Doc.: IEEE 802.15-03/449r0 Submission November 2003 A. Dabak, TI, R. Aiello, Staccato, et al.Slide 1 Project: IEEE P802.15 Working Group for Wireless Personal

November 2003

A. Dabak, TI, R. Aiello, Staccato, et al.Slide 1

doc.: IEEE 802.15-03/449r0

Submission

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [Multi-band OFDM Physical Layer Proposal Update]Date Submitted: [10 November, 2003]Source: [Presenter 1: Roberto Aiello] Company [Staccato Communications] [Presenter 2: Anand Dabak] Company [Texas Instruments] [see page 2,3 for the complete list of company names, authors, and supporters]

Address [12500 TI Blvd, MS 8649, Dallas, TX 75243]Voice:[214-480-4389], FAX: [972-761-6966], E-Mail:[[email protected]]

Re: [This submission is in response to the IEEE P802.15 Alternate PHY Call for Proposal (doc. 02/372r8) that was issued on January 17, 2003.]

Abstract: [This document describes the Multi-band OFDM proposal for IEEE 802.15 TG3a.]

Purpose: [For discussion by IEEE 802.15 TG3a.]

Notice: This document has been prepared to assist the IEEE P802.15. 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 P802.15.

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Submission

This contribution is a technical update authored by*:

Texas Instrument [03/141]: BatraFemto Devices [03/101]: CheahFOCUS Enhancements [03/103]: BoehlkeGeneral Atomics [03/105]: AskarInstitute for Infocomm Research [03/107]: ChinIntel [03/109]: BrabenacMitsubishi Electric [03/111]: MolischPanasonic [03/121]: MoPhilips [03/125]: KerrySamsung Advanced Institute of Technology [03/135]: KwonSamsung Electronics [03/133]: ParkSONY [03/137]: FujitaStaccato Communications [03/099]: AielloST Microelectronics [03/139]: RobertsTime Domain / Alereon [03/143]: KellyUniversity of Minnesota [03/147]: TewfikWisair [03/151]: Shor

* For a complete list of authors, please see page 3.

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Submission

Authors from 17 affiliated companies/organizations

Femto Devices: J. CheahFOCUS Enhancements: K. Boehlke General Atomics: N. Askar, S. Lin, D. Furuno, D. Peters, G. Rogerson, M. WalkerInstitute for Infocomm Research: F. Chin, Madhukumar, X. Peng, SivanandIntel: J. Foerster, V. Somayazulu, S. Roy, E. Green, K. Tinsley, C. Brabenac, D. Leeper, M. HoMitsubishi Electric: A. F. Molisch, Y.-P. Nakache, P. Orlik, J. ZhangPanasonic: S. MoPhilips: C. Razzell, D. Birru, B. Redman-White, S. KerrySamsung Advanced Institute of Technology: D. H. Kwon, Y. S. KimSamsung Electronics: M. ParkSONY: E. Fujita, K. Watanabe, K. Tanaka, M. Suzuki, S. Saito, J. Iwasaki, B. HuangStaccato Communications: R. Aiello, T. Larsson, D. Meacham, L. Mucke, N. Kumar, J. Ellis ST Microelectronics: D. Hélal, P. Rouzet, R. Cattenoz, C. Cattaneo, L. Rouault, N. Rinaldi,, L.

Blazevic, C. Devaucelle, L. Smaïni, S. Chaillou Texas Instruments: A. Batra, J. Balakrishnan, A. Dabak, R. Gharpurey, J. Lin, P. Fontaine,

J.-M. Ho, S. Lee, M. Frechette, S. March, H. YamaguchiTime Domain / Alereon: J. Kelly, M. PendergrassUniversity of Minnesota: A. H. Tewfik, E. SaberiniaWisair: G. Shor, Y. Knobel, D. Yaish, S. Goldenberg, A. Krause, E. Wineberger, R. Zack, B.

Blumer, Z. Rubin, D. Meshulam, A. Freund

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Submission

In addition, the following 19 affiliated companies support this proposal:

Adamya Computing Technologies: S.ShettyBroadcom: J. Karaoguz

Fujitsu Microelectronics America, Inc: A. Agrawal Furaxa: E. GoldbergHewlett Packard: M. FidlerInfineon: Y. RashiJAALAA: A. AnandakumarMicrosoft: A. HassanNEC Electronics: T. Saito

Nokia: P. A. RantaRealtek Semiconductor Corp: T. ChouRFDomus: A. MantovaniSiWorks: R. BertschmannSVC Wireless: A. YangTDK: P. CarsonTRDA: M. TanahashitZero: O. UnsalUWB Wireless: R. Caiming QuiWisme: N. Y. Lee

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Submission

Why did 10 Companies Propose Multi-Band Solutions in March 2003 ?

Some of the reasons include:

Spectrum Flexibility / Agility Regulatory regimes may lack large contiguous spectrum allocations Spectrum agility may ease coexistence with existing services

Energy collected per RAKE finger scales with longer pulse widths used Fewer RAKE fingers

Reduced bandwidth after down-conversion mixer reduces power consumption and linearity requirements of receiver

Fully digital solution for the signal processing is more feasible than a single band solution for the same occupied bandwidth

Transmitter pulse shaping made easier Longer pulses easier to synthesize & less distorted by IC package & antenna properties

Have the ability to utilize an FDMA mode for severe near-far scenarios

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Most of the Multi-Band Proposals in March 03’ used Pulses, What Happened ?

