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November 2004 IEEE P802.15-04/0638r4

IEEE P802.15Wireless Personal Area Networks

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

Title San Antonio Meeting Minutes

Date Submitted

18 November 2004

Source [Gerald W. Wineinger][TI][Dallas, Texas]

Voice: [214 480 1013]Fax: [214 480 6662]E-mail: [[email protected]]

Re: 802.15.3a Task Group San Antonio Meeting Minutes

Abstract Minutes of Task Group 3a in San Antonio

Purpose Minutes of Task Group 3a in San Antonio

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.

CONTENTS

Monday, 15 November 2004Session 1 - 2

Tuesday, 16 November 2004Sessions 3

Wednesday, 17 November 2004Sessions 4 - 7

Thursday, 18 November 2004Sessions 8 - 9

Submission Gerald W. Wineinger, TI

November 2004 IEEE P802.15-04/0638r4

MONDAY, 15 NOVEMBER 2004

Session 1

The task group (TG) chairman, Bob Heile, called the session to order at 2:12 PM

The chairman made the following announcements:

MMAC (Multimedia Mobile Access Communication System) Forum is organizing a Task force for interference for UWB – asking for

Call for contributions:

Contribution Presentation WorksheetItem Name Doc title Ref Time

1 WELBORN Extended CSM 341 30

2 ZHANG SSA pulse waveform 499 30

3 CHOI Implementation of virterbi decoder 467 20

4 GAFFNEY Performance of MB OFDM in fading channel 484 30

5 CORRAL Multi-band OFDM Interference on In-band QPSK… 451 45

6 LARSSON Impact of MB-OFDM and DS-UWB interference… 609 35

7 BARR FCC waiver request overview 624 30

8 MCLAUGHLIN DS-UWB simulation results 483 30

9 AIELLOFacts and misconceptions about MBOA waiver request 627 30

TOTAL 280

The chair asked for approval of the agenda document 15-04-0577-04-003a; John Barr made a motion to accept the agenda and Ian Gifford seconded it. The agenda was approved by unanimous consent.

The chair then asked for approval of the minutes document 15-04-0497-04-003a Motion to accept the minutes was from Ian Gifford, seconded by Ian Gifford. The minutes were then approved by unanimous consent.


November 2004 IEEE P802.15-04/0638r4

Matthew Shoemake started the discussion on no vote comments received stating that the following presentations are in document: 15-04-0641-00-003a

Joy Kelly then covered the following points from document 15-04-0641-00-003a: Overview of FCC Compliance / Interference Summary of main opposing comments & claims

o MB-OFDM will increase the potential for interference Not true, as will be shown here

o Granting the Waiver will give MB-OFDM an unfair advantage (increased range) relative to other UWB technologies

Not true, even by opposer’s claimso Waiver will ‘open the door’ to other systems seeking relief from the rules

Scope of Waiver is narrow and does not impact most of the FCC ruleso FCC should wait for more data and delay making a ruling

Reply comments provide comprehensive data; no new information will come from more tests on the 3-band MB-OFDM waveforms

o Waiver is not in the public interest and will negatively impact small businesses MBOA SIG represents 170+ companies, including many small start-

upso MBOA technical justification is filled with errors

Inclusion of WGN in comparisons ‘masks’ MB-OFDM interference potential

Thermal noise and other interference sources are a reality Wrong BER operating point

BER criterion based on quasi-error free performance Field measurements are invalid

Same position and separation distance tests are valid and reflect real systems

Simulations results are wrong because they included noise Noise is a reality and simulation results are supported by lab

and field measurements APD analysis is erroneous

Shown to be technically accurate using NTIA code Summary of technical points

o No greater interference than systems allowed by FCC ruleso Bandwidth of information-carrying tones is 503.25 MHzo MB-OFDM technology advantages

Band switching (the multi-band concept) OFDM advantages Spectrum flexibility will be necessary to enable worldwide

interoperability and to adapt to future spectrum allocations

No greater interference:o C-band satellites


November 2004 IEEE P802.15-04/0638r4

o 802.11a deviceso Other UWB deviceso No risk of aggregation

During Joy’s presentation John Barr asked that she turn off her instant messaging. She attempted too, but it continued..

MBOA C-band Satellite field test resultso Same Position Testingo Safe Distance Tests

Interference to 802.11ao Test Set-up for Interference Measurements to 802.11ao Test Descriptiono Measurement results

Example BER results for 802.11a comparing MB-OFDM & AWGN 802.11a AGC Performance in the Presence of MB-OFDM Transmission 802.11a Packet Detection & AGC Performance in Presence of AWGN & MB-OFDM

Interference MB-OFDM Interference Impacts to 802.11a Systems: Conclusions

o Measurement results already presented to this IEEE body confirm that: MB-OFDM signal and AWGN have similar interference impact to

IEEE802.11a receiver MB-OFDM signal does not adversely affect packet detection and AGC

convergence performance of IEEE802.11a devices Opponents’ Claims regarding MB-OFDM Interference to other UWB systems

o Freescale states (4.4.2, p. 23 of “Technical Analysis …”): ‘Other UWB receivers will be injured by the MB-OFDM emissions at least as much and often more than all the other victim systems since their bandwidths are so similar. While on its face, one would expect the 6dB higher emission limits to single out MB-OFDM devices for a 2X range advantage, the actual outcome is even worse. The noise floor of all other UWB devices would be raised far more by MB-OFDM devices than other classes of UWB devices.’

o Pulse-Link states in Section III of their “Comments …” : ‘Granting the waiver would allow the MBOA radio to more successfully jam the DS-UWB radio since it will be allowed an increase of power in band.’

o TimeDerivative states: ‘This additional power poses a significant additional risk to other UWB communications equipment.’

o No evidence has been shown to support these claims. Reality: MB-OFDM Interference to other UWB systems

o On the contrary, consider the following example: Assume an MB-OFDM signal which occupies a total bandwidth of 3*528

= 1584 MHz


November 2004 IEEE P802.15-04/0638r4

o peak power spectral density (PSD) during the OFDM symbol ‘on’ time is 5.8 dB above average PSD

o occupied bandwidth of one symbol is ~500 MHz. Evaluate interference experienced due to this signal by an impulse radio

system occupying the same total bandwidth of 1584 MHz (for comparison, Freescale’s proposed DS-UWB system defines impulse radio modulation using impulses of bandwidth 1320 MHz and a PRF of 220 MHz to deliver a data rate of 110 Mbps.).

Assume interference much higher than system noise. At any given instant, one 500 MHz portion of impulse radio’s occupied

band is impacted by an MB-OFDM symbol Impulse radio receiver matched filter integrates all interference power over

the full bandwidth of 1584 MHz. Thus, the total instantaneous interferer power[1] at the output of a 1584

MHz matched filter is IMB-OFDM = (-41.3 + 5.8) dBm/MHz + 10*log10(500) MHz = -8.5 dBm [1] Instantaneous interference power refers to the maximum interference

power to be expected while the interference source is active or ‘on’. total instantaneous interferer power at the matched filter output from

another impulse UWB radio system occupying the same 1584 MHz bandwidth would be

IDS-UWB = (-41.3) + 10*log10(1584) = -9.3 dBm MB-OFDM system offers at worst 0.8 dB higher potential interference in

this example Furthermore, if we consider a more realistic set of conditions, this modest

impact would be reduced still further.o including system noise in addition to the interferenceo Accounting for target DS-UWB system FEC protection

MB-OFDM systems will not increase aggregate interference levels No greater interference:

o Comparisons of various UWB waveforms impact to a generic wideband DVB receiver

Victim Receiver BER Criterion for Digital Video Fundamental assumptions:

What is the right BER criterion? Fundamental assumptions: System Noise must be considered in the analysis Noiseless 7/8-Rate Coded Results Impulsive Interference and FEC ¾-rate Coded Results (with noise) ½-rate Coded Results (with noise) LAB Measurement Results

o Results show that the order of interference impact starting with most benign is: AWGN


November 2004 IEEE P802.15-04/0638r4

3MHz PRF impulses Cyclic Prefix MB-OFDM Zero Prefix MB-OFDM 1MHz PRF impulses

Conclusions on Interference Impact on Wideband DVB Receivero Under realistic, worst-case scenarios, MB-OFDM produces consistently less

interference than a class of impulse radios already allowed by the rules

John Barr again asked that Joy turn off her instant messaging during her presentation due to the popping up of new incoming messages.

No greater interference: APD Analysis

Variation with I/Nsys ratio Variation with Victim Rx BW Summary of APD results

o APD analysis is correct and verified using NTIA codeo APD results for various receiver bandwidths and different TFI codes provided

in back-up slides for more information In bandwidths of 4MHz or less, the MB-OFDM waveforms are nearly

identical to an ideal AWGN source for any given probability. For large bandwidths, the APDs are almost identical regardless of

which TFI code is used (1,2,3,1,2,3 or 1,1,3,3,2,2). MB-OFDM Power Levels MB-OFDM Bandwidth MB-OFDM Technology Advantages for Coexistence with Existing & Future Services Benefits of MB-OFDM Systems Coexistence Benefits of MB-OFDM Systems No other UWB technology can achieve the level of spectrum flexibility provided by

MB-OFDM and still meet stringent market requirements (low cost, complexity, power consumption)

The session recessed at 3:31 PM

Session 2

The task group (TG) chairman, Bob Heile, called the session to order at 4:02 PM

Questions on Joy Kelly’s presentation covered the following points:Answered by Joy Kelly and Charles Razzell:

Publicly available documents from FCC APD analysis and characteristics of a particular receiver/victim


November 2004 IEEE P802.15-04/0638r4

NTIA – APD plots & bit error rate MB-OFDM Interference Average-Power Compliance – exact measurement Out of band emissions Measurement of interference with C-Band systems Satellite Industry approval Opponents reference – commenter Filing to FCC – Oct. 21, 2004, perhaps the group could have seen this sooner, and are

publicly available Document 268r4 vs. document 493r1 – what document will be referring to during

confirmation – 493r1 was an updated document built from 268r4 vs. MBOA MBOA v1.0 spec. – not part of IEEE Coexistence and the spectral density – spectrum shaping presented by TI at an invited

conference – using software or digital hardware Software defined radio possibility, If the current FCC regulations do not allow this –

how will we proceed? If deployed today 500Mhz bandwidth is required. Such flexibility is attractive.

Scope of waiver – wave form specified is a three band waveform, it affects the measurement procedures – see the filing attachments A, B, & C

AWGN Power Interference – measurement outside of MBOA Peak power limit – 1 Mhz reference Dropping tones is not a good and the best methods might be sub-gigahertz, both

proposals need to understand coexistence Interleaving 3 bands sequenced in time provides 1.5 GHz spectrum use for improved

diversity relative to not shifting Notching – out of band emissions

Matthew Shoemake then presented the following points from document 15-04-0641-00-003a:

Support of 15.3 MACo The MultiBand OFDM PHY proposal is designed to work with the IEEE

802.15.3 MACo The proposers of the MB-OFDM solution are not aware of any issues that

would prohibit operation of the MB-OFDM PHY with the IEEE 802.15.3 MAC

o If the commenter has specific technical concerns about interface of the MB-OFDM proposal to the IEEE 802.15.3 MAC, those detailed comments are solicited

There’s a different MACo IEEE can not control external organizations nor should that be our goalo The goal of IEEE 802.15.3a is to help organizations and companies by setting

standards, not to force anything upon them


November 2004 IEEE P802.15-04/0638r4

o The existence of multiple MACs should not be a distraction to the IEEE 802.15.3a deliberations

o IEEE 802.15.3a can do a service to the industry by confirming a new PHY standard

WiMedia Certificationo The success of a standard often depends on interoperability testing and

certificationo The IEEE 802 Standards body has abdicated responsibility for testing and

certifying compliance of productso Given that, there is no direct control over organizations such as Wi-Fi,

DOCSIS, WiMedia, WiMAX, UNH, etc.o IEEE standards are intended to help companies and the population as a whole

including organizations like WiMediao The IEEE should be supportive and appreciative of external organizations that

test and certify IEEE standards based products

Questions were answered on the following points:

Standards organizations outside the IEEE o WiMedia – trying to look at the actual applications and made a choice outside

of IEEE – Different MAC – discussion was cut off

The chair reminded the group that outside organizations have nothing to do with IEEE decisions and that we are making decisions on the technical achievement and merit of meeting the PAR.

