doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Pulsed-UWB-OFDM] Date Submitted: [14 July 2003] Source: [Ahmed H Tewfik] Company [University of Minnesota] Address [Dept. of Electrical and Computer Engineering, Room EECS Bldg.,Minneapolis, MN 55455] Voice:[ ], FAX: [ ], Re: [03147r0P802-15_TG3a-University-of-Minnesota-CFP-Presentation.ppt] Response to a Call for Contributions Task Group 3a Call For Intent and Proposals, November 2002, updated January 2003, 02371r0P802-15_SG3a-5_Criteria.doc Abstract:[We propose a multi-carrier UWB system for WPAN communications. We describe system design issues and proposed transmitter and receiver structures. We also provide a self-evaluation of the proposed system.] Purpose:[For consideration by a task group.] Notice:This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release:The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 2 Pulsed-UWB-OFDM A.H. Tewfik and E. Saberinia University of Minnesota

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 3 Overview Pulsed-UWB-OFDM Comparison with Pure-OFDM Proposed System Transmitter and Receiver Structures Coexistence and Multiple piconets Complexity and Power Consumption Conclusion

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 4 Basic Idea Using OFDM modulation to simplify channel equalization, capturing channel energy and digital modem implementation Using Pulsed-OFDM instead of normal OFDM to add the ability of getting the advantages of multi-path diversity and decreasing Complexity Dividing the whole bandwidth to multiple sub- bands and hopping between these bands in order to frequency spreading and multi- piconet support

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 5 What is Pulsed-OFDM? A Pulsed OFDM symbol is frequency spreading of OFDM signal using a shaping pulse that is wider than the bandwidth of OFDM signal This is equal to using a pulse with duty cycle less than 1 for sending every symbol out of OFDM modulation ( out of IFFT block)

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 6 Normal OFDM block in Time- Frequency symbol rate=1/Tu W=symbol rate N Tu t f(MHz) W 0

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 7 Pulsed OFDM block in Time-Frequency 0 T u T=4Tu T+T u (N-1)T (N-1)T+ Tu t f(MHz) W symbol rate=1/T W=1/Tu=symbol rate*(T/Tu) ( frequency spreading )

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 8 Multi-path diversity in Pulsed-OFDM In Pulsed OFDM we can resolve multipath for delays:  <  -Tu Lets Spreading gain is equal K=T/Tu be an integer Then we can resolve K multipath (get K independent virtual channel)

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 9 Simulation Results Simulation For CM4

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 10 Single-Channel To Multi-Channel A pulsed-UWB-OFDM over a channel with L tap Pure-OFDM over K independent channel with L/K tap K=T/Tr

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 11 Single-Channel To Multi-Channel Provides K multipath diversity Captures all the channel energy K=1 is pure OFDM K=channel length is Multi-band system

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 12 Spectrum Bandwidth=1.65GHz Multipath resolution=0.6ns Bandwidth=7.5GHz Multipath resolution=0.13ns

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 13 Proposed System N=32 Subcarrier C=8 Cyclic Prefix 2/3 Convolutional Channel Coding QPSK Constellation Ts=1.8 ns Duty Cycle K=4 for 110Mbits/s (4 multipath diversity) K=3 for 165Mbits/s (3 multipath diversity) K=2 for 220Mbits/s (2 multipath diversity) K=1 for 440Mbits/s

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 14 Transmitter DAC Convolutional Encoder Interleaver Constellation Mapping IFFT Insert Pilots Add CP & GI Frequency Hopping exp(j2  f c t) Input Data

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 15 Receiver BPF LNA sin(2  f c t) cos(2  f c t) Remove CP 4x 32-point FFT LPF VGA ADC One Tape equalizer and combine channels De interleaver Decoder De mapping

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 16 Transmitter Complexity 2/3 Convolution Coder IFFT 32-point QPSK only D/A operating at 130 to 520 MHz

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 17 Receiver Complexity Simple equalization and channel estimation using cyclic prefix and FFT: –4 x 32-Point QPSK FFT –128 1-tap equalizer decoder

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 18 Coexistence

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 19 Multiple Piconets Simultaneous operation achieved by proper selection of: –FH code –Use of pilots –Add pseudo-random codes on top of modulation –Combination

doc.: IEEE Submission July 14, 2003 Tewfik/Saberinia, U. of MNSlide 20 Conclusion Pulsed-UWB-OFDM used OFDM modulation in order to: –Avoids Rake type receiver with reasonable size FFT-IFFT –Simple channel equalization and synchronization –Capture the channel energy Pulsed OFDM use Pulsating normal OFDM in order to: –Frequency spreading –Providing multipath diversity –Decrease the complexity of the transceiver