Project:%20IEEE%20P802.15%20Working%20Group%20for%20Wireless%20Personal%20Area%20Networks%20(WPANs)

1
Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
MB-OFDM No Vote Responses Date Submitted Nov
15, 2004 Source Matthew B. Shoemake and John
Terry, Joy Kelly and Jim Lansford, David Leeper
and Jeff Forrester, Joe Decuir, Charles Razzell
Company WiQuest, Alereon, Intel, MCCI,
Philips Address 8 Prestige Circle, Suite 110,
Allen, Texas 75013 Voice1 214-547-1600, FAX
1 214-547-1606 E-MailProvided throughout
document Re IEEE 802.15.3a No Vote Responses
from September 2004 Vote Abstract This
presentation contains no vote responses to
comments submitted after the IEEE 802.15.3a
downselect vote in September 2004. These
responses have been complied by multiple
supporters of the Multiband OFDM approach as
indicated throughout the document. Purpose The
purpose of this presentation is to address no
vote responses thereby enabling an affirmative
vote during the confirmation step and thereby
enabling IEEE 802.15.3a to move forward into the
working group balloting stage of
standardization. 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.
2
Outline

1. Introduction Matthew Shoemake, WiQuest
2. Regulatory Compliance and Interference Joy
   Kelly, Alereon
3. MAC Matthew Shoemake
4. Location Awareness Joe Decuir, MCCI
5. Harmonization or Coexistence David Leeper,
   Intel
6. Multipath Performance Charles Razzell, Philips
7. Time to Market Jim Lansford, Alereon
8. Summary

3
Regulatory Compliance and Interference

• Charles Razzell, Philips, charles.razzell_at_philips.
  com
• Jeff Foerster, Intel, jeffrey.r.foerster_at_intel.com
  
• Joy Kelly, Alereon, joy.kelly_at_alereon.com

4
Overview of FCC Compliance / Interference Section

• Many no vote comments have been elaborated on in
  reply comments made in response to the MBOA
  waiver request
• Following slides review significant points raised
  and provide technical analysis, simulations, lab
  measurements, and field measurements
  demonstrating that
• MB-OFDM waveforms, as proposed in the Waiver,
  will not cause greater interference than
  waveforms already allowed by rules
• This body of work is precisely what was requested
  by FCC/OET (i.e. to demonstrate no greater
  interference potential than waveforms allowed by
  the rules)
• MB-OFDM devices operating under the proposed
  Waiver will comply with the Part 15f limits on
  peak and average power

5
Summary of main opposing comments claims

• MB-OFDM will increase the potential for
  interference
• Not true, as will be shown here
• Granting the Waiver will give MB-OFDM an unfair
  advantage (increased range) relative to other UWB
  technologies
• Not true, even by opposers claims
• 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 on the
  3-band MB-OFDM waveforms
• Waiver is not in the public interest and will
  negatively impact small businesses
• MBOA SIG represents 170 companies, including
  many small start-ups

6
Summary of main opposing comments 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 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

7
Summary of technical points

• No greater interference than systems allowed by
  FCC rules
• All UWB signals will be well below the system
  noise floor of C-band satellite receivers
• Makes differences between waveforms negligible
• MB-OFDM looks 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 have less
  interference 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
• Bandwidth of information-carrying tones is 503.25
  MHz

8
Summary of technical points (cont)

• MB-OFDM technology advantages
• Band switching (the multi-band concept)
• increases frequency diversity
• provides coarse spectrum flexibility at Tx
• enables efficient CMOS designs
• 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

9
No greater interferenceC-band
satellites802.11a devices Other UWB devices No
risk of aggregation
10
C-band Satellites

• C-band satellite systems have little margin
• MBOA field measurements have confirmed this (only
  2.5 dB margin)

Table 1 Power spectral density limits for some
US government bands
11
C-band Satellites (cont)

• C-band satellites have low margin due to
  challenges of communicating over long satellite
  link (see Petition for reconsideration of
  Satellite Industry Association in docket 98-153)
• Low margin requires interference to be below
  systems noise floor of C-band satellite receiver
• What is system noise floor for C-band satellites?
  