Including reply document with current proposal – how do we deal with comments?o Regulations are not in place yet.

IEEE 802.15.3a Phy standard will work with 15.3 MAC, if it works with other MACS it is not important here

Possible multi – phy Premises behind comments on 802.15.3 MAC questions – alternate physical layers, is

there any problem behind choosing a solution based on working with inside IEEE and outside IEEE.

Alternative – MBOA MAC merged into IEEE

Joe Decuir then presented the following points on location awareness document 15-04-0641-00-003a:

Ranging and Location Awarenesso MB-OFDM must have a clear, satisfactory solution to solve the location

awareness problem.


November 2004 IEEE P802.15-04/0638r4

o MB-OFDM proposal is lacking in acceptable location awareness functionality.

MB-OFDM PHY supports range measurementso Ranging is one-dimensional location awarenesso The MB-UWB PHY supports ranging using Two Way Time Transfer algorithm

(TWTT, 15-04-0050-00-003a) o PHY resources are described in 1.7 of 15-04-0493-00-003a

minimum resolution in the order of 60cm optional capabilities in the order of 7cm

o The corresponding MAC resources are beyond the scope of TG3a. see 15-04-0573-00-004a-two-way-time-transfer-based ranging.ppt for an

overview, as contributed to TG4a ranging subcommitteeo Applications and 2-3 dimensional location awareness are above the MAC.

see 15-04-0300-00-004a-ranging-rf-signature-and-adaptability.doc The MB-UWB PHY ranging support is only a part of location awareness.

o 802.15 TG3a has seen very little location awareness work.o 802.15 TG4a is actively studying location awareness

see 15-04-0581-05-004a-ranging-subcommittee-reporto Their consensus: location awareness transcends the PHY.

It is unrealistic for the PHY layer to construct or maintain 2 or 3 dimensional models of a device location.

Ranging and/or angle-of-arrival measurements are within the scope of the PHY (and MAC).

o They have studied several algorithms; no choice have been made. TWTT uses minimal additional hardware Angle-of-arrival requires multiple antennas

Questions were answered by Joe Decuir on:

Precise ranging – resolving multipatho What constitutes acceptable

Detail on implementation



November 2004 IEEE P802.15-04/0638r4

TUESDAY, 16 NOVEMBER 2004

Session 3

The TG chairman, Bob Heile, called the session to order at 1:30 PM

Joy Kelly showed the outline (slide 2) in document 15-04-0641-01-003a. Joy also told us that questions on the next four short presentations will be held after they are complete, or following the final presentation by Jim Lansford.

David Leeper presented the following points on coexistence document 15-04-0641-01-003a:

I suggest that the Merged Proposal #1 and Merged Proposal #2 merge and become Merged Proposal #3

o Customers have indicated preference for a single PHY standard The clock frequencies and convolutional coder do not support a common signaling

mode.o CSM is not required for MB-OFDM and will add unnecessary cost and

complexity. Clock frequencies & conv coder do not need to support CSM I believe the commons signaling mode is a way of providing interoperability and

coexistence with other UWB deviceso CSM is not required for MB-OFDM and will add unnecessary cost and

complexity. Clock frequencies & conv coder do not need to support CSM Merged Proposal @2 includes provision for a base signaling mord that would allow

multiple PHYs to coexist. In order for me to vote yes on Merged Proposal #1, there must be some type of coexistence mechanism

o CSM is not required for MB-OFDM and will add unnecessary cost and complexity. Clock frequencies & conv coder do not need to support CSM

Charles Razzell presented the following points on Multipath Performance document 15-04-0641-01-003a:

No Vote comments were:1. The performance in range and survivability even in moderate multipath is absolutely

dismal.2. Parallel and serial transport of the same data rate in the same bandwidth can be equally

efficient against white noise, but the performance with multipath is materially weaker. With direct-sequence spreading, the difference is even greater for multipath interference.

3. A single carrier system with “rake” receiver processing will receive and process more power from combined propagation paths than is possible with N multiple parallel paths each carrying 1/N of the message load (before considering the benefits spectrum


November 2004 IEEE P802.15-04/0638r4

spreading).4. The [direct sequence] spreading causes the multipath to appear as an interference signal

in particular chips. Errors in some individual chips reduces the power sum or Boolean sum relative to no errors, but does not prevent successful evaluation of the data value carried by that sequence. This tolerance for chip errors is a property not found in OFDM which attempts to get this benefit with FEC. Some fraction of corrupted packets might be saved by FEC, but this will be for those packets with a small number of errors.

5. With MB-OFDM, there will be coverage holes where cancellation fades have occurred, and these will no be helped by more power or better error correction. As a rough estimate based on tests at 5 GHz, there may be 5% of locations where a satisfactory decoding cannot be achieved. At such holes, moving the antenna location a small distance may cause satisfactory signal to reappear.

6. The recent changes to the proposal to map data bits on the guard tones have shown that adding more diversity to the bit-tone mapping could help to improve the poor multipath performance of MB-OFDM. Please come up with a way that can add more diversity to these mappings (especially at higher rates, > 200 Mps) in order to compensate for the degraded performance caused by the Rayleigh-distributed multipath fading. Since the 6 dB degradation (@480 Mbps) identified in various other document has been improved by these recent modifications, please derive the new amount of degradation (e.g. 5 dB?) based on the new mappings for the various data rates proposed.

Replies are: System performance has been compared since March 2003 in standardized channel

models CM1-4 MB-OFDM has consistently performed well even in the most severe channel models The results speak for themselves: link distance at 110 and 200 Mbps is hardly

impacted by multipath So, why the counter claims?

o Frequency diversity is not inherent in OFDMo If all available sub-carriers are used to transmit independent information

(without redundancy), each bit of information is subject to Rayleigh-distributed narrow-band fading

o In order to overcome this frequency-domain spreading is needed, which usually implies some redundancy

Why is this not a big issue?o Frequency domain spreading in MB-OFDM is provided by a mixture of

repetition coding and convolutional codingo Even at 480Mbps (the worst case), sufficient spreading gain is available to

obtain 3m link distances in NLOS channels.o At 110Mbps, the scope for spreading has dramatically improved to

approximately 6, partitioned as a factor 3 for FEC and 2 for repetition coding.


November 2004 IEEE P802.15-04/0638r4

Joy Kelly presented the following points on Complexity / Power Consumption / Scalabilitydocument 15-04-0641-01-003a:

FFT vs. Direct Linear Convolutiono Since the UWB channel is highly dispersive, efficient reception requires

coherently combining signal energy received at different times.o This naturally leads to a RAKE or linear FIR filter structure in receiverso It has been known since ~1966 that high speed convolution and correlation is

best performed using FFT/IFFT methods. OFDM makes very efficient use of transforms:

o No overlap and save overheads incurred in the size of required FFTo Only one FFT block is used whether transmitting or receiving (don’t need two

transforms active simultaneously) FFT makes a highly efficient energy collection engine at the heart of the MBOA

proposal XSI: Multi-path Energy Capture

o Need about 12 RAKE fingers in CM4 and 6 RAKE fingers in CM3 for < 3 dB energy loss degradation.

o Further performance loss can be expected due to inter-chip interference, when a sparse RAKE is used

FFT Complexity (Philips’ Estimates)o MBOA OFDM can be achieved at very modest gate counts for the FFT core.

Collated Complexity Estimateso Based on information in P802.15-03/213r0 and P802.15-03/209r3o Multiple companies have studied the complexity of the FFT and Viterbi cores

dimensioned for the MBOA PHY. All results point to feasible and economic implementation in current CMOS processes.

802.11a vs. MB-OFDM complexity comparisono Approach taken:

Start with publicly available 802.11a implementation area estimates Scale these numbers for CMOS process/clock rate/data rate etc.

variationso Key points:

4 bit ADC vs. 10 bit ADC for 802.11a based on QPSK vs. 64-QAM, and other factors. This results in a scale factor of 40% for the signal processing area (assumed 60% of PHY) and no reduction for the bit processing area.

132 MHz BB clock rate vs. 40MHz for 802.11a. This results in a scale factor of 40/132.

o Summary of BB die area comparison results: MB-OFDM PHY silicon area for 110 Mbps solution Approx 86% of the area of the 802.11a PHY


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Calibration point: expected area of 802.11a PHY in 90nm is 2.6 mm2 MB-OFDM vs. IEEE 802.11a power consumption comparison

o There are two significant components that differentiate the power consumption MB-OFDM versus IEEE 802.11a:

o * Power consumption number scaled based on Intel ADC: 5-bit, 520 MHz (linear scaling for frequency, doubling of power for every bit).

oo MB-OFDM consumes 500 mW less at TX and at least 110 mW less at the

receiver analog front-end when compared to IEEE 802.11a. Scalability

o Data rate scaling: Data rates from 55 Mb/s to 480 Mb/s has been defined in the current

proposal. Higher data rates are possible with higher order modulation and/or increased FFT size.

o Power scaling: Implementers have the option to trade power consumption for range

and information data rate.o Complexity scaling:

Digital section will scale with future CMOS process improvements. Implementers can trade-off complexity for performance.

o In a time-spreading scheme the same information is repeated during two symbol durations for data rates of 55 Mbps, 110 Mbps and 200 Mbps.

o Power savings can be obtained by turning OFF the receiver during the time repeated symbols at the expense of system performance.

Majority of the digital section (except the Viterbi decoder) operates for only 50% of the time.

Some of the analog components (LNA, mixer and ADC) can be switched off for a portion of the OFF time. Settling/transition time is approx. 70 ns for ramp down and ramp up of LNA, mixer, and ADC in a 130 nm process Þ expected off time is approx. 172.5 ns (27.6% of 625 ns).

3 dB penalty in performance due to not collecting the energy from both of the time-repeated symbols.

Complexity Scaling o For 110 Mb/s, the MB-OFDM system has a 90% link success probability

distance in excess of 10 meters in all multi-path environments Þ an excess margin of 3 dB for the 55 Mb/s mode.

o Can reduce both the analog and digital complexity/power consumption by reducing the bit precision:

Ex: reducing ADC precision from 4 bits ® 3 bits. Ex: reducing internal FFT precision (reducing the bit-precision of a

multiplier by 30% results in a complexity/power consumption savings of 50%).


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Conclusions on Scalability/Complexityo The “heart” of the Multiband OFDM proposal is an extremely efficient method

of (de-)convolution based on the FFTo The FFT core is likely to require ~64k gates or less at quite modest clock

speeds, according to multiple independent studies.o Studies also showed that the Viterbi core for 480 Mbps is feasible in 75-100k

gates at the same clock speeds (~132MHz).o These gate counts should be considered in the context of the overall system

solution including hardware assisted MAC.o Overall, the FFT gains us excellent, robust performance while remaining very

economic to implement.o Several options are open to implementers to further scale complexity and

power consumption in exchange for performance.

Jim Lansford presented the following points on Time-To-Market from document 15-04-0641-01-003a:

No Vote Comments on: Time-to-Market1. The earliest availability of silicon for this proposal is 2005. An alternative proposal has

ICs available today, which have the ability to be adapted to the precise protocols laid down by the standard, within a very short time of the standard being issued.

2. The DSUWB solution has been shown to work and is commercially available. I will not vote for Merge Proposal #1 unless it can be demonstrated, with real silicon, that it meets the PAR.

3. At least one competing standard has recently geared up it process and is threatening to snatch away a sizeable chunk from this standard’s targeted market. MB-OFDM projects its chipset availability in 2005 (at the earliest). Its counterpart has already cranked out silicon out of the development cycle.

4. It would be interesting to see some, ANY, working hardware demonstrating feasibility of the solution -- even a breadboard, because at this late date I can no longer accept PowerPoint Engineering.