Energy collection under severe multipath (CM3, CM4) required improvement

We needed a computationally efficient method of multipath combining Parallel receivers? Infinite RAKE? OFDM?

OFDM in each sub-band was selected as a successor to the pulsed multi-band approaches

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Why are 37+ Companies Now Supporting the Multi-band OFDM Approach ?

Multi-band OFDM kept the unique Multi-Band benefits and solved the energy collection problem very elegantly

Feasibility studies of FFT and Viterbi cores showed encouraging numbers for gate-count and power consumption

Multi-band OFDM suitable for CMOS implementation (all components) Antenna and pre-select filter are easier to design (can possibly use

off-the-shelf components) Low cost + low power + CMOS integrated solution = early market adoption Scalability:

Digital section complexity/power scales with improvements in technology nodes (Moore’s Law).

Analog section complexity/power scales slowly with technology node

Much more can be said in detail about the Multi-band OFDM PHY performance, but first we should review our proposal…

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Overview of OFDM OFDM was invented more than 40 years ago

Adopted by numerous standards effort: Asymmetric Digital Subscriber Line (ADSL) services. IEEE 802.11a/g; IEEE 802.16a Digital Audio Broadcast (DAB); Home Plug Digital Terrestrial Television Broadcast: DVD in Europe, ISDB in Japan

OFDM is also being considered for 4G, IEEE 802.11n and 802.20

OFDM is spectrally efficient. IFFT/FFT operation ensures that sub-carriers do not interfere with each other

OFDM has an inherent robustness against narrowband interference. Narrowband interference will affect at most a couple of tones. Information from the affected tones can be erased and recovered via the forward

error correction (FEC) codes OFDM has excellent robustness in multi-path environments.

Cyclic prefix preserves orthogonality between sub-carriers. Cyclic prefix allows the receiver to capture multi-path energy more efficiently

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Overview of Multi-Band OFDM Basic idea: divide spectrum into several 528 MHz bands

Information is transmitted using OFDM modulation on each band OFDM carriers are efficiently generated using an 128-point IFFT/FFT Internal precision is reduced by limiting the constellation size to QPSK

Information bits are interleaved across all bands to exploit frequency diversity and provide robustness against multi-path and interference

60.6 ns prefix provides robustness against multi-path even in the worst channel environments

9.5 ns guard interval provides sufficient time for switching between bands

Solution is very scalable and flexible Data rates, power scaling, frequency scaling, complexity scaling

*See latest version of 03/268 for more details about the Multi-Band OFDM system

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Band Plan

Group the 528 MHz bands into 4 distinct groups.

Group A: Intended for 1st generation devices (3.1 – 4.9 GHz). Group B: Reserved for future use (4.9 – 6.0 GHz). Group C: Intended for devices with improved SOP performance (6.0 – 8.1 GHz). Group D: Reserved for future use (8.1 – 10.6 GHz).

Use of Group A is mandatory, while use of Group A+C is optional.

f3432MHz

3960MHz

4488MHz

5016MHz

5808MHz

6336MHz

6864MHz

7392MHz

7920MHz

8448MHz

8976MHz

9504MHz

10032MHz

Band#1

Band#2

Band#3

Band#4

Band#5

Band#6

Band#7

Band#8

Band#9

Band#10

Band#11

Band#12

Band#13

GROUP A GROUP B GROUP C GROUP D

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FCC Compliance of Multi-band OFDM

Presenter: Anand Dabak

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Submission

Interference and the FCC (1)

In 03/153r9 (July 2003), XSI stated:“The issue today is NOT whether or not there is

more or less interference, the issue is, what are the rules”

XSI/Motorola filed a petition with the FCC for declaratory ruling immediately after the San Francisco meeting: Q: Should a multi-band OFDM waveform be transmitted at a lower power

than other UWB systems?

The FCC response (full response in back-up slides): FCC’s concern is not with interpretations of the rules, but rather with

interference. “We urge that IEEE perform technical analyses to ensure that any UWB

standard it develops will not cause levels of interference beyond that already anticipated by the rules.”

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Interference and the FCC (2)

Interference: We have identified several systems that need to be considered by any UWB

transmitter. Most of these systems are out of band (OOB) and require adoption of an appropriate

spectral mask to ensure appropriate level of protection. Several simulation studies completed looking at impact of MB-OFDM waveform on

various FEC schemes often employed in wideband FSS systems. Several (measurement based) experiments are being conducted to determine

impact to real systems.

MB-OFDM does not cause any more interference than already anticipated by current FCC rules.

FCC compliance: Contrary to XSI’s claims, the multi-band OFDM system is FCC compliant and should not have to reduce its transmit power.

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Study of Potential Victim Receivers Most US government and commercial systems are out-of-band (OOB):

For OOB systems, victim receiver performance is expected to be the same for MBOK & MB-OFDM type UWB interference. MB-OFDM has a slight advantage due to better OOB rejection capabilities.

No impact expected on CW & Pulsed Altimeter systems due to high tolerable UWB TX power limits (NTIA Report: +14 dBm/MHz).