• From SIA, Isat is defined as the interference at
  a given C-band receiver caused by adjacent C-band
  channel interference and cross polarization noise
  from the satellite link
• Isat/N 1.4 dB (1.38)
• N_sys N I_sat where N is the thermal noise
  floor
• FCC adopted criterion of IUWB /N lt 0 dB (docket
  98-153 March 12, 2003)
• N_sys N I_sat (1 1.38) 2.38
• IUWB /N_sys 10log10(1/2.38) -3.8dB

12
C-band Satellites (cont)

• FCC criterion, when incorporating total satellite
  system noise experienced (as defined by SIA) is
  thus
• IUWB /N_sys -3.8dB
• Further support of appropriate protection levels
  for C-band satellites
• XtremeSpectrum filed response to SIA Petition for
  Reconsideration (Sept 4, 2003 in docket 98-153)
  stating that
• Using SIAs stated operating levels, XSI now
  part of Freescale demonstrates that an I/N of 6
  dB assigned to a UWB device is an appropriate
  protection level
• IUWB /N -6 dB ? IUWB /N_sys -9.8dB

13
C-band Satellites (cont)

• Simulation results from an Alion report presented
  to FCC (Feb 11, 2004)
• Based on simulation results, coalition of C-band
  constituents proposed reducing current FCC limits
  by 21dB (98-153 02-380 February 18, 2004)
• Motorola (in ET Docket No. 98-153, April 9, 2004)
  provided analysis in response to Alion report
  which took into account more realistic factors
  into the simulations. Motorola concluded that
• Based on the revised simulations with the more
  realistic path loss models, building blockage
  effects for devices of high in the air (and near
  the antenna main beam), the inclusion of a
  realistic duty cycle (lt10) and realistic density
  projections, it is clear that no significant
  interference will result. The aggregate UWB
  signal power levels drop by 25-60 dB when more
  realistic assumptions are made in the
  simulations.

14
C-band Satellites (cont)

• UWB average interference power will be well below
  system noise floor when considering realistic
  deployment scenarios
• When I/Nsys ltlt 0 dB, simulations, lab
  measurements, and field measurements show little
  difference between MB-OFDM, impulse, and DS-UWB
  waveforms
• Results also consistently show MB-OFDM causes
  less interference than impulse radios already
  allowed by the rules

15
C-band Satellites (cont)

• Supporting analysis from other companies
• Freescale commented that when you mix one part
  MB-OFDM energy with 20 parts Gaussian noise, the
  result is a composite signal that looks very much
  like noise.
• TimeDerivative commented that At very low I/N
  ratios the noise dominates and little can be said
  about the difference between various
  interferers.
• ? This is precisely the point to simulate,
  analyze, and measure the interference potential
  of alternative UWB waveform types in a realistic
  operating environment

16
MBOA C-band Satellite field test results

• Field test objectives
• Measure interference potential to C-band TV
  service operating in the FSS C-band 3.7-4.2GHz
• Compare White Gaussian Noise (WGN), MB-OFDM
  Impulse UWB signals
• Quantify relative interference potential of each
  UWB signal
• Determine safe distance from dish antenna to
  avoid interference
• Two separate tests were conducted.
• First test compared the different UWB signals
  in terms interference potential to the FSS
  receiving system.
• Second test determined the safe distance from
  the dish that must be maintained to avoid
  interference to the FSS receiver

17
MBOA C-band Satellite field test results

• Same position testing
• Set UWB emissions to -41.3 dBm/MHz for each
  waveform type
• Measure interference power of each UWB waveform
  type required to yield visible block artifacts on
  TV monitor
• Interference power measurement to produce visible
  block artifacts accurate to within 0.1 dB
• Shows relative differences between waveforms
• Devices being in near-field of antenna is
  irrelevant
• Separation distance testing
• Devices had to be very close to antenna (in the
  near-field) to see measurable interference
  levels
• Results are not random and show UWB devices
  must be very close before interference is
  measurable

18
MBOA C-band Satellite field test results Same
Position Testing

• MB-OFDM has less interference than impulse radio
  and within 1-1.6 dB from WGN
• Simulations and lab measurements support this
  result

Emission 0.5dB above sensitivity 1dB above sensitivity 2.5dB above sensitivity
3MHz PRF impulse 0.0dB 0.0dB 0.0dB
MB-OFDM 3 band 0.8dB 2.6dB 2.4dB
WGN (DSSS) 1.9dB 3.8dB 4.0dB
19
MBOA C-band Satellite field test resultsSafe
Distance Tests
MB-OFDM
WGN
Dish Orientation
Scale in feet
20
Interference to 802.11a

• interference measurements were conducted, using
  an IEEE802.11a device
• Two types of the interfering signals were
  considered
• MB-OFDM signal
• AWGN

21
Test Set-up for Interference Measurements to
802.11a
22
Test Description

• An IEEE802.11a device was configured with the
  data-rate of 36 Mbps (16 QAM, R3/4)
• The IEEE802.11a signal power was calibrated to
  the sensitivity level (0 dB at BER10-5) in the
  absence of the interference.
• This defines the operation thermal noise level.
• IEEE802.11a signal level was adjusted to
  different levels in order to measure the impact
  of the interference signal and its power.
• With the interference added to the calibrated
  thermal noise, its power level (maximum tolerable
  interference power (MTIP)) was measured to
  maintain the IEEE802.11a reception at BER10-5.