Reply:

TTM difference between proposals is months, not years. MB-OFDM chipsets operating at 480Mb/s have been demonstrated over the air, so

in some ways, MB-OFDM is ahead of DS-UWB, not behind MB-OFDM silicon will be available in the market before a draft could complete the

balloting process Demonstration silicon is available now Early products will be available in months History shows early chipsets have to be re-spun for standards compliance anyway

The earliest availability of silicon for this proposal is 2005. An alternative proposal has ICs available today, which have the ability to be adapted to the precise protocols laid down by the standard, within a very short time of the standard being issued.


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The time difference in availability of silicon is much smaller than has been stated by MBOA opponents. Commercial availability of chipsets will differ only by a few months, not years. MB-OFDM chipsets will be in the market well before the draft specification could be completed. Note that the IEEE802-SEC has taken the position of being against companies releasing chipsets and calling them "pre-compliant" when a standard has not completed letter ballot and sponsor ballot.

The DSUWB solution has been shown to work and is commercially available. I will not vote for Merge Proposal #1 unless it can be demonstrated, with real silicon, that it meets the PAR.

At least one MB-OFDM company has demonstrated MB-OFDM proposal compliant silicon operating at 480Mb/s over the air. This chipset meets the PAR for 200Mb/s operation, unlike the demonstrated DS-UWB product. May we count on you switching your vote?

At least one competing standard has recently geared up it process and is threatening to snatch away a sizeable chunk from this standard’s targeted market. MB-OFDM projects its chipset availability in 2005 (at the earliest). Its counterpart has already cranked out silicon out of the development cycle.

Again, the time difference in availability of silicon is much smaller than has been stated by MBOA opponents. Commercial availability of chipsets will differ only by a few months, not years. MB-OFDM chipsets will be in the market well before the draft specification could be completed.

It would be interesting to see some, ANY, working hardware demonstrating feasibility of the solution -- even a breadboard, because at this late date I can no longer accept PowerPoint Engineering.

We agree. Several MB-OFDM companies now have working silicon. As mentioned in a previous response, working silicon operating over the air at 480Mb/s has been demonstrated which meets the PAR. We are awaiting something other than Powerpoint for a DS-UWB demonstration

Jim then explained what was successful in 802.11b, etc. Home RF proprietary phy and the problems associated. He then asked all to vote for final confirmation tomorrow morning so to eliminate another groundhog day.

The following points were asked and answered on the previous four presentations:

PAR – 110Mbs – 480Mbs FFT and Viterbi power and gates Home RF reference proprietary phy FFT crossover point of complexity Scalability and complexity– low rate comparison and growth to 480Mbs Pictures of Phy and MAC on slide 97 document 15-04-0641-01-003a Reference to actual MBOFDM radios at IDF Side 80 document 15-04-0641-01-003a - multipath performance Averaging window of 1ms for power density per FCC requirement


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Slide 56 document 15-04-0641-01-003a Peak Power Compliance Slide 90 document 15-04-0641-01-003a Power Scaling – repeated data in two bands

back to back – frequency diversity – range by turning receiver off Slide 89 document 15-04-0641-01-003a Scalability – quantitative understanding

o Viterbi power requirementso Wider bandwidtho Modulationo OFDM Historyo Single carrier vs. Multiple carrier – each has advantages and disadvantageso FFT doesn’t change going to next level, but viterbi changes

The session recessed at 2:42PM

WEDNESDAY, 17 NOVEMBER 2004

Session 4

The TG chairman, Bob Heile, called the session to order at 8:00 AM

We immediately began the special order of the day the second confirmation voting. Vote needs to


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be Y (Yes)or N (No) for confirmation of proposal 1 document 15-04-0493-01-003a.

The result was: Yes 83 ; No 80 ; Abstain 1

Chair stated that we are reset to level 4 and asked for contributions. A coin toss decided that DS-UWB goes first. To allow the group to prepare the chair said we will recess until 9:00 AM

The session recessed at 8:31 AM

Session 5

The TG chairman, Bob Heile, called the session to order at 9:00 AM

The first presentation of the morning was given by Matt Welborn on DS-UWB Proposal Update document 15-04-0140-10-003a

The topics covered were:

Outline• Merger #2 Proposal Overview • Scalability• High rate simulation results• Compromise proposal for a TG3a PHY

Key Features of DS-UWB• Based on true Ultra-wideband principles

– Large fractional bandwidth signals in two different bands– Benefits from low fading due to wide bandwidth (>1.5 GHz)

• An excellent combination of high performance and low complexity for WPAN applications

– Support scalability to ultra-low power operation for short range (1-2 m) very high rates using low-complexity or no coding

– Performance exceeds the Selection Criteria in all aspect– Better performance and lower power than any other proposal considered by TG3a

DS-UWB Operating Bands• Each piconet operates in one of two bands

– Low band (below U-NII, 3.1 to 4.9 GHz) – Required to implement– High band (optional, above U-NII, 6.2 to 9.7 GHz) – Optional

• Different “personalities”: propagation & bandwidth• Both have ~ 50% fractional bandwidth

DS-UWB Support for Multiple Piconets• Each piconet operates in one of two bands• Each band supports up to 6 different piconets• Piconet separation through low cross-correlation signals


November 2004 IEEE P802.15-04/0638r4

– Piconet chip rates are offset by ~1% (13 MHz) for each piconet– Piconets use different code word sets

Data Rates Supported by DS-UWBData Rate FEC Rate Code Length Symbol Rate28 Mbps ½ 24 55 MHz55 Mbps ½ 12 110 MHz110 Mbps ½ 6 220 MHz220 Mbps ½ 3 440 MHz500 Mbps ¾ 2 660 MHz660 Mbps 1 2 660 MHz660 Mbps ½ 1 1320 MHz1000 Mbps ¾ 1 1320 MHz1320 Mbps 1 1 1320 MHzSimilar Modes defined for high band

Range for 110 and 220 MbpsRange for 500 and 660 MbpsUltra High RatesScalability

• Implementation complexity versus performance• Higher frequency band for higher rate applications• Baseline devices support 110-200+ Mbps operation

• MB-OFDM device• Reasonable performance in CM1-CM4 channels• Complexity/power consumption as reported by MB-OFDM team

• DS-UWB device• Equal or better performance than MB-OFDM in essentially every case • Lower complexity than MB-OFDM receiver

• What about:• Scalability to higher data rate applications• Scalability to low power applications• Scalability to different multipath conditions

High Data Rate Applications• Critical for cable replacement applications such as wireless USB (480 Mbps) and IEEE

1394 (400 Mbps)• High rate device supporting 480+ Mbps

– DS-UWB device uses shorter codes (L=2, symbol rate 660 MHz)• Uses same ADC rate & bit width (3 bits) and rake tap bit widths• Rake: use fewer taps at a higher rate or same taps with extra gates• Viterbi decoder complexity is ~2x the baseline k=6 decoder• Can operate at 660 Mbps without Viterbi decoder for super low power

– MB-OFDM device


November 2004 IEEE P802.15-04/0638r4

• 5-bit ADCs required for operation at 480 Mbps • Increased internal (e.g. FFT, MRC, etc) processing bit widths• Viterbi decoder complexity is ~2x the baseline k=7 decoder (~4x k=6)• Increased power consumption for ALL modes (55, 110, 200, etc.) results

when ADC/FFT bit width is increasedLow Power Applications

• Critical for handheld (battery operated) devices that need high rates– Streaming or file transfer applications: memory, media players, etc.– Goal is lowest power consumption and highest possible data rates in order to

minimize session times for file transfers• Proposal support for scaling to lower power applications

– DS-UWB device• Has very simple transmitter implementation, no DAC or IFFT required• Receiver can gracefully trade-off performance for lower complexity• Can operate at 660 Mbps without Viterbi decoder for super low power• Also can scale to data rates of 1000+ Mbps using L=1 (pure BPSK) or 4-

BOK with L=2 at correspondingly shorter ranges (~2 meters)– MB-OFDM device

• Device supporting 480 Mbps has higher complexity & power consumption• MB-OFDM can reduce ADC to 3 bits with corresponding performance loss • It is not clear how to scale MB-OFDM to >480 Mbps without resorting to

higher-order modulation such as 16-QAM or 16-PSK– Would result in significant loss in modulation efficiency and

complexity increaseScalability to Varying Multipath Conditions

• Critical for handheld (battery operated) devices – Support operation in severe channel conditions, but also…– Ability to use less processing (& battery power) in less severe environments

• Multipath conditions determine the processing required for acceptable performance – Collection of time-dispersed signal energy (using either FFT or rake processing)– Forward error correction decoding & Signal equalization

• Poor: receiver always operates using worst-case assumptions for multipath – Performs far more processing than necessary when conditions are less severe – Likely unable to provide low-power operation at high data rates (500-1000+

Mbps) • DS-UWB device

– Energy capture (rake) and equalization are performed at symbol rate – Processing in receiver can be scaled to match existing multipath conditions

• MB-OFDM device– Always requires full FFT computation – regardless of multipath conditions– Channel fading has Rayleigh distribution – even in very short channels– CP length is chosen at design time, fixed at 60 ns, regardless of actual multipath

Simulation Results for the High Band• Each piconet operates in one of two bands


November 2004 IEEE P802.15-04/0638r4

– Low band (below U-NII, 3.1 to 4.9 GHz) – Mandatory– High band (optional, above U-NII, 6.2 to 9.7 GHz) – Optional


What high band performance is expected?• Center frequency is twice as high => lose 6dB.• 2 x Bandwidth => 2 x Total power => gain 3dB• Expect overall loss of 3dB w.r.t. low band in AWGN.• 3dB loss equates to a distance loss factor of √2.• AWGN distance for 220Mbps in low band is 16.5m => 11.7m AWGN in high band.• Although there is a loss of 3dB in AWGN, the loss turns out to be less in Multipath

because of the greater frequency diversity.AWGN range comparisonMultipath range comparisonA Framework for Compromise

• A Base Mode (BM) common to all 15.3a devices• Minimal impact on native MB-OFDM or DS-UWB piconet performance• Minimal complexity increase over baseline MB-OFDM-only or DS-UWB-only

implementations• Advantages

– Moving the TG3a process to completion– Mechanism to avoid inter-PHY interference when these high rate UWB PHYs

exist in the marketplace– Potential for interoperation at higher data rates

Impact on MB-OFDM Performance of a Base Mode for Coordination• Multiple piconet modes are proposed to control impact on MB-OFDM or DS-UWB

piconet throughput– More details available in 15-04-0478-r1

• Native MB-OFDM mode for piconets enables full MB-OFDM performance without compromise

– Beacons and control signaling uses MB-OFDM– Impact of BM signaling is carefully limited & controlled

• Less than 1% impact on capacity from BM beaconing• Association and scheduling policies left to implementer

• Performance of BM receiver in MB-OFDM device – Does not constrain MB-OFDM device range performance– Does not limit association time or range for MB-OFDM devices

Beacons for an “MB-OFDM Piconet”• MB-OFDM Capable PNC transmits all beacons using MB-OFDM• Performance controlled / impact limited by 1-in-N BM beacon

– One-in-N superframes the PNC also transmits BM beacon to advertise interoperability & support non-MB-OFDM DEVs

– Even if N=1 (I.e. every superframe = worst case) overhead is ~1%Interoperation with a shared Base Mode


November 2004 IEEE P802.15-04/0638r4

What Does CSM Look Like?One of the MB-OFDM bands!Higher Data Rates Possible for CSM

• CSM waveform can provide higher data rates for interoperability– Shorter ranges– Higher rates require complexity than base CSM rate – Some rake or equalizer may be helpful at higher rates

Conclusions: Compromise• A single PHY with multiple modes to provide a complete solution for TG3a

– Base mode required in all devices, used for control signaling– Higher rate mode also required to support 110+ Mbps– Compliant device can implement either DS-UWB or MB-OFDM (or both)

• Advantage relative to uncoordinated DS-UWB and MB-OFDM deployment is usability– Mechanism to avoid inter-PHY interference– Potential for higher rate interoperation

• Increases options for innovation and regulatory flexibility to better address all applications and markets

– Smaller spectral footprint than either DS-UWB or MB-OFDMConclusions: DS-UWB

• DS-UWB has excellent performance in all multipath conditions• Scalability to ultra-high data rates of 1 Gbps • High performance / low complexity implementation supports all WPAN applications

– Mobile and handheld device applications– WPAN & multimedia applications

• Support for CSM as a compromise (Optional)

Question topics and answered by Matt were:

Joe Decuir had a friendly suggestion about ranging in DS-UWB, that the next update should include the whole text on ranging. Matt said check 15-04-0137-03-003a

Hirohisa Yamaguchi asked about the DPSK and the spreading code – using two different bit streams aligning with each other using up the whole bandwidth. Synchronizing at the receiver is impossible.