Analog FSS systems are quickly being replaced by digital FSS systems. In 1995, there were 2 million analog FSS systems. In 2002, only 500K. Digital FSS systems are more robust to interference.

ARRL0.001/-/-

420 450

DME Interrogator0.65/-38/-

960 1215

DMETranspon.0.8/-55/-48

1025 1150

1030 1090

ATCRBSTransponder

5.5/-35/-

ATCRBSInterrogator9/-22/-35

ARSR-40.69/-52/-73

1240 1370

11641214

GPS2/-/-

15441545

SARSAT0.8/-60/-57

15601595

GPS2/-/-

PCS0.2/-/-

1.25/-/-

1800 2000

3G5/-/-

1900 2100

DOD-SGLS

2200 2300

ARRL0.001/-/-

2400 2450

NEXRAD0.653/-33/-67

2700 2900

Maritime Radar4 20/-34/-45

3100

CW Altimeter-/37/-

4200 4400

PulsedAltimeter30/26/-

4200 4400

FSS Analog40/-/-

FSS Digital40/-/-

3700

3700

50305091

ARS-9.6531/-37/-57

2700 2900

MBOK BW

OFDM BW

MLS.15/-42/-

SystemIF BW (MHz) / Max. UWB EIRP (dBm/MHz) @ 2m height / Max. UWB EIRP (dBm/MHz) @ 30m height

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3 4 5 6 7 8 910

-4

10-3

10-2

10-1

100

Interference comparison between various UWB waveforms

SINR

Bit

Err

or

Ra

teWhite Gaussian Noise InterferenceMB-OFDM with 3 bandsMB-OFDM with 7 bandsPulsed UWB with 1 MHz PRF

FSS Simulation results 35 MSPS, rate 7/8 coding, no interleaving, Iuwb/N = -6 dB [XSI filing to FCC for

typical operating scenarios, Sept. 2003]

Very little difference between UWB radios under realistic scenarios[Note: SINR=C/(N+Is+Iuwb), Is=satellite intra-system interference]

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Interference and coexistence studies depend on a number of factors: Application dependent variations: expected minimum separation distance between

UWB emitter and victim receiver under realistic usage models, probability of this minimum separation distance seen in reality, pervasiveness of victim receiver

Implementation variations: antenna gain response, available link margin, FEC and other signal processing techniques adopted to mitigate noise and interference

Other interference sources: intra-system interference sources, noise floor of device Allowed interference margins: minimum criteria for interference level and impact on

probability of outage, built-in margin for external interference sources (all systems must expect some level of interference)

Potential interference caused by multi-band OFDM is lower than that generated by impulse radios, which are allowed under FCC rules.

Interference into FSS band

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Interference to Out-of-band Systems

Many of the government systems (FAA, DOD) and commercial systems (GPS, PCS) are out of band (OOB) for the proposed UWB systems. The OOB rejection capability for UWB systems is important when analyzing

interference to these systems.

Since the multi-band OFDM system employs a narrower bandwidth than MBOK, it can achieve better OOB rejection: OFDM has an inherent steep roll-off at the band edges due to modulating narrow

tones (~4 MHz) relative to the occupied bandwidth (528 MHz). To achieve similar roll-off, an MBOK system would require sharp (higher-order) filters,

which can be expensive in terms of die area and insertion loss.

Hence, interference into out of band FAA, GPS, and PCS systems can be much less from MB-OFDM systems than from MBOK systems.

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FCC Chairman Michael PowellKey Steps toward Spectrum Reform*

There is a substantial amount of “white space” out there that is not being used by anybody.

A software-defined radio may allow licensees to dynamically “rent” certain spectrum bands when they are not in use by other licensees.

* “Broadband Migration III: New Directions in Wireless Policy”University of Colorado at Boulder, Oct 30, 2002

Future In-band Interference Mitigation Techniques

International regulatory agencies are supportive of frequency agile solutions to help protect different services in different locations

Recent ITU meeting shows uncertainties still exist around international regulations

Multi-band OFDM is an efficient method for enabling frequency agility

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Submission

HomePlug Power Line Spectral Mask -- A Precedent for Low-Cost “Sculpting” via OFDM Technology

Frequency, MHz

Source: HomePlug Alliance, HomePlug & ARRL Joint Test Report, January 24, 2001

30dB Notches Protect Amateur Radio

OFDM enables simple interference reduction techniques

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Conclusions about FSS: Both multi-band OFDM and WGN waveforms are less harmful than impulse radios, which

are allowed under the FCC. Contrary to XSI’s claims, multi-band OFDM is FCC compliant and should not have to

reduce its transmit power.

Summary: The multi-band OFDM proponents are committed to ensuring that no harmful

interference is caused to potential victim receivers. Both simulations and real experimental testing will continue in order to determine if

anything in the current proposal needs to be changed to help mitigate potential interference: This should be the case for ANY draft proposal adopted by the IEEE.

The combination of multi-banding and OFDM provides a unique capability to tightly control OOB emissions as well as enables spectrum flexibility to protect future systems and differences in international allocations.

Conclusions and Summary

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Comparison Between theMulti-band OFDM and MBOK Proposals

Presenter: Anand Dabak

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“Apples to Apples” Comparison

Similar frequency bands; MB-OFDM 3.1-4.9 GHz, MBOK 3.15-5.15 GHz

Compared multi-band OFDM versus MBOK with respect to: Performance and range in multi-path channel environments. Robustness to interference from a single tone jammer. Analog and RF implementation considerations. ADC precision requirements. Digital complexity.

