March 2004 doc IEEE 802 15 04163 r

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March 2004 doc. : IEEE 802. 15 -04/163 r 0 Project: IEEE P 802.

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Harmonizing-TG 3 a-PHY-Proposals-for-CSM] Date Submitted: [18 March 2004] Source: [Matt Welborn] Company [Motorola] Address [8133 Leesburg Pike Vienna, VA USA] Voice: [703 -269 -3000], E-Mail: [mwelborn@xtremespectrum. com] Re: [] Abstract: [A proposal for a common frequency plan for DS-UWB and MB-OFDM to enable a common signaling mode] Purpose: [Provide technical information to the TG 3 a voters regarding a possible common signaling mode compromise] 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 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Outline • Goals of

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Outline • Goals of harmonizing – Enable interoperability – Maximize performance – Minimize complexity • Specific proposal – Frequency plan – FEC Submission 2 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Multiple Modes in a

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Multiple Modes in a Single PHY • A single PHY with multiple modes to provides a more complete solution for TG 3 a • A base mode that is required in all devices, used for control signaling & data traffic (CSM) – Beacons and control signaling – 9. 2 Mbps data rate, higher rates possible • Higher rate modes also required to support 110 & 200+ Mbps: – Compliant device can implement either DS-UWB or MBOFDM for higher rate modes • Provides a wider range of technical options for UWB applications Submission 3 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Frequency Plan for Data

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Frequency Plan for Data Modes • Common frequency plan for all modes – Based on common, cheap 26 MHz cell phone crystal – Minimal impact to existing MB-OFDM & DS-UWB proposals • MB-OFDM: use 572 MHz band spacing – 572 MHz = 22 x 26 MHz – Three bands between 3. 1 & 4. 8 GHz – 12 bands total (4 band groupings) • DS-UWB: use 4 different chip rates offset by 13 MHz each • CSM center frequency is 3978 MHz – Same as band #2 center for both MB-OFDM and DS-UWB – CSM chip rate is 3978 / 9 = 442 MHz Submission 4 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 What Does CSM Look

March 2004 doc. : IEEE 802. 15 -04/163 r 0 What Does CSM Look Like? One of the MB-OFDM bands! Proposed Common Signaling Mode Band (500+ MHz bandwidth) 9 -cycles per BPSK “chip” DS-UWB Low Band Pulse Shape (RRC) 3 -cycles per BPSK “chip” 3978 3100 Submission 4900 MB-OFDM (3 -band) Theoretical Spectrum 5 Frequency (MHz) Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Processing Rates for Data

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Processing Rates for Data Modes • DS-UWB uses 1326 MHz chip rate = 1/3 of 3978 MHz • MB-OFDM uses 572 MHz band center spacing – Increase of ~8% over original 528 MHz centers • ADC, DAC, FFT 8% faster clock speed • Removes need to transmit guard tones, still > 500 MHz BW • Increases transmit power by 0. 34 d. B – 12 bands total (4 groupings of 3 bands) • Center frequencies: 3406+572(n+1) MHz, n=1: 12 – Three bands between 3. 1 & 4. 9 GHz – One grouping still overlaps UNII – Places center of band #2 at 3978 MHz (will be used for CSM) Submission 6 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Analysis of Two FEC

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Analysis of Two FEC Options • CSM & both PHY modes need a common code – k=7 or k=6 convolutional code? • k=6 decoder is half the complexity of k=7 decoder – Viterbi decoder is a significant portion of the baseband complexity • What is the performance difference? – Gain is important at low rate and when punctured to high rates – Gain is important in AWGN, but more so in fading channel – K=7 code has more gain in AWGN – how much? – Multipath performance depends on code & diversity • MB-OFDM combines FEC with tone diversity at 110 Mbps – Which is better: 1/3 FEC with 2 x diversity or ½ FEC with 3 x diversity? Submission 7 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Code Performance in AWGN

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Code Performance in AWGN BER 10 -1 10 -2 10 -3 10 -4 10 -5 10 -6 10 -7 10 -8 10 -9 2 BER Performance of k=7 & k=6 codes BPSK R=11/32 R=5/8 R=3/4 K 6, R=1/2 Eb/No (d. B) 3 4 5 6 7 8 9 10 • K=7 code is 0. 6 d. B better than k=6 code in AWGN • K=7 code punctured to rate ¾ gives 4. 3 d. B gain Submission 8 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Diversity Improves Code Performance

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Diversity Improves Code Performance Comparison of K=7 code with 2 x diversity and k=6 code with 3 x diversity 10 -3 2 X+K 7 3 X+K 6 AWGN+K 7 10 -4 2 x diversity using 11/32 k=7 code in faded channel 0. 7 d. B 10 -5 BER 10 -6 -7 K=7 rate 10 11/32 code in AWGN 10 -8 4 3 x diversity using rate ½ k=6 code in faded channel 4. 5 5 5. 5 6 6. 5 Eb/No (d. B) • K=6 code with 3 x diversity gives 0. 7 d. B better code performance in fading environment than k=7 with 2 x Submission 9 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Conclusion of FEC Analysis

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Conclusion of FEC Analysis • For 110 Mbps mode in multipath, it is better to use more diversity and less FEC – Rate ½ k=6 code with 3 x diversity improves performance by 0. 7 d. B in multipath – Rate ½ k=6 decoder is half the complexity • Over 1 d. B better performance at 110 Mbps – Includes 0. 34 d. B increased transmit power • Lower complexity & power consumption – Reduction in Viterbi complexity more than compensates for increased bandwidth – Benefits both DS-UWB and MB-OFDM modes Submission 10 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Increased Symbol Rate •

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Increased Symbol Rate • If we increase the bandwidth, the MB-OFDM symbol length is shorter: ~224 ns • Increase symbol rate to 3. 3 MHz – – – 3. 3 MHz * 200 bits/symbol = 660 Mbps raw bit rate 110 Mbps mode: 3 x tone diversity with rate ½ FEC 205 Mbps mode: 2 x tone diversity with r=5/8 code 495 Mbps mode: 1 x tone diversity with r=¾ code Other optional modes still available • Increased symbol rate and shorter symbol still result in longer cyclic prefix – 70 ns cyclic prefix plus 10 ns guard time Submission 11 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Overview of CSM Signal

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Overview of CSM Signal • Uses 3978 MHz center frequency – Same as band 2 for both MB-OFDM and DS-UWB • Uses 442 MHz “chip rate” for spread BPSK modulation • Uses length 24 ternary spreading code – Unique codes for each piconet channel – Symbol interval is 55 ns – ISI will be negligible • Uses rate ½ k=6 convolutional code – Code is common to CSM, DS-UWB and MB-OFDM • Data rate is 9. 2 Mbps – 442 MHz / 24 * (1/2 code) = 9. 2 MHz – Higher rate possible with a shorter spreading code (e. g. L=12) Submission 12 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Link Budget for CSM

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Link Budget for CSM Submission 13 Welborn Motorola

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Conclusions • A plan

March 2004 doc. : IEEE 802. 15 -04/163 r 0 Conclusions • A plan to harmonize the two existing PHY proposals – Common frequency plan – Band #2 for CSM – Common FEC mode – also shared with CSM • Reduced complexity for DS-UWB and MB-OFDM implementations – Lower complexity than baseline MB-OFDM receiver • Increased performance in multipath • Enables a shared band for common signaling • A single PHY with multiple modes – CSM, DS-UWB and MB-OFDM Submission 14 Welborn Motorola