Anuj Batra slide nine in document 15-04-0140-10-003a Ultra High Rates why is this valuable if it doesn’t meet the requirements? Does work 85% of the time. This provides information purpose.

Dave Leeper asked about UWB and the new emerging systems. Spectral flexibiulty is transparent. You can use baseband signal generation using FFT or D/A converter.

Dave Brenner asked about a clarification about a single standard. Are we fracturing the market? Getting the IEEE process to get coexistence is important.

The chair said we are in recess until 1:30 PM

The session recessed at 10:05 AM


November 2004 IEEE P802.15-04/0638r4

Session 6


The first presentation of the afternoon was given by John Terry on Multiband OFDM Update and Overview Update document 15-04-0518-02-003a

Points covered were:

Introduction• The purpose of this document is to provide an overview of MultiBand OFDM (doc. 15-

04-0493) including– Technical characteristics and advantages– Identification of key supporters– References to supporting material– That this proposal meets the TG3a PAR.

Proposal Overview• The MultiBand OFDM proposal:

– Is based on proven OFDM technology• Used in IEEE 802.11a and 802.11g

– Achieves data rates of 53.3 to 480 Mbps– Support for 4 to 16 simultaneous piconets – Spectrum easily sculpted for international regulatory domain compliance– Is easily extensible for future range/rate improvements

Frame Format

• PLCP Preamble– Deterministic sequence– Allows packet detect and piconet identification

• PLCP Header– Encoded at 53.3 Mbps– Contains reserved bits for future extensions

• Payload


PLCP PreamblePHY

HeaderMAC

HeaderHCS

TailBits

TailBits

PadBits

Frame PayloadVariable Length: 0 4095 bytes

PadBits

TailBits

FCS

53.3 Mb/s

PLCP Header

53.3*, 80, 110*, 160, 200*, 320, 400, 480 Mb/s

November 2004 IEEE P802.15-04/0638r4

– Coded at 53.3 to 480 Mbps• Each frame contains multiple OFDM symbols

Encoder – see document 15-04-0518-02-003a slide 5

Packet at Baseband Packet at Baseband• Each OFDM symbol is 312.5 ns long containing:

- 60.6 ns null cyclic prefix - 242.4 ns of data transmission - 9.5 ns guard

• Number of OFDM Symbols: - Packet sync: 21 - Frame sync: 3 - Channel estimation: 6 - PLCP header: 12 - Payload: Variable (54 at left)

SpectrumDAC converter rate = 528 MHz

Tone width = 4.125 MHz

Instantaneous Bandwidth ≈ 123 * 4.125 MHz = 507 MHzAs characteristic of OFDM systems, signal roll-off is sharp yielding excellent adjacent channel interference characteristics

Band Groups• Spectrum is divided into 14 bands• Bands are spaced at 528 MHz• Five band groups are defined• Enables structured expansion• Each Time Frequency Code (TFC) corresponds to a Logic Channel• Logical Channels enable Simultaneously Operating Piconets (SOPS)• Four SOPS are enabled on Band Group1

AWGN Performance see slide 9 document 15-04-0518-02-003a

Enhancements to Proposal• Changes made since July 2004:

– 55 Mbps changed to 53 1/3 Mbps– Lower PAR Channel Estimation sequence included– Mapping of data tones onto guard tones


November 2004 IEEE P802.15-04/0638r4

Features• Regulatory

– Meets FCC requirement for 500 MHz minimum bandwidth, without adding noise to guard tones

– Maximally flexible for regulatory expansion due spectral sculpting capability• Robustness

– Time Frequency Coding provides frequency diversity gain and robustness to interference

System Performance (3-band)• The distance at which the Multi-band OFDM system can achieve a PER of 8% for a 90%

link success probability is tabulated below:• Includes losses due to front-end filtering, clipping at the DAC, ADC degradation, multi-

path degradation, channel estimation, carrier tracking, packet acquisition, no attenuation on the guard tones, etc.

Signal Robustness/Coexistence• Assumption: Received signal is 6 dB above sensitivity.• Values listed below are the required distance or power level needed to obtain a PER £ 8%

for a 1024 byte packet at 110 Mb/s and operating in Band Group #1.• Coexistence with IEEE 802.11b and Bluetooth is relatively straightforward because they

are out-of-band.• Multi-band OFDM is also coexistence friendly with both GSM and WCDMA.

– MB-OFDM has the ability to tightly control OOB emissions.

PHY-SAP Throughput• Assumptions:

– MPDU (MAC frame body + FCS) length is 1024 bytes.– SIFS = 10 ms.– MIFS = 2 ms.

• Assumptions:– MPDU (MAC frame body + FCS) length is 4024 bytes.

PHY Complexity• Unit manufacturing cost (selected information):

– Process: CMOS 90 nm technology node in 2005.– CMOS 90 nm production will be available from all major SC foundries by early

2004.• Die size for the PHY (RF+baseband) operating in Band Group #1:• Active CMOS power consumption for the PHY (RF+baseband) operating in Band Group

#1 :

Support of range measurements


November 2004 IEEE P802.15-04/0638r4

• Location awareness is optional in TG3a– Ranging is one-dimensional location awareness

• The MB-UWB PHY supports 'Time-of-Arrival' ranging– Two Way Time Transfer, from 15-04-0050-00-003a– Similar to 'DTOA' described in DS-UWB (8.17/030154r3)– see 2/15-04-0581-05-004a for TOA ranging description

• PHY resources are described in section 1.7 of 15-04-0493-00-003a– add a fast timer– minimum resolution of ~ 60cm (528 MHz clock)– crystal tolerances support ~ 30 cm (1056 MHz clock)– optional support to ~ 7 cm (4224 MHz clock)

MB-OFDM Support• MultiBand OFDM has an unprecedented level of support and serves the needs of:

– Major Personal Computer manufacturers– Major Mobile Phone manufacturers– Major Consumer Electronics manufacturers– Major Software companies– Component manufacturers– Test equipment manufacturers

MB-OFDM Advantages MB-OFDM

Piconets Supported 16Extendable to high rate/longer range

Yes, via industry standard techniques

Coding 64-State Binary Convolutional CodeRegulatory Flexibility HighClear Channel Assessment Robust, Preamble-based and

Non-preamble-based MechanismMultipath Immunity Inherent from OFDMSpectral Sculpting üü

Industry Support üüü


November 2004 IEEE P802.15-04/0638r4

WiMedia Support ü

Exploits Moore’s Law üü

Previous Submissions 1. MB-OFDM Update and Overview, Matthew B. Shoemake (WiQuest), doc. 15-04-05182. MB-OFDM Specification, Anuj Batra (Texas Instruments), et al., doc. 15-04-493 3. Market Needs for a High-Speed WPAN Specification, Robert Huang (Sony) and Mark

Fidler (Hewlett Packard), doc. 15-04-04104. MB-OFDM for Mobile Handhelds, Pekka A. Ranta (Nokia), doc. 15-04-4325. In-band Interference Properties of MB-OFDM, Charles Razzell (Philips), doc. 15-04-04126. Spectral Sculpting and Future-Ready UWB, David Leeper (Intel), Hirohisa Yamaguchi

(TI), et al., doc. 15-04-04257. CCA Algorithm Proposal for MB-OFDM, Charles Razzell, doc. 15-04-04138. What is Fundamental?, Anuj Batra, et al., doc. 15-04-4309. Time to market for MB-OFDM, Roberto Aiello (Staccato), Eric Broockman (Alereon)

and David Yaish (Wisair), doc. 15-04-432

Select References15-03-0343, MultiBand OFDM September 2003 presentation, Anuj Batra15-03-0449, MultiBand OFDM Physical Layer Presentation, Roberto Aiello and Anand Dabak15-04-0010, MultiBand OFDM January 2004 Presentation, Roberto Aiello, Gadi Shor and Naiel Askar15-04-0013, C-Band Satellite Interference Measurements TDK RF Test Range, Evan Green, Gerald Rogerson and Bud Nation15-04-0017, Coexistence MultiBand OFDM and IEEE 802.11a Interference Measurements, Dave Magee, Mike DiRenzo, Jaiganesh Balakrishnan, Anuj Batra15-04-0018, Video of MB-OFDM, DS-UWB and AWGN Interference Test, Pat Carson and Evan Green

Summary• Inherent Multipath Capture and Immunity• High Performance Error Control• Range/rate extendable• Spectral Sculpting for Global Expandability• Superior channelization• Low Cost and Power Consumption

The MB-OFDM proposal meets or exceeds PAR requirements and selection criteria.

Question were raised and answered on the following

Channel selection robustness – used 802.11n models to compare


http://www.wisair.com/

http://www.alereon.com/

http://www.staccatocommunications.com/

http://www.philips.com/

http://www.nokia.com/

http://www.hp.com/

http://www.sony.com/

http://www.ti.com/

http://www.wiquest.com/

November 2004 IEEE P802.15-04/0638r4

Proposal is compliant with FCC UWB rules – what is the fallback plan?o Waiver asks that certain tests be removed as they do not apply.

0.0m at 90% - means that certain situations cause high error rate Link budget – transmit power calculations – analysis shows ripple and is the same FCC approved? Density masks. OFDM peak meets FCC requirements. MB-OFDM

waiver asks that test measurement procedures e changed. Power consumption for 480Mbps is not as high as implied Bit width changes – don’t they change power consumption – viterbi Waiver documents put together by John Barr – he wants to present later this afternoon –

end result is not about spectrum mask, but what you drive at what time. Frequency hopping causes unique problems, gated signal. If waiver is denied will your proposal still meet the PAR? There is an ambiguity in the tests and a waiver was requested. Frequency hopping restriction does not apply, nor does the gating restriction. Analysis and tests at the FCC show that MB-OFDM does not have more power than any other solution.

Slide 17 document 15-04-0518-02-003a - Are these companies going to use 802.15.3 MAC? These companies support the phy.

Complexity of the FFT. – OFDM allows the use of shorter prefix if signal channel is short. Assuming that the channel is short is not a good solution and OFDM solves this problem It makes it a one time equalization.

Slide 5 document 15-04-0518-02-003a – Is there an implied filter? It depends on the final application.

What about the ripple in the link budget. Will the data be changed? The data being shown is data from prototypes. The comparisons are the same.

Range measurements – section 1.7 of 15-04-0493-00-003a reference – how to get to 7cm?

The chair said that we will now, vote on the down selection 1= MB-OFDM ; 2= DS-UWB

David Brenner requested that the chair allow a floor motion to consider open roll call voting for the down select and confirmation votes. He expressed his concern given the scrutiny and consideration for entity voting. The chair stopped the proposal before it could go to the floor, stating that he was "required by the EC and SA to conduct anonymous voting" until further notice. The chair also said he will not change this unless told to do so by IEEE. Bob Huang requested that the Secretary note Bob's comments in the minutes.

The result of the down-select was: 84 for MB-OFDM; 89 for DS-UWB; 1 ABSTAIN

Immediately following a confirmation vote for DS-UWB was taken.

The chair said we will recess until 4:00 PM today and begin with contribution presentations.


