January 2004 doc IEEE 802 15 04022 r

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Merger#2 Proposal Update ] Date Submitted: [12 January 2004] Source: [Reed Fisher(1), Ryuji Kohno(2), Hiroyo Ogawa(2), Honggang Zhang(2), Kenichi Takizawa(2)] Company [ (1) Oki Industry Co. , Inc. , (2)Communications Research Laboratory (CRL) & CRL-UWB Consortium ]Connector’s Address [(1)2415 E. Maddox Rd. , Buford, GA 30519, USA, (2)3 -4, Hikarino-oka, Yokosuka, 239 -0847, Japan] Voice: [(1)+1 -770 -271 -0529, (2)+81 -468 -47 -5101], FAX: [(2)+81 -468 -47 -5431], E-Mail: [(1)reedfisher@juno. com, (2)kohno@crl. go. jp, honggang@crl. go. jp, takizawa@crl. go. jp ] Source: [Michael Mc Laughlin] Company [deca. Wave, Ltd. ] Voice: [+353 -1 -295 -4937], FAX: [-], E-Mail: [michael@decawave. com] Source: [Matt Welborn] Company [Motorola, Inc. ] Address [8133 Leesburg Pike, Suite 700, Vienna, Va. 22182, USA] Voice: [+1 703. 269. 3000], FAX: [+1 703. 749. 0248], E-Mail: [mwelborn@xtremespectrum. com] Re: [Response to Call for Proposals, document 02/372 r 8, replaces doc 03/123] Abstract: [] Purpose: [Summary Presentation of the Merger #2 proposal. ] Notice: This document has been prepared to assist the IEEE P 802. 15. 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 802. 15. Submission 1 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 This Contribution is the Technical Update for Merger #2 Proposal • This document only contains supplemental information on the Merger #2 proposal. For additional details on the proposal, please see the latest version of the proposal document: 03/334 r 6 dated November 2003 Submission 2 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Major Contributors For This Proposal Update Matt Welborn Michael Mc Laughlin John Mc. Corkle Ryuji KOHNO Shinsuke HARA Shigenobu SASAKI Motorola Inc. deca. Wave Ltd. Motorola Inc. Yokohama National University Osaka University Niigata University Tetsuya YASUI Honggang ZHANG Kamya Y. YAZDANDOOST Kenichi TAKIZAWA Yuko RIKUTA CRL-UWB Consortium CRL-UWB Consortium Supported by: Motorola Members of CRL-UWB Consortium Submission 3 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Presentation Roadmap • Key differences between DS-UWB and MB-OFDM – Wide occupied bandwidth – Single carrier modulation • Transmit power calculations Submission 4 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Big Picture: What are the big differences between DS-UWB & MB-OFDM • Wideband DS-UWB – – Single band occupied by signal (versus frequency hopping) Compliant with existing regulations Superior multi-piconet performance Flexible transmit spectrum • Single carrier modulation – Excellent performance in indoor multipath channel • Low fade margins • Efficient architectures for energy capture – Scalable to very high data rates Submission 5 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Signal Occupies Fixed Bandwidth • Signal continuously occupies widest bandwidth & benefits from UWB advantages – Low fade margin (no Rayleigh fading) in multipath channels – Multipath resolution – Precision ranging • Other users appear as wideband uncorrelated noise – Offset chip rates for different piconets – Code sequences with low cross-correlation Submission 6 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Wide Band DS-UWB High Band Low Band 3 4 5 6 7 8 9 10 11 3 § Low Band (3. 1 to 5. 1 GHz) 4 5 6 7 8 9 10 11 § High Band (6. 2 to 10. 2 GHz) § 29 Mbps to 450 Mbps § 29 Mbps to 900 Mbps Multi-Band 3 Spectral Modes of Operation With an appropriate diplexer, the multi -band mode will support full-duplex operation (RX in one band while TX in the other) 3 4 5 6 7 8 9 10 11 § Multi-Band (3. 1 to 5. 1 GHz plus 6. 2 GHz to 10. 2 GHz) Submission 7 § Up to 1. 35 Mc. Gbps Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Compliant With Existing Regulations • In the initial rulemaking, the FCC & NTIA only studied signals that continuously occupied a single frequency band – Restrictions on gated signals only effective for such signals – MB-OFDM does not meet this criterion • APD interference analysis shows that MB-OFMD has identical interference properties to gated UWB signals that are specifically prohibited by the existing rules – Only allowed when power reduced according to duty cycle • An FCC rule change or interpretation to accommodate MBOFDM or other FH-UWB waveforms would be needed before certification by FCC • Deliberations in other regulatory bodies concerned about interference effects of hopped/gated UWB Submission 8 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 APD Analysis for DS-CDMA and MB-OFDMM Amplitude Probability Distribution in 50 MHz BW, 250 us Observation 20 AWGN DS - Root-Raised Cosine OFDM 3 OFDM 7 OFDM 13 15 15 10 d. B 10 5 5 0 0 -5 -5 -10. 