Comparison based upon widely available information for MBOK system.

Digital architectures for MBOK/DS-CDMA have been selected for the comparison. Expected to provide better performance over analog implementation [slide 8 of

03/0334r2]

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MBOK simulation environment Receiver architectures used for MBOK simulations:

Architecture 2ADC 2.736 GHz,No ADC quantization

ADC 2.736 GHz,No ADC quantization

Chip matched filter (16 fingers)

MBOK demodulator (I, Q)

FEC decoding

Channel estimates

Architecture 1 (**)ADC 2.736 GHz,1 bit ADC

ADC 2.736 GHz,1 bit ADC



FEC decoding

Channel estimates

**: Analogous to the architecture proposed by ParthusCeva in 03/0334r3, ParthusCeva employs a single 1 bit ADC at 5.472 GHz

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MBOK simulation parameters (Architecture 1)Parameters AWGN: Ideal receiver AWGN: Non-ideal Receiver Multi-path Non-ideal Receiver Chip rate 1.368 Gchips/sec 1.368 Gchips/sec 1.368 Gchips/sec

Data rates (Mbps) 114,112,200,224,448 114,112,200,224,448 114,112,200,224,448 Interleaver between MBOK

and Convolutional code 114, 200, 448: None

112, 224: With/Without 114, 200, 448: None

112, 448: With/Without 114, 200, 448: None

112, 448: With/Without Interleaver between MBOK

and Convolutional code Block interleaver Block interleaver Block interleaver

AWGN channel Yes Yes No Channel estimation Ideal Yes Yes Channel estimation

sequence Not applicable (Ideal channel estimation)

Preamble [1] Preamble [1]

Timing error No Yes: ¼ chip Yes: ¼ chip Carrier phase error Ideal Ideal Ideal

Oversampling 2X chip rate 2X chip rate 2X chip rate Filtering Ideal SRRC ( = 0.5) Ideal SRRC ( = 0.5) Ideal SRRC ( = 0.5)

SRRC factor 0.5 0.5 0.5 ADC quantization None Yes: 1 bit Yes: 1 bit

Ch. Est. Quant. None Yes: 4 bit Yes: 4 bit Number of fingers 150 (I, Q at 2X)*** 150 (I, Q at 2X) 150 (I, Q at 2X)

MBOK output Soft: LLR based Soft: LLR based Soft: LLR based Viterbi decoding ML ML ML

Reed-Solomon decoding Yes Yes Yes Target BER for FER = 8% 10-5 10-5 10-5

Reported BER Average BER Average BER Average BER of best 90% of channels

Degradations from packet detection, time/carrier tracking, front end filtering, not included in simulations

***: 150 fingers at I, Q complex are equivalent to 300 fingers in 03/334r3 [1]: 03/0334r3

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MB-OFDM simulation parameters Time tracking, carrier phase tracking, front end filtering, ADC quantization

losses included in the simulations

Parameters AWGN Ideal receiver AWGN Non-ideal Receiver Multi-path Non-ideal Receiver MB-OFDM mode 3-band 3-band 3-band Data rates (Mbps) 110, 200, 480 110, 200, 480 110, 200, 480 AWGN channel Yes Yes No

Channel estimation Ideal Yes Yes Timing error No Yes (+/- 20 ppm) Yes (+/- 20 ppm)

Carrier phase error No Yes (+/- 20 ppm) Yes (+/- 20 ppm) Sampling rate 528 MSPS 528 MSPS 528 MSPS

ADC quantization None Yes: 4 bits Yes: 4 bits Channel estimation

quantization None Yes: 8 bit Yes: 8 bit

Length of FFT 128 128 128 Viterbi decoding ML ML ML

Target BER for FER = 8% 10-5 10-5 Reported BER Average BER Average BER Average BER of best 90% of

channels

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Simulation parameters comparison

Degradations:

MBOK simulations results are optimistic.

Calibrated M-BOK performance (see backup slide 62).

Degradations Multi-band OFDM MBOK

Included in the simulations Packet detection Channel estimation Time/carrier tracking ADC quantization DAC clipping Front-end filter

Channel estimation ADC quantization Timing offsetChannel estimate quantization

NOT included in the simulations

Packet detection Time/carrier tracking Front-end filter

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Multi-path Performance Comparison

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Performance for 112/110 Mbps

Multi-band OFDM outperforms MBOK with 150 finger RAKE by about 1 dB in multi-path channel environment (CM3).

MB-OFDM outperforms MBOK by about 1 dB.

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Performance for 224/200 Mbps


MB-OFDM outperforms MBOK by ~5 dB

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Error Floor for MBOK The MBOK system hits an error floor in multi-path channel environments for data

rates of 200 Mbps (CM3) and 448 Mbps (CM2).

Error floor for MBOK (does not reach 10-5)

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Performance: 16 finger RAKE

MBOK performance improves marginally with 16 finger RAKE & no ADC quantization. But,

112/114 Mbps MBOK is ~1.5 dB worse than 110 Mbps MB-OFDM. 224/448 Mbps MBOK is about 4 to 6 dB worse than 200/480 Mbps MB-OFDM. 200 Mbps MBOK hits an error floor.