23
Interference to 802.11a
Measurement results
Signal Power of 802.11a above sensitivity I/N Difference between AWGN and MB-OFDM Interference
10 dB 9.5 dB 0.5 dB
3 dB 0 dB 0.5 dB
2 dB -2.3 dB 0 dB
1 dB -5.9 dB 0 dB
0.5 dB -9.1 dB -1.5 dB

• MB-OFDM produces no more interference to IEEE
  802.11a WLANs than AWGN
• 802.11a is OFDM based and uses symbol periods of
  4 usec
• This results in integration over several MB-OFDM
  symbols, so only average interference power
  matters

24
Example BER results for 802.11a comparing MB-OFDM
AWGN
25
802.11a AGC Performance in the Presence of
MB-OFDM Transmission

• Contention that the MB-OFDM signal would cause
  performance degradation of the AGC in the
  IEEE802.11a receiver.
• Comparison was made in the IEEE802.11a packet
  detection and the AGC convergence performances
  between the MB-OFDM signal and AWGN.
• Measurement was conducted with the IEEE802.11a
  device operating at 3 dB above sensitivity.
• conducted with the MB-OFDM signal level set to
  the MTIP level as well as to 10 dB higher than
  the MTIP level.
• There was no detectable impact whatsoever of the
  MB-OFDM signal to the IEEE802.11a packet
  detection and AGC performance.

26
802.11a Packet Detection AGC Performance in
Presence of AWGN MB-OFDM Interference
27
MB-OFDM Interference Impacts to 802.11a Systems
Conclusions

• 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

28
Opponents Claims regarding MB-OFDM Interference
to other UWB systems

• 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.
• 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.
• TimeDerivative states This additional power
  poses a significant additional risk to other UWB
  communications equipment.
• ? No evidence has been shown to support these
  claims.

29
Reality MB-OFDM Interference to other UWB systems

• On the contrary, consider the following example
• Assume an MB-OFDM signal which occupies a total
  bandwidth of 3528 1584 MHz
• peak power spectral density (PSD) during the OFDM
  symbol on time is 5.8 dB above average PSD
• 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,
  Freescales 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.

30
Reality MB-OFDM Interference to other UWB systems

• At any given instant, one 500 MHz portion of
  impulse radios 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 power1
  at the output of a 1584 MHz matched filter is
• IMB-OFDM (-41.3 5.8) dBm/MHz 10log10(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.

31
Reality MB-OFDM Interference to other UWB systems

• 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) 10log10(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.
• including system noise in addition to the
  interference
• Accounting for target DS-UWB system FEC protection

32
MB-OFDM systems will not increase aggregate
interference levels

• Freescale and others claim a MBOA device seeks
  out and transmits on channels momentarily left
  vacant by others
• This requires nanosecond time-scale
  synchronization between devices belonging to
  different networks NOT facilitated by MBOA
  protocols
• Uncoordinated MBOA devices pick different
  time-frequency codes (TFC) using similar
  protocols as other UWB devices do in order to
  select logical channels corresponding to their
  PHYs
• timing offsets between uncoordinated devices are
  random
• timing drifts between uncoordinated devices
  further randomize emissions

Unrealistic fine-scale Synchronization NOT
facilitated for MBOA devices belonging to
different networks
Aggregation results for MB-OFDM devices are no
different than those for pulse based UWB devices
33
No greater interference Comparisons of various
UWB waveforms impact to a generic wideband DVB
receiver
34
Victim Receiver

• The victim receiver chosen for study was a
  Digital Video Broadcasting receiver with the
  following characteristics
• QPSK modulation with a transmission symbol rate
  RS of 33 Msymbols/second
• Root Raised Cosine Filtering at Tx and Rx
• Viterbi FEC, with rates of 1/2, 2/3, 3/4, 5/6 and
  7/8.
• Representative of the most vulnerable class of
  victim receivers
• Very wide bandwidth and low error rate
  requirement
• BER at output of Viterbi decoder for comparisons
  2 x 10-4 (Quasi-error free operating point for
  satellite systems employing standard concatenated
  code)