001 0. 05 0. 1 0. 2 Probability of exceeding ordinate The gated OFDM signals have non. Gaussian APDs that indicate large amplitudes with higher probability than for DSUWB or AWGN Submission 11% Gated DS OFDM 7 11% Gated AWGN 9 0. 37 AWGN and noise-like DS-CDMA (Gaussian signals) have flat characteristic curves in an APD plot . 001 0. 05 0. 1 0. 2 Probability of exceeding ordinate The OFDM-7 signal has the same APD and interference properties as the prohibited gated-DS UWB signal The 11% Gated DS would be specifically prohibited by the UWB rules unless power is reduced by 9. 6 d. B Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Superior Multi-piconet Performance • DS-UWB uses FDM and CDM for multi-piconet support – Low band: 4 full-rate piconets – High band: 4 full-rate piconets (optional) – Both bands: 8 total full-rate piconets (optional) • Can provide total overlapped SOPs or full duplex operation • MB-OFDM uses frequency hopping for multi-piconet support – Mode 1: 4 full-rate piconets – Mode 2: 4 full-rate piconets (optional) • Require use of 3 lowest hop bands, so overlaps Mode I – Mode 1 + Mode 2: 4 full-rate piconets (optional) • Acquisition occurs in lower 3 bands • Mode 1 and Mode 2 devices operating together provide no additional SOP benefit (acquisition limited) Submission 10 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 DS-UWB Provides Spectral Flexibility • Signal continuously occupies single wide band – Data symbols are send serially over entire signal bandwidth • Receivers are designed to capture energy of transmit pulse through multipath channel – Many receive architectures affected only by difference in Tx power – Receiver performance not affected by Tx pulse shape/spectrum • As a result, transmit pulse can be modified without any coordination between transmitter and receiver – Flexibility to protect sensitive frequency bands or improve link performance – No resulting changes in data rate, interleaver, etc. – Requires no handshake or message protocol to establish or coordinate • Provides a path to global harmonization and compliance using optimized UWB pulses Submission 11 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 MB-OFDM Dynamic Bands and Tones Requires Dynamic Coordination • MB-OFDM proposes that “bands and tones can be dynamically turned on/off” for enhanced coexistence or to meet changing regulations – Dynamically dropping/adding tones or bands would require a message protocol to dynamically coordinate link parameter changes between transmitter and receiver: • Dynamic changes in bit-to-carrier tone mapping? • Changes to interleaver? Changes to hopping patterns/codes? • All would require dynamic coordination between transmitters and receivers – No details have been provided on this mechanism – Unknown impact on link and piconet performance • Loss of diversity protection against Rayleigh fading for affected bits? • Impact on link performance, data throughput, SOPs, or acquisition? – MB-OFDM bands with tones “turned off” may not meet the minimum 500 MHz bandwidth (at -10 d. B) that is required in the UWB rules • Prevents or limits “notches” in transmit spectrum Submission 12 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 DS-UWB: Excellent Performance in Indoor Multipath Channel • Low fade margins – Wide bandwidth results in low fading – For MB-OFDM, the combination of narrow carriers and punctured FEC degrades performance in multipath channels • 6 d. B or more degradation at 480 Mbps versus AWGN • Cannot be compensated for using equalization or other processing • Efficient architectures for energy capture – Rake and CMF architectures provide efficient and scalable energy capture • Equalization compensates for inter-symbol interference – Proven & widely used