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Range Comparisons

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Range in AWGN Transmitter backoff, propagation loss calculations given in backup. Multi-band OFDM has better range than MBOK in an AWGN environment.

20 m (110 Mbps MB-OFDM) versus 16.8 m (112 Mbps MBOK) 14 m (200 Mbps MB-OFDM) versus 12.6 m (224 Mbps MBOK) 7.8 m (480 Mbps MB-OFDM) versus 6.8 m (448 Mbps MBOK)

114 Mbps

200 Mbps

112 Mbps

448 Mbps

224 Mbps

110 Mbps

200 Mbps

480 Mbps

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Range in Multi-path

Multi-band OFDM has significantly better range than the MBOK system. 11.6 m (110 Mbps MB-OFDM) versus 9.4 m (112 Mbps MBOK) 6.8 m (200 Mbps MB-OFDM) versus 3.9 m (224 Mbps MBOK) 2.6 m (480 Mbps MB-OFDM) versus 1.2 m (448 Mbps MBOK)

114 Mbps

200 Mbps

112 Mbps

448 Mbps

200 Mbps

110 Mbps

224 Mbps

480 Mbps

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Single Tone Interferer

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Single Tone Interferer Simulation Results

Assumption: receiver operates 6 dB above sensitivity (15.3a criterion) For MBOK need SIR = 4 dB for architecture #1 and SIR = –1 dB for

architecture #2.

Architecture 1 Architecture 2

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Single Tone Interferer Comparison For a fair comparison between two systems, we assume there is no analog

filter notches for either system. MB-OFDM results in backup [03-268r1P802-15_TG3a-Multi-band-CFP-Document.doc]

Multi-band OFDM system out performs MBOK architecture #2 by 7 dB, and MBOK architecture #1 by 12 dB.

May be possible to use DSP techniques for MBOK to improve its performance, however the complexity of MBOK receiver will then increase.

System Min. required SIR 15.3a criterion: SIR = -3 dB

DS-CDMA Architecture 1: 1 bit ADC, 150 finger rake

4 dB Fails to meet the minimum required criterion by 7 dB

DS-CDMA Architecture 2: no ADC quantization, 16 finger rake

-1 dB Fails to meet the minimum required criterion by 2 dB

MB-OFDM -8 dB Outperforms the minimum required criterion by 5 dB

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ADC Requirements for an MBOK System

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ADC requirements for MBOK architecture 2

Multi-path simulations: CM3 for 224 Mbps, CM2 for 448 Mbps 3 bits required for 224 Mbps, 4 bits required for 448 Mbps

MBOK architecture 2, 224 Mbps MBOK architecture 2, 448 Mbps

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ADC Requirement Comparison

Multi-band OFDM requires a lower sampling rate ADC than the MBOK system.

For rates less than 224 Mbps: MB-OFDM requires an ADC running at 528 MHz with 4 bits precision. MBOK requires an ADC running at 2736 MHz with 3 bits precision.

MBOK may employ chip rate sampling, but performance will be worse.

For rates greater than 224 Mbps: MB-OFDM requires an ADC running at 528 MHz with 5 bits precision. MBOK requires an ADC running at 2736 MHz with 4 bits precision.

MBOK may employ chip rate sampling, but performance will be worse.

The ADC requirements for the multi-band OFDM system is simpler than that required for the MBOK system architecture 2.

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Analog/RF Implementation Comparison

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Is RF sampling feasible for MBOK ?

Proposed RF sampling architecture for MBOK in 03/334r3.

Two crucial issues: Out of band interference rejection IEEE 802.11a. RF gain feasibility.

Filter LNA 5.472 GHz 1 bit ADC


1.368 GHz complex samples*

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IEEE 802.11a rejection

For an IEEE 802.11a device to operate within 1 meter of UWB, the IEEE 802.11a rejection required is a total of ~60 dB.

With an off-chip filter, one can achieve ~ 30 dB of rejection. Still need another ~ 30 dB of rejection.

Only other possibility: Put another off-chip filter after LNA.

This implies: Higher bill of material, special components: Higher cost. Increased off-chip external components: Cannot have an integrated solution.

3.1 GHz 10.6 GHz5.1 GHz 6.5 GHz

802.11(a)

MBOK UWB

Filter(offchip)

LNA 5.472 GHz 1 bit ADC


1.368 GHz complex samples\Filter

(offchip)

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Submission

RF gain feasibility for MBOK

The sensitivity for 110 Mbps MBOK is -80 dBm

Even for a 1 bit ADC, an RF sampling architecture for MBOK will require gain amplifiers with a total gain of 60 dB at an RF center frequency of 4.1 GHz and bandwidth of 1.6 GHz.

Such wideband, high gain amplifiers at RF frequencies are very difficult to implement in practice. Oscillations: Stability problems Yield: Time to market

Hence it may be very risky in practice to implement the RF sampling architecture proposed in 03/334r3

Filter (2 dB loss)

LNA ~ 15 dB gain

5.472 GHz 1 bit ADC

GA ~ 45 dB gain, center freq : 4.1 GHzbandwidth: 1.6 GHz21 V

Voltage has to be in the order of ~ 20 mV

Block not shown in 03/334r3, but will be needed in practice

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A mixer-based architecture for front end RF is feasible for the MBOK system.