November 2004 IEEE P802.15-04/0638r4


Session 7


The result of the confirmation vote Y (Yes) 88; N (No) 78; and 1 ABSTAIN

The chair said he wanted no vote comments in by mid December. A file will be setup on the server and Rick Alfin will notify how to email you comment to it.

Matt Welborn then gave his presentation on Extended Common Signaling Mode document 15-04-0341-02-003a. The following points were covered:

Background• Initial TG3a discussions on a “Common Signaling Mode” (CSM) began some months ago

– A few ad hoc meetings during January TG3a Interim– Ad hoc meeting in February– Several presentations in March Plenary

• Other attempts at compromise to allow forward progress in TG3a not successful– ~50/50 split in TG3a voter support for two PHY proposals– Little support for two optional independent PHYs

• Can we re-examine some of the ideas for a single multi-mode UWB PHY as a path for progress?

A Framework for Compromise• A Base Mode (BM) common to all 15.3a devices

– Higher rate modes also required to support 110+ Mbps (PAR)• Minimal impact on native MB-OFDM or DS-UWB piconet performance• Minimal complexity increase over baseline MB-OFDM-only or DS-UWB-only

implementations• All devices work through the same 802.15.3 MAC

– User/device only sees common MAC interface – Hides the actual PHY waveform in use– Effectively only one PHY – with multiple modes

• Advantages– Moving the TG3a process to completion– Mechanism to avoid inter-PHY interference when these high rate UWB PHYs

exist in the marketplace– Potential for interoperation at higher data rates

Interoperation with a shared Base Mode see slide 4 document 15-04-0341-02-003a.


November 2004 IEEE P802.15-04/0638r4

Issues & Solutions for CSM• Common frequency band

– Solution: Use band that overlays MB-OFDM Band #2 – Passed by MB-OFDM FE with hopping stopped

• Initial CSM rates were too low for some applications– Add extensions to higher rates (at slightly reduced ranges)– As high as 110-220 Mbps for interoperability, depending on desired level of

receiver complexity• Impact on MB-OFDM piconet performance (throughput)

– Native mode piconets with less than 1% impact on capacity• Common FEC

– Solution: Each receiver uses native FEC (e.g. k=6/7 Viterbi)– Every transmitter can encode for both codes – low complexity

Impact on MB-OFDM Complexity of a Specific Base Mode – the CSM• The CSM proposal is one specific example of a possible shared Base Mode

– Others are possible– Common mode could be null set or some optional mode

• Very little change to the MB-OFDM receiver– Negligible change to RF front-end– No requirement to support 2 convolutional codes

• No additional Viterbi decoder required• Non-directed CSM frames can use multiple codes

– Low complexity for multipath mitigation• No requirement to add an equalizer• No requirement for rake• CSM receiver performance is acceptable without either

What Does CSM Look Like? One of the MB-OFDM bands!

Interoperability Signal Details• MB-OFDM band 2 center frequency for common signaling band

– Centered at 3976 MHz with approximately 500 MHz bandwidth– BPSK chip rate easily derived from carrier: chip = carrier frequency / 9– Frequency synthesis circuitry already present in MB-OFDM radio

• 500 MHz BPSK is similar to original “pulsed-multiband” signals– Proposed by several companies in response to TG3a CFP– Better energy collection (fewer rake fingers) than wideband DS-UWB– More moderate fading effects than for MB-OFDM (needs less margin)

• Relatively long symbol intervals (10-55 ns) avoids/minimizes ISI– Equalization is relatively simple in multipath channels– Not necessary for lowest (default) CSM control/beacon rates

• Use different CSM spreading codes for each piconet – Each DEV can differentiate beacons of different piconets


November 2004 IEEE P802.15-04/0638r4

– Provides processing gain for robust performance: signal BW is much greater than data rate

Interoperability Signal Generation• CSM signal could be generated by both MB-OFDM and DS-UWB devices using existing

RF and digital blocks• MB-OFDM device contains a DAC nominally operating at 528 MHz

– A 528 MHz BSPK (3 dB BW) signal is too wide for MB-OFDM band filters– DAC an be driven at slightly lower clock rate to produce a BPSK signal that will

fit the MB-OFDM Tx filter– Result: 500 MHz BPSK signal that DS-UWB device can receive & demodulate

• DS-UWB device contains a pulse generator– Use this to generate a 500 MHz BPSK signal at lower chip rate – This signal would fit MB-OFDM baseband Rx filter and could be demodulated by

the MB-OFDM receiver

Higher Data Rates Possible for CSM• CSM waveform can provide higher data rates for interoperability

– Shorter ranges– Higher rates require complexity than base CSM rate – Some rake or equalizer may be helpful at higher rates

Implementation• Mandatory/optional modes determined by TG3a to meet performance & complexity goals

for applications• Implementations do not need “optimal” receivers

– Sufficient margins for moderate range interoperability• Shorter codes for higher rates can be based on “sparse” chipping codes (e.g. “1-0-0-0”)

– Eliminate need for transmit power back-off– Peak-to-average still supports low-voltage implementation

• Equalizers desirable at higher CSM rates (>20 Mbps?)– Complexity is very low (a few K-gates), and works great

• Other transceiver blocks (Analog FE, ADC/DAC, Viterbi decoder, digital correlators, etc.) already in radio

Range for CSM modes (90% Outage Ranges)

Range for CSM modes (Mean Ranges)

Impact on MB-OFDM Performance of a Base Mode for Coordination• Multiple piconet modes are proposed to control impact on MB-OFDM or DS-UWB

piconet throughput– More details available in 15-04-0478-r1

• Native MB-OFDM mode for piconets enables full MB-OFDM performance without


November 2004 IEEE P802.15-04/0638r4

compromise– Beacons and control signaling uses MB-OFDM– Impact of BM signaling is carefully limited & controlled

• Less than 1% impact on capacity from BM beaconing• Association and scheduling policies left to implementer

• Performance of BM receiver in MB-OFDM device – Does not constrain MB-OFDM device range performance– Does not limit association time or range for MB-OFDM devices

Beacons for an “MB-OFDM Piconet”

• MB-OFDM Capable PNC transmits all beacons using MB-OFDM• Performance controlled / impact limited by 1-in-N BM beacon

– One-in-N superframes the PNC also transmits BM beacon to advertise interoperability & support non-MB-OFDM DEVs

– Even if N=1 (I.e. every superframe = worst case) overhead is ~1%

Overhead of a Base Mode Beacon for Superframe

• Assume a heavily loaded piconet: 100 information elements in beacon• “Fast” 15.3a beacon overhead with 100 IEs (e.g. CTAs) @ 55 Mbps


BM Beacon + Assoc. CAP

MB-OFDM Beacon1

2

N

N+1

…CTA CTA

CTA CTA

CTA

CTA

CTA

CTA CTA

MB-OFDM Beacon

MB-OFDM Beacon

MB-OFDM Beacon

CTA

Superframe Duration

#

Beacon Preamble SIFS

Beacon Payload

Total Beacon Overhead

Total Superframe Duration (65 ms)

Other Traffic

November 2004 IEEE P802.15-04/0638r4

• (15 us preamble + 107 us payload + 10 us SIFS) / 65 ms = 0.2 % • CSM beacon overhead, assume 100 IEs (e.g. CTAs) @ 9.2 Mbps

• (~50 us preamble + 643 us payload + 10 us SIFS) / 65 ms = 1.1 %• Overhead (as a percent) could be higher for shorter superframe duration – lower

for shorter

Packets For Two-FEC Support

• FEC used in CSM modes to increase robustness– Each device can use native FEC decoder (e.g k=7 or 6)

• For multi-recipient packets (beacons, command frames)– Packets are short, duplicate payload for two FEC types adds little overhead to

piconet• For directed packets (capabilities of other DEV known)

– Packets only contain single payload with appropriate FEC• FEC type(s) & data rate for each field indicated in header fields

Conclusions: Compromise through a Base Mode Approach• A single PHY with multiple modes to provide a complete solution for TG3a

– Base mode required in all devices, used for control signaling– Higher rate mode also required to support 110+ Mbps– Compliant device can implement either DS-UWB or MB-OFDM modes (or both)

• Advantage relative to uncoordinated DS-UWB and MB-OFDM deployment is usability– Mechanism to avoid inter-PHY interference– Potential for higher rate interoperation

• Increases options for innovation and regulatory flexibility to better address all applications and markets

– Smaller spectral footprint than either DS-UWB or MB-OFDM

Questions were raised and answered on the following points: CSM has been several iterations and the new update is only directed at

802.15.3a With respect to Worldwide regulatory, what is the complexity issues for

CSM? Radio astronomy bands, exploratory satellites in Japan, and others mean we would have to reshape the pulse.

A successful CSM solution might be a very good idea. Is this a band aid? Avoidance doesn’t solve the problem. Media access

problem – scheduling for different uses. Slide 10 document 15-04-0341-02-003a – Chipping at a rate of a multiple

of the data rate. Constant interference? Is there degradation of the signal? No simulations have been done that would show the degradation. However the robustness of CSM should not yields such a problem. We need to study this interference closer.


CSM PHY Preamble

Headers

FEC 1 Payload

FEC 2 Payload

November 2004 IEEE P802.15-04/0638r4

Sang-Sung Choi then gave his presentation on Implementation of Viterbi decoder for MB-OFDM System document 15-04-0623-00-003a. The following points were covered:

Introduction MB-OFDM UWB system uses rate 1/3, k=7 convolutional code Information bit rates up to 480Mbps

o Very high speed Viterbi decoder is needed ETRI is developing MB-OFDM UWB chip with 200Mbps data rate Modem architecture based on 4-parallel architecture Viterbi decoder is designed using 2-parallel architecture In this presentation,

o Implementation of Viterbi decoder architecture for mandatory mode

o Simulation results for important parameterso Hardware synthesis resulto Consideration for full rate Viterbi decoder implementation

Viterbi Decoder Target Performance

Viterbi Decoder Requirement

Implemented Architecture Input data for 2-parallel Architecture

o n-th data input Rn(r0, r1, r2 ), (n+1)-th data input Rn+1(r0, r1, r2)o input clock is 132MHz for mandatory mode chip

Full parallel ACS (64 states) o each ACS – radix-4 architecture

Trace back method : depth(L) = 42 Decoded output data

o 2 bits per 132MHz

Input bits decision

Trace-back Depth Simulation

Implementation Result Device : Xilinx x2v6000 ff1152 -5 Constraint : Time constraint 100MHz Logic Utilization:

o Number of Slice Flip Flops : 5,675 out of 67,584 8%o Number of 4 input LUTs : 4,588 out of 67,584 6%

Logic Distribution:


November 2004 IEEE P802.15-04/0638r4

o Number of occupied Slices 5,110 out of 33,792 15%

Total equivalent gate count for design : 87,084 Maximum operation frequency : 92.5MHz

o Mandatory mode chip with 132MHz is possibleo Full rate mode chip with 264MHz is difficult

Critical Path Analysis Post Map timing report Critical path delay time is about 5ns 9 bit adder 2 stage + (4x1 multiplexer) + other delay Less than mandatory mode minimum time(7.58ns) Post Place & Route timing report 2.7 ns (logic) + 7.8 ns (route) + other delay

Implemented Viterbi decoder Performance

Consideration for Full Rate To implement using current architecture

o 9bit Adder 2 + (4x1MUX) is possible in 3.79nso But implementation is difficult due to additional delay

Extend current architecture to 4-parallel (radix-16) architectureo 9bit Adder 2 + (16x1MUX) is possible in 7.58nso Implementation is possibleo Number of adders increase 4 times over that of 2-parallel o Much more complex BM control and other control logico Expect 100% increase in hardware complexity

More Solutiono Bit-level : Input pipeline in feed-back path o Algorithm-level : cascaded feed-forward and backward method, etc.

Conclusion Suggested architecture of Viterbi decoder for MB-OFDM mandatory mode To verify the architecture, hardware design using FPGA is done FPGA synthesis result show mandatory mode chip is possible using current

architecture Estimated gate count of Viterbi decoder is 90K From synthesis result, full rate Viterbi decoder needs 4-parallel architecture

or other algorithms to implement

Question was raised and answered on the following points:


November 2004 IEEE P802.15-04/0638r4

Full range with 2-parallel very difficult and it should go to 4-parallel archetecture Radix 2 viterbi being used.