35
BER Criterion for Digital Video

• Freescale claims that the MBOA analysis is based
  upon the wrong BER criterion and stated that the
  BER used in our comparisons were 7 orders of
  magnitude higher than the specification. They
  claimed that the curves and corresponding
  conclusions are misleading, and to a skilled
  communications engineer, they are fatally flawed
  and have no technical merit. 
• It is well-known that digital video needs a low
  BER.
• it is also well-known that a BER of 2 x 10-4 at
  the output of the Viterbi decoder yields
  quasi-error free performance at the output of the
  Reed-Solomon decoder (meaning a BER of 10-10 to
  10-11)1.
• Therefore, comparing the performance at the
  output of the Viterbi decoder at a BER of greater
  than or equal 2 x 10-4 is completely relevant to
  this discussion

36
Fundamental assumptionsWhat is the right BER
criterion?

• MBOA, Freescale, and TimeDerivative each proposed
  different BER operating points to do comparisons
• Alion studies, MBOA studies, and Motorola studies
  all used digital C-band satellite equipment
  employing the same FEC as described in ETSI EN
  300 421 V1.1.2
• Requirements suggest interference impacts would
  occur somewhere above a BER of 2 x 10-4 after the
  Viterbi decoder
• MBOA has provided substantial data at this
  operating point as well as at other operating
  points

The following table and text is copied from ETSI
EN 300 421 V1.1.2
37
Fundamental assumptions System Noise must be
considered in the analysis

• MBOA and Freescale have a fundamental difference
  of opinion with respect to inclusion of system
  noise in comparisons of different waveforms
• MBOA position is simple
• System noise is a realitywhy ignore it?
• System noise thermal noise intra-system
  interference
• When average UWB interference power is well below
  the system noise floor, differences between UWB
  waveforms are negligible (even Freescale agrees)
• Even at moderate I/N levels, differences between
  various UWB waveforms are small
• Misleading conclusions result when not
  considering realistic environments
• Differences between waveforms are highly
  exaggerated when measured in unrealistic,
  noise-less environments
• ? System noise must be considered in any
  interference analysis

38
Noiseless 7/8-Rate Coded Results
Impulse radio at 1MHz PRF
INTERFERER ONLY NO THERMAL NOISE!
0
10
-1
10
MB-OFDM 1,1,3,3,2,2
7/8-rate coded QPSK BER
MB-OFDM 1,2,3,1,2,3
impulse simulation
MB-OFDM 1,2,3,1,2,3
WGN noise only
MB-OFDM 1,1,3,3,2,2,
WGN only
Eb/Io dB
Why was the impulse-induced error rate not
completely corrected by the FEC? ? Easily
explained by looking at free distance of code and
collision properties
39
Impulsive Interference and FEC

• At equal power levels, impulse amplitude is 16dB
  greater than wanted QPSK signal.
• Soft decisions associated with collisions will be
  highly confident (and wrong).
• Impulse interference pollution of the Viterbi
  path metrics may last for quite some time and
  cause an associated error burst.
• The duration of the negative impact of an impulse
  is much longer than that of the impacted bits,
  especially where Viterbi decoding with soft
  metrics is used.
• Soft decisions must be clipped in magnitude to
  prevent excessive error propagation.