equalizer technology Submission 13 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 DS-UWB in Multipath • Indoor multipath channels provide several challenges for UWB systems – Multipath fading – Inter-symbol interference (ISI) – Energy capture • Effects are well-understood and are analyzed as trade-off between performance versus complexity • DS-UWB minimizes fading and provides scalable energy capture • MB-OFDM provides good energy capture at the expense of significant multipath fading Submission 14 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Compensating for ISI • ISI occurs as a result of non-uniform channel frequency response – Multipath delay spread exceeds the symbol interval • ISI is compensated for using an equalizer – Linear equalizer (digital filter) – Decision-feedback equalizer (DFE) • If left uncompensated, ISI can cause high BER & error floor phenomenon • Equalizer technology is widely used in many types of systems – Telephone modems – WLAN (e. g. 802. 11 b) – HDTV • OFDM systems use frequency domain equalization to compensate for phase and amplitude response of channel – If delay spread exceeds CP length, residual ISI compensation would require additional time-domain equalization Submission 15 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Example of ISI Effects on BER Uncoded Equalization Performance on CM 3 -15, 16 Finger Rake -1 No Equalization 9 -Tap Least-Squares DFE AWGN Channel Log 10 BER -2 -3 -4 -5 -6 5 10 Eb/No 15 20 • Un-equalized system experiences high BER and error floor • 9 -tap DFE with 16 -finger rake performance approaches AWGN Submission 16 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Equalizer Design Trade-offs • Equalizer is a key part of any modern wireless receiver architecture – Phase correction and MRC in an MB-OFDM receiver are equivalent to equalization in a DS-UWB receiver – without equalization, MB-OFDM receiver would fail to operate – 8 -bit channel estimate required for MB-OFDM • System design and simulation for DS-UWB without an equalizer results in sub-optimal performance – Degraded SNR due to uncompensated ISI – Presence of error floors due to uncompensated ISI – Poor narrow-band interference rejection and multi-piconet performance due to degraded SNR • • Complexity analysis involves many assumptions for a particular implementation – equalization is only one of them Complexity analysis without an equalizer results in excessive implementation complexity – Example: sub-optimal performance without an equalizer results in excessive bit-widths or rake taps and therefore unnecessary complexity – Small number of gates for equalizer may result in big complexity reduction Submission 17 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Eye diagram at Eb/No = 5 d. B Noise dominates ISI Submission 18 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Eye diagram at Eb/No = 10 d. B Noise/ISI at similar levels Submission 19 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Eye diagram at Eb/No = 15 d. B ISI dominates AWGN Submission 20 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Eye diagram at Eb/No = 20 d. B ISI dominates AWGN Submission 21 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Simulations without Equalizers Without Equalizer With Equalizer Uncompensated ISI leads to degraded SNR Equalizer improves output SNR longer range & lower BER Uncompensated ISI leads to “error floor” in simulation Equalizer removes error floor Uncompensated ISI leads to degraded NBI rejection from degraded SNR Equalizer improves NBI rejection performance Poor error performance without equalizer leads to excessive complexity estimates Improved performance allows lower complexity implementation Example: fewer bits needed for taps Example: Design for 4 -bit rake taps to 800 gate multiplier 400 gates achieve desired performance 204 K gate rake 102 K gate rake Submission 22 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Multipath Performance Conclusions • Energy capture and ISI compensation are SOLVED PROBLEMS for DS-UWB systems – Both are simple a complexity versus performance trade-off – Energy capture degradation is ~1 d. B (or less) for 16 -finger rake in CM 1 -3 and less CMF for modest complexity (regardless of data rate) – 