THURSDAY, 18 NOVEMBER 2004

Session 8


The first presentation of the day was given by Shahriar Emami on Multi-Band OFDM Interference on In-Band QPSK Receivers Revisited, document 15-04-0451-02-003a

Points covered were:Motivation

Goal: To provide additional simulation results for the source of interference in MB-OFDM modulation. Focus is on interference to in-band high data rate wireless systems, particularly TVRO satellite receivers using QPSK modulation.

Note: Multi-band UWB, including MB-OFDM, concentrates its energy in a narrower bandwidth than a comparable DS-UWB system under equal effective isotropic radiated power (EIRP). The filter captured energy is higher.

Approach: Analyze the source of interference from a time and spectrum perspective. Additionally: Clarify initial results of Portland meeting.

Multi-band UWB Power FCC states power spectral density for UWB devices must be -41.3 dBm/MHz in band

between 3.1 and 10.6 GHz. Since multi-band signals hop over a selected band of frequencies, the power spectrum is

scaled by the hop and averaged over the band. The resulting power spectral density is made equal to a system over any arbitrary band.

OFDM and AWGN Subcarriers are orthogonally spaced in frequency. Data modulation on subcarriers randomizes amplitude and phase. Peak-to-average approaches that of AWGN as the number of subcarriers increases, but is

bound to 10 log (N). Energy in time equals energy in spectrum

Spectral densities are inversely proportional to the bandwidth of the signal. OFDM concentrates more of its energy over a narrower spectrum than DS-UWB, hence

higher spectral density.


November 2004 IEEE P802.15-04/0638r4

This is evident at the output of the matched filter with optimum sampling.

OFDM Modeled as Gated AWGNIn doc. 315r0 the MB-OFDM results were with two phenomena captured:

• PSD growth due to equal EIRP• Additional interference due to averaging of EIRP over the hop depth.

We need to equate the PSD so that the averaging of the EIRP produces the actual PSD growth (i.e., we need to make the PSD’s of each interference the same).

Gated AWGN Revisited see slide 12 document 15-04-0451-02-003a

Consider Interference-to-Noise see slide 13 document 15-04-0451-02-003a

BER versus INR for 3 Hops• Lower INR results in less interference, but not zero.• In evaluating INR we cannot assume users are cognizant of regulatory rules.• DS-UWB causes lower interference relative to MB-OFDM when latter is modeled as

gated noise.

Plot of Theoretical Loss for Gated Noise Source• Evaluating:

• Lower INR results in less loss (back-off), but not zero.• Loss is higher for longer hops• DS-UWB is always lower interference relative to an MB-OFDM system.

Filtered MB-OFDM Revisited• For filtered MB-OFDM, it is assumed that the filter rise time is still sufficient to capture

the full interference levels.• Filtering consists of the ideal rejection of subcarriers outside the desired bandwidth.• Energy is made equal over the bandwidth of the filter by scaling the interference using 10

log(M/N) where M is the number of subcarriers captured and N is total number of subcarriers.

Filtered MB-OFDM Results• Ideal filtering implemented: 40 MHz bandwidth corresponds to 8 subcarriers passed, all

others infinitely rejected. • Power scaled so that PSD of MB-OFDM and AWGN are the same.• As Eb/No increases, trend seems to be that SER improves.

Clipped MB-OFDM Results• Clipping level set at 9 dB per the MB-OFDM proposal.


November 2004 IEEE P802.15-04/0638r4

• Clipping has no impact on BER results.• Impulsive characteristic is suppressed, but main contributor is still the bursty nature of the

MB-OFDM interference.

Gated Noise Interference with FEC• Convolutional code, constraint length K = 7 with hard decision, yields about 5 dB coding

gain for all cases. • No interleaving performed.• FEC improves BER performance of all interference.• MB-OFDM as gated noise is still worse interferer.

Impulse Radio Comparisons• Impulse radio modeled as gated AWGN process similar to MB-OFDM.• Pulse width is 2 nsec, corresponding to 500 MHz bandwidth.• EIRP averaged over the hop depth of the gated noise model for MB-OFDM.• Practical PRF range considered.• For very high PRF, impulse radio approaches AWGN.• For lower PRF, SER for impulse radio rises moderately.• Under constraint of identical 500 MHz bandwidth, impulse radio interference is lower

than MB-OFDM modeled by same gated noise process

Conclusions• Ungated OFDM is a more harmful interferer than DS-UWB under equal EIRP constraint

because the energy is concentrated over a narrower bandwidth.• Gated noise model was used to evaluate MB-OFDM interference under equal PSD

constraint. Results show higher interference from gated noise than continuous noise.• Gated noise model was extended to handle interference-to-noise ratios and theoretical loss

difference between systems established for lowest hop depth N = 3.• Filtered MB-OFDM seems to indicate that narrower filtering improves SER performance

slightly. However, results are optimistic as they account for “ideal” filtering.• Results for clipped MB-OFDM show basically no difference when compared to unclipped

MB-OFDM.• All interference sources benefit from FEC, but MB-OFDM is still worse than DS-UWB.• Impulse radio interference is less than that of MB-OFDM when both are modeled as gated

AWGN processes with equal 500 MHz bandwidths and over practical PRF ranges.

Questions and answers were on the following points:

• Un-gated – BW=528 MHz MB-OFDM vs. BW=2 GHz DS-UWB comparisono Should be 2GHz for MB-ODFM

• Stationary signal concept• Gated AWGN – Interference to noise as NS goes to zero (Asymptotic Behavior)• PSD equation P(f) units of watts – equation seems incorrect• How does this relate to the tests and waiver? If in one band interference would be less.


November 2004 IEEE P802.15-04/0638r4

But power should be 3 times. Receiver responds to the interval where you have and the interval where you do not have noise.

• PSD at 528MHz for MB-OFDM – how can it be 5.78 dB higher? Instantaneous vs. averaging when used on DS-UWB -. Pulse radio then produces additional 5 DB over MB-OFDM. PSD should be only be measured over time not instantaneous.

• Comparing PSD should be done while using FCC compliance.

The second presentation of the day was given by Torbjorn Larsson on Impact of MB-OFDM and DS-UWB Interference on C Band Receiversdocument 15-04-0609-03-003a


Motivation and Objective• Motivated by two contributions:

1) 04/0412r0, In-band Interference Properties of MB-OFDM, by C. Razell, Philips2) 04/547r0, Responses to “In-Band Interference Properties of MB-OFDM”, by C.

Corral, G. Rasor, S. Emami, Freescale Semiconductor• The emphasis in the above contributions is on qualitative analysis• In contrast, the approach here is “brute force” simulation• Our hope is that the assumptions made are universal enough to be accaptable to the entire

802.15.3a task group• The author is an independent consultant, not affiliated with any UWB company. This

work was not carried out under any consulting contract

C-Band DTV Systems• The C-band downlink spans 3.7 – 4.2 GHz• C-band antennas are typically 6 – 12 feet in diameter• Based on the DVB-S (Digital Video Broadcasting – Satellite) standard (EN 300 421)• DVB-S was designed for MPEG-2 broadcasting in the Ku-band, but is also used in the C-

band• DVB-S does not specify a unique set of data rates or symbol rates; However…• Typical transponder bandwidth is 36 MHz (33 MHz also used)• Typical symbol rate 27 – 29 Msps• DVB-S2 is the next generation with improved bandwidth efficiency and FEC

Typical C-Band Downlink Channelization• Total of 24 channels• Each polarization has 12 channels• Transponder bandwidth is 36 MHz with a 4 MHz guard band• The center frequencies are separated by 40 MHz• The center frequencies for the two polarizations are offset by 20 MHz• The result is 24 center frequencies separated by 20 MHz


November 2004 IEEE P802.15-04/0638r4

DTV Simulation Model• Excludes Reed-Solomon coding and interleaving

– Impossible to simulate error rates with RS coding– Will probably favor DS-UWB

• Symbol rate: 27 Msps• No quantization (including input to Viterbi decoder)• Ideal pulse shaping/matched filters (0.35 roll-off)• No nonlinarity• No frequency offset• No phase noise• Pre-computed phase error and time offset• Receiver noise figure: 4 dB• Intend to run simulations for all code rates – Results presented only include rate 1/2 and

2/3

MB-OFDM Transmitter Model• Based on the Sep. 2004 release of the MB-OFDM PHY Specifications (P802.15-

04/0493r1)• Complete Matlab implementation of the specifications• System operating in band-hopping mode• Includes (5-bit) DAC and realistic filter characteristics• Spectral pre-shaping to compensate for non-ideal filter characteristics (=> worst-case in

this context!)• Channel number 9 (Band group 1, TFC 1)• Data rate “110” Mbps (106.7 Mbps)

DS-UWB Transmitter Model• Based on the July 2004 release of the DS-UWB PHY specifications (P802.15-04/0137r3)• Complete Matlab implementation of the specifications• No DAC• Ideal RRC pulse shaping filter truncated to 12 chip periods (=> worst-case!)• Channel number 1 (chip rate: 1313 Mcps)• Data rate: “110” Mbps (109.417 Mbps)• BPSK modulation• Spreading code for preamble and header (PAC): -1 0 +1 -1 -1 -1 +1 +1 0 +1 +1 +1 +1 -1

+1 -1 +1 +1 +1 +1 -1 -1 +1• Spreading code for frame body: +1 0 0 0 0 0

Interference Spectra• Transmit power is set so as to push each spectrum as close as possible to the FCC limit

(worst-case condition)• MB-OFDM transmit power is -10.3 dBm• DS-UWB transmit power is -10.8 dBm (data rate dependent)


November 2004 IEEE P802.15-04/0638r4

Interference Spectra – Close Up• Both spectra exhibit substantial variations• Solution: run simulation for multiple DTV center frequencies

Simulated DTV Center Frequencies• Rate 1/2 simulations: 3.8 – 4.3 GHz in steps of 10 MHz

– Arbitrary choice across 500 MHz bandwidth• Rate 2/3 simulations: 3.72 – 4.18 GHz in steps of 20 MHz

– According to channelization plan on slide 6

BER Performance without Interference

Conclusions• For the two simulated cases (rate 1/2 and 2/3), the difference in average BER across the

C-band is 1 dB or less• The difference in worst-case BER is less than 0.5 dB• More general conclusions should be postponed until all code rates have been simulated

Onward…• Run simulations for code rates 3/4, 5/6, 7/8• Run simulations for TFC 3 or 4• Include multipath• Suggestions?

Questions and answers were on the following points:• Signal power 3dB above sensitivity• Interleaving not incorporated and would only result in less interference in the MB-OFDM

simulation.• Multipath added would make it look more like a Gaussian system and MB-OFDM and

DS-UWB would be the same• Rain margin in C-Band• Previous presentation should over 5dB – this one shows less than .5dB – seems like there

is some basic differences.• Feedback is that the 3dB above sensitivity is an excellent choice

The third presentation of the day was given by John Barr on FCC Waiver Request Overview document 15-04-0624-01-003a


Unfolding Event Timeline Process Is Matter Of Public Record


November 2004 IEEE P802.15-04/0638r4

• 26Aug2004 – MBOA SIG Leadership Intel, TI, Staccato, Alereon, and Wisair files petition to for waiver of FCC rules

• 30Aug2004 – FCC Issues DA-04-2793 -- starts proceeding 04-352 – 30-day comment window -- Comments due 29 Sept 2004 followed by– 15-day reply window -- Replies due 14 Oct 2004– All comments and exparte meeting notes are open to public– http://gullfoss2.fcc.gov/prod/ecfs/comsrch_v2.cgi

• Search on proceeding 04-352• MBOA SIG asks for 7 day extension to reply period• Reply period extended to October 21• FCC TAC (technical advisory committee) meeting on October 27

– Meeting is chaired by Ed Thomas, Chief of OET (Office of Engineering and Technology)

• OET is the part of FCC that issued the UWB rules and is considering the waiver request

– Invited talks given by Steven Wood and John McCorkle– Video and slides available on FCC web site

• http://www.fcc.gov/oet/tac/meetings_2004.html• 3Nov04 – TI, Intel, Staccato, and Philips meet with FCC OET• 5Nov04 – Freescale meets with FCC OET

MBOA SIG Waiver Purpose“Based on these test results and he analysis which follows, MBOA-SIG seeks a waiver of the commission’s frequency hopping measurement procedures to allow MB-OFDM systems to be tested for average emissions under normal operating conditions, rather than with band sequencing stopped. Additionally, MBOS-SIG seeks a waiver of the pulse “gating” procedures set forth in Section 15.521(d) of the rules to the extent that these procedures apply to MB-OFDM systems. A waiver of these test procedures will serve the public interest, as it will permit MB-OFDM systems to compete fairly for public acceptance in the market, without increasing the threat of interference from UWB devices.”