Real part of received QPSK waveform
Real part Interfering Impulse
40
¾-rate Coded Results (with noise)
I/Nsys -10.0, soft metric clipping
At I/Nsys-10dB, there is very little difference
between the impact of extra Gaussian noise and
any of the other types of interference studied.
XSI (now Freescale) filed comments in support of
this I/N level Using SIAs stated operating
levels, XSI demonstrates that an I/N of 6 dB
assigned to a UWB device is an appropriate
protection level. ? I/N-6 dB corresponds to
I/Nsys-10 dB
0
10
impulse simulation
MB-OFDM 1,2,3,1,2,3,
WGN noise WGN int.
-1
10
MB-OFDM 1,1,3,3,2,2,
0.75-rate coded QPSK BER
Eb/No dB
Nsys thermal noise intra-system interference
41
¾-rate Coded Results (with noise)
I/Nsys -5.0, soft metric clipping
0
10
At I/Nsys-5dB, we begin to see a clear ordering,
with the impulse radio being the worst case. The
spread, however, is only 1dB. this is quite a
severe case, requiring very close proximity to
the victim satellite receiver dish.
impulse simulation
MB-OFDM 1,2,3,1,2,3,
WGN noise WGN int.
MB-OFDM 1,1,3,3,2,2,
0.75-rate coded QPSK BER
Eb/No dB
42
¾-rate Coded Results (with noise)
I/Nsys 0.0, soft metric clipping
0
10
At I/Nsys0dB, the same ordering is maintained,
with the impulse radio being the (co-equal) worst
case. This is a highly exaggerated and very
unlikely case, considering that even the White
Gaussian interferer has reduced the available
link margin by 3dB, enough to cause link failure
in many installations.
impulse simulation
MB-OFDM 1,2,3,1,2,3,
WGN noise WGN int.
-1
10
MB-OFDM 1,1,3,3,2,2,
0.75-rate coded QPSK BER
Eb/No dB
43
½-rate Coded Results (with noise)
I/N 0.0, soft metric clipping
This is (again) a highly exaggerated and very
unlikely case, considering that even the White
Gaussian interferer has reduced the available
link margin by 3dB, enough to cause link failure
in many installations. Nevertheless, the spread
in susceptibility to the various waveforms is
lt2.1dB at the target BER of 2x10-4.
impulse simulation
MB-OFDM 1,2,3,1,2,3
WGN noise only
-1
10
MB-OFDM 1,1,3,3,2,2,
-2
10
½-rate coded QPSK BER
-3
10
-4
10
1
2
3
4
5
6
7
8
9
10
Eb/No dB
44
½-rate Coded Results (with noise)
The ability of the FEC to deal with impulsive
interference depends on its strength. With a
very strong FEC, such as the ½-rate code used
here (dfree10), it can happen that the impulsive
interference is better tolerated than the MB-OFDM
waveforms. However, the absolute difference
remains small (the spread between all waveforms
is less than 1dB).
Differences of 2 dB or less are WITHIN
measurement tolerance of instrumentation
45
LAB Measurement Results

• Results show that the order of interference
  impact starting with most benign is
• AWGN
• 3MHz PRF impulses
• Cyclic Prefix MB-OFDM
• Zero Prefix MB-OFDM
• 1MHz PRF impulses

Relative impact and degree of impact from lab
measurements resemble those from the simulations.
46
Conclusions on Interference Impact on Wideband
DVB Receiver

• For rate ¾ and 7/8 codes, MB-OFDM is more benign
  than a 1MHz impulse radio.
• Our simulations and measurements focused mainly
  on the ¾-rate code as being a representative
  choice from the available rates 1/2, 2/3, 3/4,
  5/6, 7/8.
• Low rate codes (½-rate code, for example) are
  slightly more tolerant to the 1MHz PRF impulses
  than to MB-OFDM waveforms
• Differences are still small among all the
  waveforms, when realistic I/Nsys ratios are used.
• Interference analysis with a low rate code is not
  representative of a worst-case situation (i.e.,
  a UWB device needs to be much closer to a victim
  using a low rate code compared a victim using a
  high rate code)

Under realistic, worst-case scenarios, MB-OFDM
produces consistently less interference than a
class of impulse radios already allowed by the
rules
47
No greater interference APD Analysis
48
APD Analysis

• APD plots have been used by the NTIA in the
  course of interference studies and have been
  described as a very informative measurand. (See
  NTIA Report 01-383.)
• It is important to be aware of the limitations of
  APD plots, and we agree that they are not
  susceptibility tests and should be viewed in
  conjunction with detailed simulations, lab
  measurements, and field measurements supplied by
  the MBOA.
• However, we do still value APD plots (as does the
  NTIA) for their ability to describe the potency
  of an interfering waveform, irrespective of the
  particular modulation and channel coding scheme
  used

49
Variation with I/Nsys ratio
20

• The plotted curves all show rather high (and in
  some cases extremely high) I/N ratios.
• In order to observe differences in susceptibility
  of as much as 5dB relative to AWGN
• The I/N ratio must be at least 8dB AND
• The receiver must respond to peak events with a
  probability as low 10-6 AND
• The bandwidth of the victim must exceed 16MHz

MB-OFDM I/N -6.0 dB
MB-OFDM I/N -3.5 dB
15
MB-OFDM I/N 0.0 dB
MB-OFDM I/N 8.0 dB
10
noise alone
5
0
dBV relative to mean
-5
-10
-15
-20
-25
-30
0.0001
0.01
0.1
1
5
10
20
30
40
50
60
70
80
90
95
98
99
percent exceeding ordinate
APD analysis proves large impact (5 dB as claimed
by Freescale) is only possible when a large
bandwidth receiver with no FEC is in extremely
close proximity to a MB-OFDM device. Joint
probability of this event is vanishingly small.
50
Variation with Victim Rx BW
APD plots for MB-OFDM using 1,1,3,3,2,2 TFI code
APD plots for MB-OFDM using 1,2,3,1,2,3 TFI code
20
20
bw2MHz
bw2MHz
bw4MHz
bw4MHz
bw8MHz
bw8MHz
10
10
bw16MHz
bw16MHz
bw32MHz
bw32MHz
0
0
Amplitude relative to mean dBV
-10
-10
-20
-20
-30
-30
-40
-40
-50
-50
0.0001
0.01
0.1
1
5
10
20
30
40
50
60
70
80
90
95
98
99
0.0001
0.01
0.1
1
5
10
20
30
40
50
60
70
80
90
95
98
99
percent exceeding ordinate
percent exceeding ordinate

• 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).