Need a 750 MHz wide low pass filter with sharp cutoff: MB-OFDM needs 250 MHz filter

Need a broad band GA/VGA (750 MHz) for MBOK: MB-OFDM needs 250 MHz wide VGA

Need 1 bit ADC at 2736 MHz for architecture 1 and 3-4 bit ADC at 2736 MHz for architecture 2: MB-OFDM needs 528 MHz 4-5 bits ADC.

MB-OFDM needs to generate multiple frequencies while MBOK needs to generate a single frequency.

Mixer based architecture for MBOK System

Pre-SelectFilter

LNA

sin (2fct)

cos(2fct)

I

Q

LPF

LPF

GA/VGA

GA/VGA

ADC 2.736 GHz,1/3/4 bit ADC

ADC 2.736 GHz,1/3/4 bit ADC

750 MHz bandwidth

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Comparison of RF/Analog Complexity

Qualitative comparison of RF/Analog complexity between MB-OFDM and MBOK.

(1) Architecture 1: 1 bit ADC Quantization.(2) Architecture 2: 3-4 bit ADC Quantization.

ADC Feasibility

ADC Complexity

VGA

Frequency Synthesis

Low-pass Filter

Front-end Filter/LNA/Mixer

MBOK Advantage

NeutralMB-OFDMAdvantage

Criteria

12

12

Architecture RF Sampling Mixer to Baseband Architecture

MBOK Architecture #1

Extremely Difficult

Feasible

MBOK Architecture #2

Extremely Difficult

Very Difficult

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Digital Complexity Comparison

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Digital RX Block Diagram for MBOK

Assumption: 130 nm technology at 85.5 MHz (per 03/334r3-03/447r0). We estimated the complexity for the major blocks (shaded blocks) of

the MBOK system.

Chip matched Filter (150/16 fingers)2.736 GHz

complex samples in

1.368 GHz complex


Time tracking

Carrier phase correction

Carrier tracking

FEC decoding

Preamble detection/ synchronization

Channel estimation

The implementation complexity of shaded blocks was calculated. The implementation complexity for other blocks was nottaken into account

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Chip Matched Filter (CMF) Complexity Assumption: 150 fingers with a 1-bit ADC. CMF needs about 225,000 gates (85.5 MHz clock)

In 03/334r3, the estimated gate is 75,000 (85.5 MHz). Difference occurs because 03/334r3 did not take into account that both I & Q

outputs (224 Mbps mode is QPSK) are needed from the CMF output.

In the latest document [03-0447] it is estimated as 49,400 (171 MHz clock) for real CMF and 90,200 (171 MHz clock) for complex CMF For a fair comparison should use the same clock frequency.

CMF blocks (112, 224 Mbps rates)

Gates/device Total XSI/Parthus Calculations 03/447r0

(85.5 MHz) 4800 (I, Q), 4 bit adders 27 gates/4 bit adder 129,600 163,200 4800 (I, Q), Or operation 4 gates/4X1 bit OR 19200 Not taken

9600 (I, Q), And operation 4 gates/4X1 bit And 38400 Not taken 4800 additional registers between

stages (for multiplexing clock) 4 gates/register 19200 Not taken

Misc. 20,000 17,200 Total CMF gates ~225,000 180,400

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Complexity for MBOK Architecture #1 Assumption: 130 nm, 85.5 MHz clock. Backup slides contains calculations for MBOK decoder and synch block.

To make a fair comparison with MB-OFDM system, we need to adjust to clock of MBOK to 132 MHz: MBOK system requires ~400K gates (@132 MHz). Multi-band OFDM system needs 295K gates (@132 MHz) [03-0343].

MBOK system requires 35% more baseband complexity when compared to the multi-band OFDM system.

Component Low band Size (85.5 MHz) 03/447r0 & 03/334r3 calculations Matched filter 225K 180 K

Viterbi decoder 108K 90 K Reed-Solomon decoder 20K (included above)

MBOK demodulator 61K Not stated explicitly Synchronization 177K Not stated explicitly

Channel estimation 24 K 24 K Other Miscellaneous including

RAM 30 K 87 K

Total gates with synchronization 624 K 381 K

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Summary of Comparison Results Did a fair comparison of multi-band OFDM versus MBOK in terms of

performance, complexity, implementation feasibility, interference, based upon available data on the MBOK proposal.

The proposed direct RF sampling architecture (MBOK arch #1) in 03-334r3 may not be feasible in practice.

MB-OFDM has a clear advantage over MBOK in terms of; Significantly better range in multi-path (20% – 120% increased range) Significantly better robustness against interference (7 – 12dB better performance). Simpler hardware requirements (lower rate ADC’s, lower bandwidth VGA’s) Lower digital complexity (~25% less number of gates)

November 2003


doc.: IEEE 802.15-03/449r0

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Conclusions Pursuance of the best technical solution has led to the current MB-OFDM proposal

Current proposal is superior to all other proposals presented to the Task Group Authors from 17 affiliated companies/organizations and supporters from 19 others All these companies, which represent the vast majority of the industry, have spent

significant resources to evolve to the best technical solution

UWB and FCC Both MB-OFDM and WGN waveforms have similar interference properties and are less

harmful than impulse radios, which are allowed under the FCC rules. Multi-band OFDM does not generate any more interference than anticipated by FCC.