The “Stop The Hopping/Gating” Rules DO Apply To MB-OFDM• The FCC’s announcement of proceeding 04-352 proves that the “stop the hopping/gating”

rules DO apply to MB-OFDM– The waiver makes no sense if the “stop the hopping” rules do not apply– The Law of Contradiction does not allow one to say,

“The rules both apply and don’t apply” – You can’t waive nothing (i.e. a non existing rule)

• If the waiver is denied, then– All of the ranges reported by MBOA must be cut in half– Or, all the data rates must be cut in 1/4 for all reported ranges– The MB-OFDM proposal would not meet the 110 Mbps at 10m requirements for

IEEE 802.15.3a (03/030r0)


November 2004 IEEE P802.15-04/0638r4

What Must An Applicant Show - In Order To Obtain A Waiver?“The standards for obtaining a waiver are well established: an applicant must show that a grant of the waiver is in the public interest and does not increase the risk of harmful interference.” (pg 4)

Summary of 29Sept Comments• Against grant of the waiver:

– Motorola, Freescale, C-Band Coalition, Satellite Industry Association, Pulse~LINK, Time Derivative, decaWave, Cingular

• For grant of the waiver:– WiMedia Alliance, Renesas, Time Domain, Philips, Focus, Cetecom, HP, WiLinx,

Alereon, and Harris• Other correspondence:

– MBOA meeting (TI, Intel, Staccato) 23Sept2004– Motorola presentation 28Sept2004

Reasons To Grant The Waiver• No new material except for Philips comments

– All simply reference statements made in the request• Philips comments present an analysis using APDs

(Amplitude Probability Distribution)– Claimed their APD analysis showed susceptibility of victim receivers to MB-

OFDM was acceptable• In reply comments, the APDs analysis was proven flawed

– Counter example proof showed two signals with equal APD yet resulting in significantly different BER impact

– APDs ignore time, which is clearly a factor in susceptibility– Susceptibility conclusions cannot be based on APDs

Reasons To Deny Waiver • Filing misrepresents MBOA - MBOA SIG members not consulted, no advanced notice

that the filing was going to be made (Time Derivative, Pulse~LINK)• Current test procedures DO apply to MB-OFDM (PL)• FCC rules DO apply to MB-OFDM waveform (Cingular, TD)• Waiver increases allowed power which can only increases interference (PL, TD, SIA)

– 6 dB added power in MB-OFDM burst pulses cause a large number of symbol errors in many systems (SIA, CBC)

• Inconsistent with Telecommunications Act of 1996 (PL, TD)– “without regard to any specific technology”– but waiver is special carve out for MBOA– Granting waiver would disadvantage conforming UWB devices that also transmit

in bursts, but cannot average power. (FSL)– Creates unfair advantage FOR MB-OFDM devices (PL, TD)

• Doesn’t meet minimum bandwidth requirement (MOT)• Changes the rules for small companies not aligned with the MBOA-SIG (PL)


November 2004 IEEE P802.15-04/0638r4

• Develop appropriate test procedures (TD)• Insufficient analysis and experience. Current rules still to be proven. Affects of accepting

a waiver has not been adequately analyzed. (FSL, MOT)• Measurement techniques used by the MBOA SIG were flawed. (CBC)• Waiver is wrong mechanism – Needs NPRM rulemaking (Cingular, FSL, MOT)• Waiver is not urgent (FSL, MOT)

– MB-OFDM can be certified under current rules– MBOA spokesman have stated it does not affect marketing plans– MBOA spokesman have stated that products are not likely to hit store shelves for

about 1 year (Steven Wood at FCC TAC meeting, Roberto Aiello at IEEE Berlin)• Waiver is not needed

– Claimed benefits are not the result of hopping (instead are from underlying OFDM)

– MBOA proponents have published alternative approaches that do not hop• Waiver is not (and Petition fails to prove) in the public interest. (Cingular, FSL)• No innovative products or services require the waiver.

– Three of the four technical points claimed to improve performance are wrong.– The fourth claim regarding “flexibility in balancing performance against

implementation complexity” is not clearly explained. (FSL)• Claimed benefits only benefit the manufacturer, not the public• FCC previously stated that changes should be based on commercially available products,

which have not yet been provided. (MOT)• Petitioner has not demonstrated non-interference of commercially available products with

all varieties of the incumbent spectrum users. (MOT)

Summary of October 21 Comments• Against grant of the waiver:

– Freescale, Motorola, decawave• For grant of the waiver:

– MBOA SIG

Additional Issues Raised• Denial of the petition would not disadvantage the manufacturers of MB-OFDM devices as

they would be free to release products under the current rules– CEO of Staccato: “Will not impact product plans” (IEEE 802.15.3a meeting in

Berlin) (15-04-0497-04-003a-berlin-tg3a-meeting-minutes.doc)– Stephen Wood of Intel: “The timeline is not dependent upon the waiver request.

Obviously, there will be performance variation depending on what the outcome is of the waiver.” (answer to questions posed by Ed Thomas at 27Oct04 FCC TAC meeting regarding whether waiver request would affect MBOA member product plans) (http://www.fcc.gov/realaudio/mt102704.ram at 3:27)

• Limited support from MBOA SIG members shows lack of industry support:– MBOA SIG members objected to the waiver petition and only 12 comments

supported the waiver. (MOT)


November 2004 IEEE P802.15-04/0638r4

• Technical support based on APD plots is insufficient to characterize the interference potential of MB-OFDM devices. (FSL)

• No valid test results using commercially available products (MOT)• Possible threat to 4.9 GHz public safety and DSRC services at 5.9 GHz. (FSL)• Close proximity MB-OFDM systems can, via adaptive & ad hock MAC protocols such as

CSMA, operate in a synchronized manner that effectively produces continuous emissions across the entire band that are 5.9 dB above the -41.3 dBm limit – raising potential interference. (FSL)

Conclusion• DS-UWB has already been certified and has no regulatory issues• Hopping rules DO apply to MB-OFDM• If the waiver is denied, then

– All of the ranges reported by MBOA must be cut in half or– All the data rates must be cut in 1/4 for all reported ranges– The MB-OFDM proposal would not meet the required 110 Mbps at 10m– MBOA SIG members will go forward with their product plans outside of the IEEE

• If a waiver is granted– We do not know today exactly what will be granted– Therefore the effect cannot be known today

IEEE 802.15.3a Impact• Products using DS-UWB technology have already been approved by the FCC.• Products using MB-OFDM technology (when available) can be approved by the FCC

using current rules:– MBOA SIG waiver petition admits that the current rules do not allow testing with

band sequencing on• Must turn band sequencing off• Reduces power level by 5.9 dB

– Performance of FCC compliant MB-OFDM devices will not meet IEEE 802.15.3a technical requirements (“A bit rate of at least 110 Mb/s at 10 meters is required at the PHY-SAP.” 03030r0P802-15_TG3a-Technical-Requirements.doc)

– Regulatory approval required (“The alt-PHY standard will comply with necessary geopolitical or regional regulations.” 03030r0P802-15_TG3a-Technical-Requirements.doc)

Two Futures• Waiver Granted

– Incumbent spectrum users file complaints with FCC due to extra interference– No guarantee that the waiver will remain in force after additional review

• Further review under NPRM• Business plans subject to uncertain regulatory approval

– Non-US regulatory bodies avoid FCC rules– Merger #1 and #2 proposals meet 802.15.3a requirements– Fewer UWB devices may get deployed in the market due to regulatory uncertainty

• Waiver Denied


November 2004 IEEE P802.15-04/0638r4

– MBOA SIG members go forward with product plans– Merger #1 proposal does not meet 802.15.3a requirements– Merger #2 proposal does meet 802.15.3a requirements– No regulatory uncertainty– Lots of UWB devices get deployed in the market

IEEE 802.15.3a Call for Proposal• Call For Intent/Call For Proposal (CFI/CFP)• Call For Intent/Call For Proposal was issued on 03Dec02, the latest version which

includes the approved documents from the Jan03 meeting is here or -02/372r8, MS Word (49KB) or via the 21Jan03 2nd notice.

• Call For Intent (CFI) Respondents • Approved, TG3a Technical Requirements -03/030r0, MS Word (1086KB) • Approved, P802.15.3a Alt PHY Selection Criteria -03/031r6, MS Word (381KB) • Approved, TG3a Down Selection Voting Procedure -03/041r7, MS Word (105KB)

TG3a Vote on 03/030r0 (15Jan03)Chairman Bob Heile called the session to order at 3:33 p.m. He said that the business of the session was to conduct two roll call votes—one each on the Technical Requirements document (03/030r0) and Selection Criteria document (03/031r4).

On motion (24 for, 9 against, 6 abstentions), the following text was inserted at the end of the introduction in 03/031: “It is recognized by the committee that the effort required to respond to all of the selection criteria for all three data rates is substantial. To help proposers prioritize their efforts, simulation results for the mandatory minimum rate (>= 110 Mbps) are expected from the proposers during the first round of presentations. Results for the higher mandatory rate of > 200 Mbps and the optional rate of 480 Mbps or more can be provided in subsequent presentations by proposers if desired.”A roll call technical vote was conducted by the vice chairman, Chuck Brabenac, on 03/030r0, with the result 40 for, 3 against, 3 abstentions.See: 03012r6P802-15_TG3a-Ft-Lauderdale-Meeting-Minutes.doc and 03051r0P802-15_TG3a-030r0-Technical-Requirements-Voting-Results.xls

Questions and answers were on the following points:

• Consistent with past experience• Satellite Industry Association, Cingular, and the C-Band Coalition are against UWB

and disagree with any UWB proposals. • For those against the wavier if you take out Satellite Industry Association, Cingular,

and the C-Band Coalition are the rest UWB Forum only? Answer: Yes.• Should we not wait until FCC decides? Will you agree with FCC ruling? Answer: No,

depends which way they rule.


http://grouper.ieee.org/groups/802/15/pub/2003/Jan03/03041r7P802-15_TG3a-Down-Selection-Voting-Procedure.doc

http://grouper.ieee.org/groups/802/15/pub/2003/Jan03/03031r6P802-15_TG3a-PHY-Selection-Criteria.doc

http://grouper.ieee.org/groups/802/15/pub/2003/Jan03/03030r0P802-15_TG3a-Technical-Requirements.doc

http://grouper.ieee.org/groups/802/15/private/802-15list/msg00661.html

http://grouper.ieee.org/groups/802/15/pub/2003/Jan03/02372r8P802-15_TG3a-Call-for-Proposals.doc

November 2004 IEEE P802.15-04/0638r4

• Slide 13 document 15-04-0624-01-003a - if the average UWB Limit is used where do the spikes come from?

• C Band, Cingular, and Satellite Industry comments are against only relaxing the rules.• Pulse-Link and Time Derivative were members of MBOA when against the grant of

waiver.• 802.11g products were shipped under waiver.

The chair stated that we will not have to go to the convention center tomorrow, but will hold the WG sessions in the Hyatt Ball Room across the hall.