51
Summary of APD results

• APD analysis is correct and verified using NTIA
  code
• 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).

52
Summary of APD results

• A very specific (and unlikely) combination of
  circumstances must occur to support a required
  SIR protection difference of 5dB as claimed by
  opponents of this waiver including
• Very wide victim receiver bandwidth
• Extraordinary and improbable I/N ratios not
  anticipated by the 2002 UWB RO
• No error correction capability for the victim
  receiver.
• ?Under realistic I/Nsys ratios, APD analysis
  shows MB-OFDM only deviates from WGN by a few dBs
  a small percentage of time

53
MB-OFDM Power Levels
54
Claims regarding Power Level (1)
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 misleading
• Instantaneous power level has meaning only in
  the time domain. Clearly many impulse-based
  systems permitted by the rules have higher
  instantaneous time-domain power levels than
  MB-OFDM does.
• 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.

55
Average-Power Compliance
-41.3 dBm/MHz
Waiver Reply Figure 21 Example average EIRP
measurement for a MB-OFDM transmitter using
intended operational mode according to the waiver
MB-OFDM waveform, measured under authentic
operating conditions, conforms to Part 15
requirements not to exceed -41.3 dBm/MHz PSD.
56
Peak Power Compliance
0 dBm
Waiver Reply Figure 22 Example Peak EIRP
measurement for a MB-OFDM transmitter
Measurements taken at a RBW of 3 MHz and
compensated by 20Log(3/50) RBW factor to compare
with FCC UWB peak limit in a 50 MHz RBW
MB-OFDM waveform, measured under authentic
operating conditions, conforms to Part 15
requirements not to exceed 0 dBm peak power.
57
Claim regarding Power Level (2)
Freescale claims the waiver would open the door
to waveforms with much higher emission levels
than the current rules allow. Freescale gives an
example of a 3-hop system that is 12.5 of the
time gated on and 87.5 of the time gated off.

• Why this is false
• Freescales example would clearly violate
  existing peak power limits and would not be
  permitted under the rules.
• The waiver does not seek change to any existing
  power limits.
• The waiver narrowly seeks FCC approval to have
  measurements for a 3-band MB-OFDM system made
  under authentic operating conditions as it would
  actually be deployed.

58
MB-OFDM Bandwidth
59
Claim Regarding Bandwidth
Freescale claims the MB-OFDM waveform with
hopping turned off may not meet the minimum 500
MHz bandwidth requirement.
Why this is false Each MB-OFDM symbol consists
of 122 data-bearing sub-carriers (110 data 12
pilot). Each sub-carrier is 4.125 MHz from its
nearest neighbor. 122 4.125 MHz 503.25 MHz
The MB-OFDM waveform meets the minimum 500 MHz
bandwidth requirement at all times with or
without frequency sequencing turned off.
60
MB-OFDM Technology Advantages for Coexistence
with Existing Future Services
61
Benefits of MB-OFDM Systems

• Superior multipath performance of OFDM signals
• Advantages of OFDM well-known to the industry and
  is used in WiFi, WiMax, DSL, and other
  communications systems
• Implementation much less complex than rake
  receiver required for impulse radios
• Innovative use of spectrum by partitioning into
  528 MHz bands (band switching is fundamental to
  the design)
• Reduces overall system complexity and power
  consumption due to lower bandwidth filters,
  analog-to-digital and digital-to-analog
  converters, etc.
• Enables CMOS friendly designs utilizing lower
  bandwidth baseband analog components
• Interleaved 3 bands sequenced in time provides
  1.5 GHz spectrum use for improved frequency
  diversity
• Enables suppression of strong narrowband
  interferers at the receiver by utilizing lower
  bandwidth analog baseband filters to limit
  compression of ADC (allows for designs with steep
  filter roll-offs), strong FEC coding, and digital
  signal processing techniques

62
Coexistence Benefits of MB-OFDM Systems (1)

• Spectral emissions advantages
• Inherent properties of OFDM waveform produces
  lower out of band emissions than other types of
  UWB waveforms
• Fine grained ability to sculpt emissions spectrum
  via software to meet worldwide regulatory
  requirements and extremely stringent coexistence
  requirements for some applications (operation
  within 1 foot of another wireless system or
  multiple radios in the same device)