64 -BOK modes outperform MB-OFDM without an equalizer, performance would improve with appropriate equalization • Performance scales with process technology – CMF, rake & equalizer require fewer gates and/or less power in faster & smaller process • Rayleigh fading for MB-OFDM cannot be mitigated by any amount of added signal processing – High rate modes degraded by 6 d. B or more relative to AWGN – Rayleigh fading performance does not improve with process technology or added digital processing Submission 23 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 PHY Comparisons • Previous example shows pitfalls of comparing proposals based only on simulations of a few specific implementations – Specific implementation decisions can lead to significant differences in performance and complexity estimates – Sub-optimal implementations lead to poor/irrelevant simulation results – Technology development and design optimization will lead to improved implementations • Best decision will also be based on fundamental or asymptotic performance bounds seasoned with experience and judgment – Leads to a standard that can continue to provide improved performance-to -cost as technology matures • DS-UWB provides scalable performance that exceeds MB-OFDM today and continues to improve with more sophisticated implementations – Scalable energy capture, ADC bit widths & equalizer performance – Scales to higher data rates without Rayleigh fading losses – Multi-user detection possible for improved SOP operation Submission 24 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Transmit Power Calculations • UWB average transmit power is constrained by FCC regulations based on power spectral density – Average power limit equivalent to -41. 25 d. Bm/MHz – Peaks in spectrum above “average” require reduction in transmit power to meet limit at highest power frequency • MB-OFDM proposed transmit power is -10. 3 d. Bm – -41. 25 d. Bm+10*Log(4. 125 MHz*300 data carriers) d. B = -10. 3 d. Bm – Assumes perfectly flat spectrum for each of the 300 QPSKmodulated carriers (100 data carriers each in 3 bands) at FCC limit – Used as basis for performance in all link budgets and simulations • All simulations to date appear to assume 0 d. B transmit power back-off • Any non-zero ripple in transmit spectrum would require reduction in transmit power – Would result in shorter ranges or worse BER performance Submission 25 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Realistic Measurement of Transmit Power • • Claim of perfectly flat MB-OFDM spectrum is based on theoretical result for zero-padded prefix OFDM over infinite signal duration Real limits will be based on spectrum analyzer measurements of transmit power during FCC certification testing – 1 MHz resolution bandwidth, RMS averaging, peak-hold • Real spectrum analyzer measurement with 1 MHz RBW and RMS averaging results in ripple for “theoretically flat” MB-OFDM signals – – 1 MHz RBW effectively integrates only about 1 microsecond of signal For MB-OFDM, this is little more than 1 symbol of data Carriers in each symbol are just sinusoids with “random” phases – not QPSK RMS averaging discards phase information so averaged carriers are not spread by multiple symbols of modulation with different phases – Instead, carriers begin to be “resolved” by 1 MHz RBW and RMS averaging • DS-UWB signal has > 1000 pulses in 1 micro-second observation – Spectrum in 1 MHz RBW is well-spread BPSK/QPSK with shape determined only by transmit pulse and MBOK code sequence Submission 26 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Realistic Measurement of Transmit Power • Calculations of MB-OFDM spectrum were made that show ~1 db of ripple in MB-OFDM power spectrum • Transmit power will need to be reduced by about 0. 5 d. B below the proposed level of -10. 