Implementation of ofdm

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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 Signals and Modulation x(t)   Continuous-time and Discrete-time signals t Modulation : Carrier Amplitude and/or Frequency http://www.ece.utexas.edu/~bevans What Is Orthogonal Frequency Division Multiplexing (OFDM)?  Multi-carrier Amplitude modulation scheme – 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 Our Simple Transmitter Block Diagram Serial Data Source Serial To Parallel Encoding Bank IFFT Parallel To Serial Cyclic Prefix Channel 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
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