Added protection by dropping a whole band
Software controlled notch
63
Coexistence Benefits of MB-OFDM Systems (2)

• Why is spectrum flexibility critical?
• Desire single solution to support worldwide
  regulations and interoperability
• Benefits of scaling (single SKU supports larger
  population of devices)
• Interoperability between devices in different
  regions (take a devices from the US to Europe and
  it can still work via software control
  mechanisms)
• Challenges different frequency allocations
  worldwide may require different emissions limits
• Indoor WiMax systems in Europe operate in 3.4-3.6
  GHz band
• RAS bands in EU and Japan span large part of 3-10
  GHz bands (uncertain what regulatory bodies will
  require for these bands)

3260-3267 MHz 3345.8-3352.5 MHz 4950-4990 MHz 6650-6675.2 MHz
3332-3339 MHz 4825-4835 MHz 4990-5000 MHz 10.6-10.68 GHz
64
Coexistence Benefits of MB-OFDM Systems (3)

• Adapt to future allocations in the US and
  worldwide
• Dont want to change UWB solution every time FCC
  allocates new spectrum which may operate in close
  proximity to a UWB device (impacts Tx and Rx)
• New 3.65-3.70 GHz NPRM could be useful for WiMax
• 4G licensed allocations in the 3-4 GHz band being
  considered in many countries
• UWB solutions expected to operate in very close
  proximity to cell phones (within a few feet) and
  will likely be integrated into cell phones
  requiring greater protection

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)
65
MAC

• Matthew B. Shoemake, WiQuest
• matthew.shoemake_at_wiquest.com

66
No Vote Comments MAC

1. As a (potential) IEEE standard, MB-OFDM must show
   that it is specified to work with the current
   IEEE 802.15.3 MAC, with minimum modifications.
2. Public statements by both the companies and
   industry organizations referenced by the MB-OFDM
   proposers make it clear that they intend to
   develop and deploy a different MAC layer for
   their UWB products. This means that the companies
   and organizations that are referenced as backing
   the MB-OFDM proposal do not intend to use the
   802.15.3a MAC and therefore would not use the
   802.15.3a standard.
3. It appears from multiple sources in the popular
   press as well as MBOA-SIG Press Releases that the
   MBOA MAC specification will be the only one
   certified by the WiMedia to work in the MBOA
   ecosystem. If there is no intention to use the
   IEEE Std 802.15.3-2003 and this is merely a
   blatant attempt to hijack the IEEE brand then I
   submit that the IEEE 802.15 mandate withdrawal of
   the Merged Proposal 1 and confirm Merged
   Proposal 2.

67
Comment 1 Support of .15.3 MAC ?

• The MultiBand OFDM PHY proposal is designed to
  work with the IEEE 802.15.3 MAC
• 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
• 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

68
Comment 2 Theres a different MAC

• IEEE can not control external organizations nor
  should that be our goal
• The goal of IEEE 802.15.3a is to help
  organizations and companies by setting standards,
  not to force anything upon them
• The existence of multiple MACs should not be a
  distraction to the IEEE 802.15.3a deliberations
• IEEE 802.15.3a can do a service to the industry
  by confirming a new PHY standard

69
Comment 3 WiMedia Certification

• The success of a standard often depends on
  interoperability testing and certification
• The IEEE 802 Standards body has abdicated
  responsibility for testing and certifying
  compliance of products
• Given that, there is no direct control over
  organizations such as Wi-Fi, DOCSIS, WiMedia,
  WiMAX, UNH, etc.
• IEEE standards are intended to help companies and
  the population as a whole including organizations
  like WiMedia
• The IEEE should be supportive and appreciative of
  external organizations that test and certify IEEE
  standards based products

70
Location Awareness

• Joe Decuir, MCCI
• joe_at_mcci.com

71
No Vote Comments Ranging and Location Awareness

• MB-OFDM must have a clear, satisfactory solution
  to solve the location awareness problem.
• MB-OFDM proposal is lacking in acceptable
  location awareness functionality.

