doc.: ieee 802.15-03/449r0 submission november 2003 a. dabak, ti, r. aiello, staccato, et al.slide 1...
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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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 2
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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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 4
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 5
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 6
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 7
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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…
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 8
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 9
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 10
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Submission
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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 11
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Submission
FCC Compliance of Multi-band OFDM
Presenter: Anand Dabak
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 12
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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.”
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 13
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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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 14
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 15
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Submission
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]
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 16
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 17
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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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 18
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 19
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 20
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 21
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Submission
Comparison Between theMulti-band OFDM and MBOK Proposals
Presenter: Anand Dabak
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 22
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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]
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 23
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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
Chip matched filter (150 fingers)
MBOK demodulator (I, Q)
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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 24
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 25
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 26
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 27
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Multi-path Performance Comparison
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 28
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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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 29
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Performance for 224/200 Mbps
Multi-band OFDM outperforms MBOK with 150 finger RAKE by about 5 dB in multi-path channel environment (CM3).
MB-OFDM outperforms MBOK by ~5 dB
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 30
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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)
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 31
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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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 32
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Range Comparisons
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 33
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 34
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Submission
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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 35
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Single Tone Interferer
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 36
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 37
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 38
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Submission
ADC Requirements for an MBOK System
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 39
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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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 40
doc.: IEEE 802.15-03/449r0
Submission
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.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 41
doc.: IEEE 802.15-03/449r0
Submission
Analog/RF Implementation Comparison
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 42
doc.: IEEE 802.15-03/449r0
Submission
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
Chip matched filter (300 fingers)
1.368 GHz complex samples*
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 43
doc.: IEEE 802.15-03/449r0
Submission
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
Chip matched filter (300 fingers)
1.368 GHz complex samples\Filter
(offchip)
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 44
doc.: IEEE 802.15-03/449r0
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
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 45
doc.: IEEE 802.15-03/449r0
Submission
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 46
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 47
doc.: IEEE 802.15-03/449r0
Submission
Digital Complexity Comparison
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 48
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
MBOK demodulator (I, Q)
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 49
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 50
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 51
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 52
doc.: IEEE 802.15-03/449r0
Submission
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 53
doc.: IEEE 802.15-03/449r0
Submission
Backup
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 54
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 55
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 56
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 57
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 58
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 59
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 60
doc.: IEEE 802.15-03/449r0
Submission
Performance for 114 Mbps
Multi-band OFDM outperforms MBOK with 150 finger RAKE by about 2 dB in multi-path channel environment (CM3).
MB-OFDM outperforms MBOK by about 2 dB.
November 2003
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 61
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 62
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 63
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 64
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 65
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 66
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 67
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 68
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 69
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 70
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 71
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
A. Dabak, TI, R. Aiello, Staccato, et al.Slide 72
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