Pilots and Guards
Transmitter Implementation • National Instruments Lab VIEW FPGA • VHDL and Lab VIEW programming • One Main Virtual Instrument (VI) • 16-QAM Encoding Bank • 256 point Complex IFFT core developed by Xilinx Inc. • Cyclic Prefix Module
Testing and Validation • Individual Modules Tested through Software Simulations • Developing a Host PC VI for the Testing of final Hardware • Sample test results provided in the IEEE 802.16d Standard
Safety Precautions • Fundamental Canon of Engineering: “Hold Paramount Public Health and Safety” • Repeated Design Testing for Functional Verification and Robustness • Additional Indicators for Warnings www.gettyimages.com
Budget Constraints • No Purchases Involved • Hardware and Software Provided by Supervisors • Time-Consuming • Currently testing the design www.gettyimages.com
Future Transmitter Implementations • Conventional Field Programmable Gate Arrays • Digital Signal Processors • Application Specific Integrated Circuits www.gettyimages.com
Acknowledgements • Supervisors: • Dr. Brian L. Evans • Mr. Ian Wong • Technical Teacher Assistant: • Mr. Youngok Kim
Conclusion Thank You!! Questions?? www.gettyimages.com