MB-OFDM is superior to MBOK based on an apples to apples comparison Multi-band OFDM is lower complexity, lower power consuming, more feasible, better

performing and more robust to interference when compared to MBOK solution

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Backup

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Over the past few weeks several parties have met with the staff of the Federal Communications Commission Office of Engineering and Technology to discuss how the Commission’s rules for Ultrawideband devices might be applied for certain signal formats that are being considered by IEEE 802.15.

OET believes it is premature to make any determination as to the appropriate measurement methods for particular signals because this matter is under active discussion in IEEE. In this regard, we have no immediate plans to respond to the XSI/Motorola request for a declaratory ruling.

We urge that IEEE perform technical analyses to ensure that any UWB standard it develops will not cause levels of interference beyond that already anticipated by the rules.

This information will be needed to support any necessary FCC rules interpretations or other appropriate action for the chosen standard.

The FCC has had a long history of working cooperatively with the IEEE 802 committee in addressing any regulatory issues that may arise relative to standards. We recommend that IEEE proceed with its standards development process and that the committee address any questions to us at a later time when it has formed a specific proposal.

FCC’s response*

Summary of Discussions with FCC Staff Concerning IEEE 802.15 Deliberation On Standards for Ultrawideband devices

*:E-mail sent by Julius Knapp, Deputy Chief, OET, FCC to XSI/Motorola and MB-OFDM proponents on September 11th, 2003

November 2003


doc.: IEEE 802.15-03/449r0

Submission

UWB Bandwidth and Peak Radiated Emissions within a 50 MHz BW

Radio Sample 1

Test Distance: 1mDetector: PEAKRBW/VBW: 3 MHz/3 MHzMeas. Time: 1 msEmissions: < LimitUWB BW: > 500 MHz

Note: Data normalized to 3m test environment and 50 MHz RBW for limit comparison.

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Radiated Emissions UWB

Radio Sample 2

Test Distance: 1mDetector: RMSRBW/VBW: 1 MHz/3 MHzMeas. Time: 1 msEmissions: < Limit

Note: Data normalized to 3m test environment for limit comparison.

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Emissions in GPS Bands

Radio Sample 1

Test Distance: ConductedDetector: RMSRBW/VBW: 1 kHz/3 kHzMeas. Time: 1 msEmissions: < Limit

Note: Limit line is most stringent at 3m distance. No emissions above noise floor in radiated or worst case conducted measurement mode.

November 2003


doc.: IEEE 802.15-03/449r0

Submission

MBOK simulated data rates

For architecture 1 simulation conditions as close to the receiver proposed in 03/334r3

FEC RateQuadratureSymbol RateConstellationInfo. Data Rate

Yes

Yes

Yes

No

Yes

R = 0.87

R = 0.44

R = 0.87

R = 0.44

R = 0.50

64-BOK

64-BOK

4-BOK

64-BOK

4-BOK

448 Mbps

224 Mbps

200 Mbps

112 Mbps

114 Mbps

42.75

42.75

57

42.75

57

R=0.44 is concatenated ½ convolutional code with RS(55,63) R=0.50 convolutional code R=0.87 is RS(55,63)

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Calibration of MBOK decoder 8-BOK BER performance matches with [03-334r3]

4-BOK gives no performance gain over AWGN

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Performance for 114 Mbps


MB-OFDM outperforms MBOK by about 2 dB.

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Results for 112 Mbps (No interleaver between MBOK and Viterbi)

MB-OFDM outperforms MBOK 150 finger rake by ~ 2 dB

Improved performance of MB-OFDM over MBOK (~ 2 dB)

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Performance for 224 Mbps The performance of the MBOK system degrades in the absence of an interleaver

between the MBOK demodulator and the Viterbi decoder

MBOK reaches an error floor in multi-path channel environment with a 150 finger RAKE.

Error floor for MBOK (does not reach 10-5)

November 2003


doc.: IEEE 802.15-03/449r0

Submission

MBOK simulation parameters (Architecture 2)

Degradations from packet detection, time/carrier tracking, front end filtering, not included in simulations

Parameters Case 3: Multi-path Actual ReceiverChip rate 1.368 Gchips/sec

Data rates (Mbps) 114,112,200,224,448Interleaver between MBOK and

Convolutional code114, 200, 448: None

112, 448: With block interleaverAWGN channel No

Channel estimation YesChannel estimation sequence Preamble [1]

Timing error* Yes: ¼ chipCarrier phase error* Ideal

Oversampling 2X chip rate: 2.736 GHzFiltering Ideal SRRC ( = 0.5)

SRRC factor 0.5ADC quantization No ADC quantization

Ch. Est. Quant. Yes: 4 bitNumber of fingers 16, 5

MBOK output Soft: LLR basedViterbi decoding ML

Reed-Solomon decoding YesTarget BER for FER = 8% 10-5

Reported BER Average BER of best 90% of channels

Changes from simulations forarchitecture 1

November 2003


doc.: IEEE 802.15-03/449r0

Submission

5 finger rake results with no ADC quantization

5 finger rake for 114, 112 Mbps, hence the MBOK atleast “works” in practice for these data rates, despite significantly bad performance (~ 6 dB worse) with respect to MB-OFDM. For other data rates, 5 finger rake hits an error floor.