72
MB-OFDM PHY supports range measurements

• Ranging is one-dimensional location awareness
• The MB-UWB PHY supports ranging using Two Way
  Time Transfer algorithm (TWTT, 15-04-0050-00-003a)
   
• 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
• 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 subcommittee
• Applications and 2-3 dimensional location
  awareness are above the MAC.
• see 15-04-0300-00-004a-ranging-rf-signature-and-ad
  aptability.doc

73
The MB-UWB PHY ranging support is only a part of
location awareness.

• 802.15 TG3a has seen very little location
  awareness work.
• 802.15 TG4a is actively studying location
  awareness
• see 15-04-0581-05-004a-ranging-subcommittee-report
  
• 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).
• They have studied several algorithms no choice
  have been made.  
• TWTT uses minimal additional hardware 
• Angle-of-arrival requires multiple antennas

74
Coexistence

• David G. Leeper, Intel
• david.g.leeper_at_intel.com

75
No Vote Comments Coexistence

• I suggest that the Merged Proposal 1 and Merged
  Proposal 2 merge and become Merged Proposal 3.
• The clock frequencies and convolutional coder do
  not support a common signaling mode.
• I believe the common signalling mode is a way of
  providing interoperability and coexistence with
  other UWB devices.
• Merge Proposal 2 includes a provision for a base
  signaling mode that would allow multiple PHYs to
  coexist. In order for me to vote yes to Merge
  Proposal 1, there must be some type of
  coexistence mechanism.
• The MB-OFDM proposal must make accomodations for
  the appearance of PHYs in the same space, either
  by some sort of CSM or by a dual PHY.
• The best way to break through current dead lock
  is to adopt a dual PHY standard and let the
  market choose the better.

76
Coexistence or Harmonization (1)

• I suggest that the Merged Proposal 1 and Merged
  Proposal 2 merge and become Merged Proposal 3
• Customers have indicated preference for a single
  PHY standard
• The clock frequencies and convolutional coder do
  not support a common signaling mode.
• 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 devices
• See above
• Merged Proposal _at_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
• See above

77
Coexistence or Harmonization (2)

• The MB-OFDM proposal must make accommodations for
  the appearance of PHYs in the same space, either
  by some sort of CSM or by a dual PHY
• UWB PANs need low power, low cost, and support
  for QoS. CSM and/or dual PHYs would
  unnecessarily impair performance and add
  cost/power consumption
• The best way to break through the current
  deadlock is to adopt a dual PHY standard and let
  the market choose the better
• Customers have indicated they prefer a single PHY
  to a dual PHY. The added expense and power
  consumption brings no benefit to the end user.
  In WLANs, having FH and DS PHYs only confused the
  market no vendor built a viable dual-PHY
  standard product.

78
Multipath Performance

• Charles Razzell, Philips
• charles.razzell_at_philips.com

79
No Vote Comments Multipath Performance

• The performance in range and survivability even
  in moderate multipath is absolutely dismal.
• 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.
• 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 spreading).
• 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.
• 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.
• 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, gt 200 Mps) in order to compensate
  for the degraded performance caused by the
  Rayleigh-distributed multipath fading. Since the
  6 dB degradation (_at_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.

80
Multipath Performance

• 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

Range AWGN LOS 0 4 mCM1 NLOS 0 4 mCM2 NLOS 4 10 mCM3 RMS Delay Spread 25 nsCM4
110 Mbps 21.4 m 12.0 m 12.0 m 11.5 m 10.9 m
200 Mbps 14.6 m 7.4 m 7.1 m 7.5 m 6.6 m
480 Mbps 9.3 m 3.2 m 3.0 m N/A N/A

• The results speak for themselves link distance
  at 110 and 200 Mbps is hardly impacted by
  multipath

81
Multipath Performance cont.

• So, why the counter claims?
• Frequency diversity is not inherent in OFDM
• 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
• In order to overcome this frequency-domain
  spreading is needed, which usually implies some
  redundancy
• Why is this not a big issue?
• Frequency domain spreading in MB-OFDM is provided
  by a mixture of repetition coding and
  convolutional coding
• Even at 480Mbps (the worst case), sufficient
  spreading gain is available to obtain 3m link
  distances in NLOS channels.
• At 110Mbps, the scope for spreading has
  dramatically improved to approximately 6,
  partitioned as a factor 3 for FEC and 2 for
  repetition coding.

82
Time-to-Market

• Jim Lansford, Alereon
• jim.lansford_at_alereon.com

83
No Vote Comments Time-to-Market

• 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.
• 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 competing standard has recently
  geared up it process and is threatening to snatch
  away a sizeable chunk from this standards
  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.
• 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.

84
TTM Issues

• 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

PHY
MAC
85
Summary of comments related to market timing (1)

• 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.
• 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. May we count on you switching your vote?

86
Summary of comments related to market timing (2)

• At least one competing standard has recently
  geared up it process and is threatening to snatch
  away a sizeable chunk from this standards
  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