Session 9


The next presentation of the day was given by Michael McLaughlin on Detailed DS-UWB simulation results document 15-04-0483-04-003a


Simulation Overview• AWGN and channel models CM1 to CM4• Bit rates range from 9Mbps to 2.0 Gbps• Fully impaired Monte Carlo Simulation

– rake coefficients quantized to 3-bits– 3-bit A to D converter (I and Q channels)– RRC pulse shaping– DFE trained in < 5ms in noisy channel (for bitrates >55Mbps)– Front-end filter for Tx/Rx + 6.6 dB Noise Figure– Packet loss due to acquisition failure

Simulation parameters• Matched filter

– 16 rake taps for 110Mbps and greater– Usually 8 rake taps for rates below 110Mbps– Low complexity simulations of 2 rake taps at 9Mbps

• k=6 convolutional code (k=4 for ≥ 1Gbps)• Equalizer

– 31 Tap DFE for 110Mbps and greater– No DFE used for rates below 110 Mbps

• Low Band Range for 110 and 220 Mbps


November 2004 IEEE P802.15-04/0638r4

• 90% Outage Comparison Mandatory Rates

• Range for 500 and 660 Mbps

• 90% Outage Comparison High Rates

• High Band PerformanceDS-UWB Operating Bands

• Each piconet operates in one of two bands– Low band (below U-NII, 3.1 to 4.9 GHz) – Mandatory– High band (optional, above U-NII, 6.2 to 9.7 GHz) – Optional


What high band performance is expected?• Centre frequency is twice as high => lose 6dB.• 2 x Bandwidth => 2 x Total power => gain 3dB• Expect overall loss of 3dB w.r.t. low band in AWGN.• 3dB loss equates to a range factor ~70%• Simulations show AWGN range for 220Mbps is 16.5 m in low band and 11.7 m AWGN

in high band.• Although there is a loss of 3dB in AWGN, the loss turns out to be less in Multipath

because of the greater frequency diversity and, in some cases, stronger FEC.

• AWGN for high band 220Mbps & 440Mbps

• AWGN for high band 500Mbps & 660Mbps

• CM1 and CM2 range for high band 220Mbps


• CM1 range for high band 440Mbps


• Ultra High Rates:1Gbps, 1.33 and 2.0Gbps

• AWGN range for low band 1000Mbps & 1330Mbps

• AWGN for high band 1Gbps & 1.3Gbps


November 2004 IEEE P802.15-04/0638r4

• AWGN for high band 2Gbps

• CM1 range for low band 1000Mbps

• CM1 range for low band 1000Mbps: 85% outage

• CM1 range for 1Gbps: 80% outage

• CM1 range for 1Gbps: 70% outage



• CM1 range for high band 2000Mbps

• AWGN range comparison

• Multipath range comparison mean range

• Multipath range comparison 90% outage

Questions and answers were on the following points:• Slide 6 document 15-04-0483-04-003a has some old MB-OFDM numbers and needs

to be updated – rates also need to be adjusted to make a fair comparison• Noise calculation numbers – please provide the data – will be put on reflector within a

week• Fading effects – extra implementation lost – why no effects? DFE effects? Higher

data rates change forward error correction. • Will 802.11n affect our work on these low rates? No answer.• Channel estimation? Acquisition algorithm not provided.• What percentage of channels actually error floor? 15% of the time the 1Gbs falls back

to 660Mbs. Including retransmission could make the average less.• What was the transmit power output assumed? Data will be sent to reflector.

The next presentation of the day was given by Roberto Aiello on Facts and misconceptions about MBOA waiver request document 15-04-0627-01-003a


Summary• Summarize main technical points discussed in the comments and reply to the comments


November 2004 IEEE P802.15-04/0638r4

• Clarification on power measurements and power spectral density• Clarification on pulse gating

Summary of Waiver Comments• MBOA- SIG has requested a waiver of the Commission’s frequency hopping

measurement procedures and the “pulse gating” rule in Section 15.521(d), to allow MB-OFDM ultra-wideband (UWB) systems to be tested for average emissions under normal operating conditions, rather than with band sequencing stopped.

• For grant of the waiver:– MBOA-SIG (+170 companies)– Additional individual filings: WiMedia Alliance, Renesas, Time Domain, Philips,

Focus, Cetecom, HP, WiLinx, Alereon, and Harris• Against UWB as a whole (spectrum users) :

– C-Band Coalition, Satellite Industry Association, Cingular• Against grant of the waiver:

– Freescale, Motorola, Pulse~LINK, Time Derivative, decaWave

Summary of main opposing comments• MB-OFDM will increase the potential for interference

[not true, as shown on the record]• Granting the Waiver will give MB-OFDM an unfair advantage (increased range) relative

to other UWB technologies [not true, even by opposer’s claims]

• MBOA technical justification is filled with errors– Inclusion of WGN in comparisons ‘masks’ MB-OFDM interference potential

[thermal noise and other interference sources are a reality]– Wrong BER operating point

[BER criterion based on quasi-error free performance]– Field measurements are invalid

[same position and separation distance tests are valid and reflect real systems]– Simulations results are wrong

[simulation results supported by lab and field measurements]– APD analysis is erroneous [shown to be technically accurate using NTIA code]

• Waiver will ‘open the door’ to other systems seeking relief from the rules [scope of Waiver is narrow and does not impact most of the FCC rules]

• FCC should wait for more data and delay making a ruling [reply comments provide comprehensive data; no new information will come from

more tests]• Waiver is not in the public interest and will negatively impact small businesses

[MBOA SIG represents 170+ companies, including many small start-ups]Granting the waiver is in the public interest and is supported by significant technical data showing there will be no increased potential for interference


November 2004 IEEE P802.15-04/0638r4

Summary of technical points• No greater harmful interference

– All UWB signals will be well below the system noise floor of C-band satellite receivers which makes differences between waveforms negligible

– MB-OFDM will look like WGN to narrow bandwidth systems (less than a few MHz), including OFDM systems with narrow tone spacing

– MB-OFDM systems do not synchronize and will not increase the potential for aggregation of interference

– MB-OFDM has been consistently shown to be less harmful than a class of impulse radios allowed by the rules, supported by analysis, simulations, lab measurements, and field measurements

• Differences between all UWB signals allowed by the rules are within a few dBs when measured in realistic scenarios

• MB-OFDM technology advantages– Band switching (the multi-band concept) increases frequency diversity, provides

course spectrum flexibility at Tx, enables efficient CMOS designs, and provides protection from strong interferers at Rx

– OFDM efficiently captures multipath energy, shares common components with other technologies (WiFi, WiMax, DSL) leveraging best known methods in design and manufacturing, provides fine spectrum flexibility at Tx, and enables efficient signal processing techniques for interference mitigation in Rx

– Spectrum flexibility will be necessary to enable worldwide interoperability and to adapt to future spectrum allocations

à MB-OFDM gives unique advantages at practical cost and complexity

Clarification on power measurements and power spectral densityFCC measurements

• Peak instantaneous power : operating measurement device uses max hold that records the peak power in an equivalent 50MHz bandwidth obtained over a window of time, a defined span of frequencies and over all possible of orientations to obtain the maximum instantaneous power over these three parameters (time, frequency, & orientation). This limit is 0dBm.

• Average PSD : is measured in a 1MHz resolution bandwidth and averaged over 1ms of time and is maximized over all possible orientations of the device. This limit is -41.3dBm/MHz.

Wrong Claim on Power Level • From Freescale waiver comments:

• Somewhere in the spectrum, at every instant [emphasis added], the MBOA system would be emitting at three times the [power] level permitted to an impulsive or direct sequence system.

Why this is wrong:1. “Instantaneous power level” has meaning only in the time domain. Clearly many

impulse-based systems permitted by the rules have higher instantaneous time-domain


November 2004 IEEE P802.15-04/0638r4

power levels than MB-OFDM does.2. In the frequency domain, power spectral density (dBm/MHz) cannot be measured in an

“instant”. Some averaging time must be specified, such as the 1 ms interval designated in the rules. Even under the shortest interval found on high-end analyzers (10 ms), average and peak PSD for MB-OFDM comply with the rules. See charts that follow.

Average-Power Compliance• MB-OFDM waveform, measured under authentic operating conditions, conforms to Part

15 requirements not to exceed -41.3 dBm/MHz PSD.

Peak Power Compliance• MB-OFDM waveform, measured under authentic operating conditions, conforms to Part

15 requirements not to exceed 0 dBm peak power.

MB-OFDM Spectrogram (no averaging)

MB-OFDM Spectrogram (averaging over 500ns)

MB-OFDM Spectrogram (averaging over 750ns)

MB-OFDM Spectrogram (averaging over 1us)

Slide 15 document 15-04-0627-01-003a• This plot is wrong because PSD limit refers to average PSD

For both MB-OFDM and DS-UWB waveforms have the same average PSD for averaging time > 1 us

Pulse gatingWhy pulse gating is different

• Pulse gating is not an inherent and natural consequence of implementing a legitimate bandwidth expansion method

– Slow pulse gating does not increase bandwidth, diversity or interference immunity.

• MB-OFDM waveform explicitly relies on TFI coding to achieve bandwidth expansion design objective

• The peak amplitudes introduced by true pulse gating can be resolved by a much larger class of existing victim receivers (e.g., with 4MHz bandwidth or less).

– MB-OFDM, as proposed, need victim bandwidths >>4MHz to cause the peak values to rise significantly above those for continuous AWGN

Sidebar:It’s the energy per bit that counts!

• Like the speed of light or conservation of energy in physics, energy per bit is a


November 2004 IEEE P802.15-04/0638r4

fundamental constraint.• This is why engineers rightly compare one scheme to another via their respective BER vs

Eb/No curves.• A UWB design could “cheat” and gain a true advantage over another if, and only if, it

somehow allowed for a higher value of Eb.• MB-OFDM and DS-UWB have identical values for Eb. The waiver aims to keep it that

way.• Not granting the waiver would force ~75% reduction in Eb for MB-OFDM relative to all

other schemes. That would handicap MB-OFDM.

Conclusions• MB-OFDM waveforms, when measured as described in the Waiver, will not cause greater

interference than waveforms already allowed by rules• The properties of MB-OFDM waveform result from the pursuit of legitimate design goals,

rather than an attempt to transmit at "5dB higher power than allowed by the rules." • The average power and associated energy per bit is identical to other waveforms of the

same overall bandwidth. • The potentially increased peak-to-mean ratios compared to a steady-state (stationary)

waveform are strictly constrained by the limited scope of the waiver to 3 bands sequence

Questions and answers were on the following points:• Slide 9 & 10 document 15-04-0627-01-003a

• If this is 1 ms measurement how was it possible – TDK made these measurements and external amplifiers used with FCC approved test procedures.

• 3-D plots with and without averaging – which plot most closely is what a C-Band receiver sees? Interference is what is important. Record shows that it does not interfere. We can not compare peak with average limit. These plots are not the best way to understand the real interference.

• Slide 18 document 15-04-0627-01-003a• This should be backed up by some kind of authority, but not sure who. This

explains the basic justification. It also shows the system designer what to look for when designing a good UWB system.

• Original R&O considered pulses. The waiver has solid base and should be approved

• Slide 3 document 15-04-0627-01-003a• Grant this waiver in a fair and universal way

• Gating – DS signal on for 200ns and off for 200ns is this a gated signal? Answer: Yes• FCC has done a great job on UWB. We should trust their opinion on the waiver. What do

we do? • What is the real interference? Real testing results. Criteria? There are some different

assumptions like noise, in the error results.• Bandwidth expansion without frequency hopping is possible with MB-OFDM. Why the

waiver? It was a power consideration.


November 2004 IEEE P802.15-04/0638r4

The chair then said we have two volunteers for technical editor, Matt Welborn and Charles Razzell. He said we will do as we have before, and have co-editors.He stated that the objective for January is the second confirmation.

Ian Gifford made a motion to adjourn and Anuj Batra seconded. The chair asked if there was any discussion or objections. There were none.

The meeting adjourned at 5:24 PM


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