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Equalizers for MBOK Performance for MBOK could be improved using equalization

techniques.

Linear equalizers Equalizer length would probably have to be in the same order as the

number of rake fingers ~ 150 taps for architecture 1 ~ 16 taps for architecture 2

Training large number of taps requires longer preamble and adds to the complexity.

Decision feedback equalizers (DFE) The complexity of DFE’s for 64-BOK can be significant Error propagation could be significant at operating Eb/N0 (~1 dB at the

input of the decoder).

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Transmitter backoff Need to take into account the transmitter backoff for range

calculations For fair comparison, assume the same RF front end noise figure for

MB-OFDM and MBOKMB-OFDM DS-CDMA, 4-BOK DS-CDMA, 32 BOK

Transmit Power -10.3 dBm -9.9 dBm -9.9 dBmTransmit Back-off 0 dB 2.1 dB ~ 1dB

Path loss @ 1m 44.2 dB 44.4 dB 44.4 dBReceive Power @ 1m -54.5 dBm -56.4 dBm -55.3 dBmLoss (AWGN) with

respect to MB-OFDM

0 dB 1.9 dB 0.8 dB

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Range comparison Take into account transmitter backoff, propagation loss AWGN:

Multi-path

Range in AWGN scenarioData rates (Mbps) DS-CDMA MB-OFDM

114 13.5 m112 /110 16.8 m 20 m

200 6.3 m 14 m224 12.6 m

448/480 6.3 m 7.8 m

Data rates (Mbps) DS-CDMA:Architecture 1

DS-CDMA:Architecture 2

MB-OFDM

114 (CM3) 7.7 m 7.2 m N/A112/110 (CM3) 9.4 m 9.0 m 11.6 m

200(CM3) 0 m ? 0 m? 6.8 m224 Mbps (CM3) 3 m 3.9 m N/A

448/480(CM2) 0 m ? 1.2 m 2.6 m

November 2003


doc.: IEEE 802.15-03/449r0

Submission

MB-OFDM results [03268r1P802-15_TG3a-Multi-band-CFP-Document.doc ]

MB-OFDM can erase tones in digital Required SIR > - 8 dB

November 2003


doc.: IEEE 802.15-03/449r0

Submission

MBOK demodulator complexity Since the phase is unknown before the MBOK demodulation, need to

do MBOK correlation for both CMF output I, Q with MBOK I, Q codes.

MBOK demodulation blocks Gates/device Total [email protected] MHz4 (I, Q with each of the I, Q

MBOK codes)X32, length 32 4bit [email protected] MHz rate

25 gates/adder 51,200

Other Miscellaneous registers,buffers, 20% overhead

10,240

Total gates 61,440

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Synchronization/Preamble detection complexity

The MB-OFDM system employs a preamble of 312.5 ns and length 128 samples long.

A fair comparison would require similar synchronization performance of the correlator for MBOK and for MB-OFDM system.

MBOK employs about 3X the bandwidth of the MB-OFDM single band, implying multi-path the MBOK pulses would be about 3X lower in energy compared to the MB-OFDM, as seen by the correlator ****.

Hence in order to achieve an acquisition performance similar to MB-OFDM, we expect that the MBOK has to do a correlator of length 1 microsecond => 1368 chips long

However, for reduced complexity of MBOK, assume a length 553 correlator only as in [03123r6P802-15_TG3a-ParthusCeva-CFP-Presentation.ppt]

***: Design challenges for very high data rate UWB systems Somayazulu, V.S.; Foerster, J.R.; Roy, S.; Signals, Systems and Computers, 2002. Conference Record of the Thirty-Sixth Asilomar Conference on , Volume: 1 , Nov. 3-6, 2002 Page(s): 717 -721

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Synchronization/Preamble detection complexity (2) Assume that a 1 bit input shift register needs 4 gates per bit Assume the 553 length correlator has 1 bit input. The adder tree for the correlator

grows in the number of bits. Assume 6 gates/adder (optimistic estimate) Total gates of 177 K for synchronization

Synchronization/Preambledetection

Gates/device Total [email protected]

553 complex shift register @1.368 GHz

4 each on I, Q 71K

553 complex 1 bit adds @1.368 GHz

6 gates each on I, Q 106K

Total gates 177 K

November 2003


doc.: IEEE 802.15-03/449r0

Submission

Digital complexity of Architecture 2

Needs 16 4-bit complex multiplies: Assuming 800 gates/4-bit complex multiply gives 205K

Assume a 1 bit synchronization similar to architecture 1 Other complexity is the same as architecture 1 130 nm, 85.5 MHz clock

Component Architecture 1 Architecture 2

Matched filter 225K 205KViterbi decoder 108K 108K

Reed-Solomon decoder 20K 20KMBOK demodulator 61K 61K

Synchronization 177K 177KChannel estimation 24 K 24 K

Other Miscellaneousincluding RAM

30 K 30 K

Total gates withsynchronization

624 K 604 K

Documents

Doc.: IEEE 802.15-03/449r0 Submission November 2003 A. Dabak, TI, R. Aiello, Staccato, et al.Slide 1 Project: IEEE P802.15 Working Group for Wireless Personal