1. Implementation of OFDM Transmitter based on the IEEE 802.16d Standard Presented by: Altamash Janjua Group Partner: Umar Chohan Supervisors: Dr. Brian L. Evans and Mr. Ian Wong Date: September 23 rd, 2004

2. Why should you listen? Tremendous Growth of Wireless Communications Wireless Metropolitan Area Networks (WMANs) www.gettyimages.com

3. Presentation Organization Introduction What is Orthogonal Frequency Division Multiplexing? IEEE 802.16d Wireless Communications Standards Project Flow Diagram Transmitter Block Diagram Design Options and Trade-offs Conclusion

4. Introduction Continuous-time and Discrete-time signals Modulation : Carrier Amplitude and Frequency t x(t)x(t) http://www.ece.utexas.edu/~bevans/talks/UTSpecialEvents/SophEngHonors2003http://www.ece.utexas.edu/~bevans/talks/UTSpecialEvents/SophEngHonors2003.ppt

5. What is OFDM? Orthogonal Frequency Division Multiplexing Multi-carrier modulation scheme – Each Carrier’s amplitude is modulated www.iec.org/online/ tutorials/ofdm/topic04.html Amplitude Frequency

6. IEEE 802.16d Standard Upcoming Standard for Wireless Metropolitan Area Networks (WMANs) Specifications – Unlicensed bands below 11 GHz – 256 length IFFT – 56 guard carriers not used to carry data – Amplitude Modulation on each sub carrier to carry 1, 2, 4 or 6 bits www.linksys.com/products/ images/wp_802.asp

7. Project Flow Diagram

8. Simplified Transmitter Block Diagram Serial to Parallel Conversion Amplitude Modulation Mapping Bank 256-Length Inverse Fast Fourier Tranform Parallel to Serial Conversion Cyclic Prefix Parallel Data Streams Data Encoding is based on Amplitude Modulation Multiple Carriers are combined through the Fourier Series - Computed by Inverse Fast Fourier transform Serial Data In

9. Design Options and Trade-offs Transmitter – Design 1: LabVIEW floating-point desktop simulation – Design 2: LabVIEW fixed-point FPGA realization Design Trade-Offs – Bit error vs. Signal to Noise ratio – Implementation Complexity

10. Final Setup Transmitter: Implemented on the LabVIEW FPGA Channel: LabVIEW floating-point desktop simulation Receiver: LabVIEW floating-point desktop simulation

11. Conclusion Thank You! Questions?