110 likes | 227 Views
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 . Why should you listen?. Tremendous Growth of Wireless Communications
E N D
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 23rd, 2004
Why should you listen? • Tremendous Growth of Wireless Communications • Wireless Metropolitan Area Networks (WMANs) www.gettyimages.com
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
x(t) t Introduction • Continuous-time and Discrete-time signals • Modulation : Carrier Amplitude and Frequency http://www.ece.utexas.edu/~bevans/talks/UTSpecialEvents/SophEngHonors2003.ppt
What is OFDM? • Orthogonal Frequency Division Multiplexing • Multi-carrier modulation scheme • Each Carrier’s amplitude is modulated Amplitude Frequency www.iec.org/online/ tutorials/ofdm/topic04.html
IEEE 802.16d Standard • Upcoming Standard forWireless 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
Simplified Transmitter Block Diagram 256-LengthInverse FastFourierTranform Serial Data In Serial to Parallel Conversion AmplitudeModulationMapping Bank Parallel to SerialConversion 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
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
Final Setup • Transmitter: Implemented on the LabVIEW FPGA • Channel: LabVIEW floating-point desktop simulation • Receiver: LabVIEW floating-point desktop simulation
Conclusion Thank You! Questions?