3 d. Bm to compensate for spectral ripple MB-OFDM Signal Generation 1 MHz RBW Filter RMS Detector Plot of Power Spectrum Analysis • FCC testing based on current policy for gated UWB signals (equivalent to MB-OFDM interference characteristics) also requires power reduction based on signal duty cycle (e. g. 25% duty cycle 6 d. B attenuation) • No definitive interpretation has yet been issued by FCC WRT measurement procedures for frequency-hopped UWB Submission 27 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Radiated Emissions UWB Radio Sample 2 Test Distance: 1 m Detector: RMS RBW/VBW: 1 MHz/3 MHz Meas. Time: 1 ms Emissions: < Limit Apparent ripple of 6 d. B or more Note: Data normalized to 3 m test environment for limit comparison. *Plot from MBOA-reported spectrum measurements (assumed to have CP) Submission 28 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Calculated MB-OFDM Spectrum Normalized Power Spectrum (d. B) MB-OFDM Band 2 Signal Averaged over 1 ms Calculation Parameters Zero-padded Cyclic Prefix Detector: RMS RBW: 1 MHz Spectrum showing non-zero ripple Frequency (MHz) *Spectrum plot based on analysis using FCC measurement rules Submission 29 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Transmit Power Calculations • DS-UWB power based on RRC pulse shape + stated transmit power back-off to account for code sequence – -41. 25 d. Bm + 10*Log(1368 MHz) = -9. 9 d. Bm – 1368 MHz is 3 d. B bandwidth (RRC spectrum is symmetric about 3 d. B point on a linear scale) • Original transmit back-off numbers based on code sequence analysis (included 16 -BOK requirement) • Updated analysis results in lower back-off numbers: – – Submission 2 -BOK requires worst-case 1. 9 d. B back-off 4 -BOK requires worst-case 1. 2 d. B back-off 8 -BOK requires worst-case <1 d. B back-off 64 -BOK requires worst-case 0. 4 d. B back-off 30 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 MB-OFDM Power Assuming Favorable UWB Rules Change or Interpretation DS-UWB 4 -BOK DS-UWB 64 -BOK MB-OFDM Mode I -9. 9 d. Bm -10. 3 d. Bm 1. 2 d. B 0. 4 d. B 0. 5 d. B 0 d. B* Actual transmit power -11. 1 d. B -10. 3 d. B -10. 8 d. B Path loss 44. 4 d. B 44. 2 d. B -55. 5 d. Bm -54. 7 d. Bm -55. 0 d. Bm -0. 5 d. B +0. 3 d. B 0 d. B Theoretical transmit power Transmit back-off Attenuation for FCC compliance Received power WRT MB-OFDM *Assumes best-case favorable UWB rules change or interpretation to allow higher power frequency-hopped UWB despite gated-UWB interference characteristics Submission 31 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 MB-OFDM Power Assuming Limits Based on Gated-UWB Interference Characteristics DS-UWB 4 -BOK DS-UWB 64 -BOK MB-OFDM Mode I -9. 9 d. Bm -10. 3 d. Bm 1. 2 d. B 0. 4 d. B 0. 5 d. B 0 d. B -5. 9 d. B* Actual transmit power -11. 1 d. B -10. 3 d. B -16. 7 d. B Path loss 44. 4 d. B 44. 2 d. B -55. 5 d. Bm -54. 7 d. Bm -60. 9 d. Bm +5. 4 d. B +6. 2 d. B 0 d. B Theoretical transmit power Transmit back-off Attenuation for FCC compliance Received power WRT MB-OFDM *Assumes current FCC measurement procedure for frequency-hopped UWB based on gated-UWB power attenuation requirements (attenuation based on 26% duty cycle for Mode I – Mode II higher) Submission 32 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Consequences of Revised Transmit Back-off Results • DS-UWB transmit back-off analysis leads to higher transmit power – 0. 6 d. B higher for 64 -BOK 7% range increase (if noise limited) – 0. 9 d. B higher for 4 -BOK 11% range increase (if noise limited) • Calculated MB-OFDM spectral ripple leads to lower transmit power and decreased range – 0. 6 d. B lower Tx power 7% range reduction • Relative gain with Tx power back-off adjustments: – 4 -BOK vs. MB-OFDM: +1. 4 d. B – 64 -BOK vs. MB-OFDM: +1. 1 d. B • MB-OFDM power reduction to account for FCC compliance without favorable rules change/interpretation leads to 5. 9 d. B reduction – Total 6. 4 d. B power reduction 52% range reduction Submission 33 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium

January 2004 doc. : IEEE 802. 15 -04/022 r 0 Conclusions • Primary differences between DS-UWB and MB-OFDM – Use of a single continuously occupied band – Use of single carrier modulation • ISI compensation through equalization is well understood and widely used – Can lead to significant performance improvements for DS-UWB • PHY evaluation should also emphasize fundamental limitations – Example: limited scalability for MB-OFDM to higher data rates due to Rayleigh fading in multipath channels • Realistic transmit power calculations will lead to more reliable range and performance predictions Submission 34 Mc Laughlin, deca. Wave; Welborn, Motorola & Kohno, CRL-UWB Consortium