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

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Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
Harris TG4a CFP Proposal Response Date
Submitted January 2005 Source Rick
Roberts Company Harris Corporation Address MS
1/9842, Box 37, Melbourne, Fl. 32902-0037 Voice
321-729-3018, FAX , E-Mailrrober_at_harris.com
Re Harris TG4a response to call for
proposals. Abstract Harris TG4a response to
call for proposals Purpose For presentation
and consideration by the IEEE802.15.4a
committee Notice This document has been
prepared to assist the IEEE P802.15. It is
offered as a basis for discussion and is not
binding on the contributing individual(s) or
organization(s). The material in this document is
subject to change in form and content after
further study. The contributor(s) reserve(s) the
right to add, amend or withdraw material
contained herein. Release The contributor
acknowledges and accepts that this contribution
becomes the property of IEEE and may be made
publicly available by P802.15.
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Hybrid UWB/UNB1 Communications with Ranging Four
Classes of Devices Class 1 Low Complexity UWB
for Communications with Ranging Class 2
Backwards Compatible UWB with RFI
Protection Class 3 UWB/UNB with propagated
node into GPS denied areas Class 4 High
Precision UWB for Ranging with Communications
Note 1 UNB stands for Ultra-Narrow Band a
technique that uses low frequency, continuous RF
tones for ranging, that require practically no
bandwidth for detection and processing. See
slide 32.
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Class 1 UWB Communications with Ranging
apartment 1
apartment 2
wireless thermostat
AC
AC
Range Assisted Addressing
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Class 2 RFI Protected UWB Communications with
Ranging
Mobile Meter Reader Example
GPS Equipped Truck
Synthetic Triangulation Allows Precise
Localization
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Class 3 UWB/UNB with propagated node into GPS
denied areas
propagated node into GPS denied area
Public Safety Application
UWB
20 m
50 m
Low Frequency Ranging
20 m
Back Channel Out-of-scope (non-ranging)
30 m
802.11
802.11
802.11
command post
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Mandatory UWB PHY
7
Frequency Plan

• Direct Sequence Spread Spectrum
• -3 dB Bandwidth (each band) 666.7 MHz
• Center Frequencies Every 250 MHz (3.6 GHz to
  10.1 GHz)

26 possible overlapping bands
3.6 GHz
10.1 GHz
3.1 GHz
10.6 GHz

• Pulse Response Root Raised Cosine, 25 Excess
  Bandwidth

Fc(-3 dB)333.3 MHz
Fc
250
333.3
Noise Bandwidth (NBW) 666.6 MHz
416.6
8

• Advantages of Multiple frequency bands
• Allows coarse spectral shaping for
  ingress/egress RFI avoidance
• Allows multi-user separation by frequency
  channels
• Allows implementation of lower frequency bands
  in todays CMOS

interference
3.6 GHz
3.1 GHz
Interference avoided by skipping a frequency band
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• Narrower Bandwidth, Spectrally Shaped UWB, Offers
  Advantages
• Spectral Shaping Results in more NBW which means
  more TX power
• 25 Excess BW, Raised Cosine Pulse
• -10 dB bandwidth 708 MHz
• NBW 667 MHz
• Gaussian Pulse
• -10 dB bandwidth 708 MHz
• NBW 388 MHz
• Raised Cosine Pulse Power Advantage 2.35 dB
• More power, better controlled spectrum

• Wider Wavelets offer implementation advantage
• Less complexity if a RAKE is deployed
• 666.6 MHz of bandwidth still offers good
  multipath resolution

10

• Spectral Shaping within a frequency channel
• delay and add notch formation
• delay may be either a delay line or second
  impulse generator

f
f
t0
t1
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• CDMA spread spectrum within each frequency
  channel
• Chipping rate 666.6 Mcps, 25 root raised
  cosine, Nyquist filtering
• Bit Rate (Rb) options (1 bit per symbol)
• Coherent 1 Mbps, 500 Kbps, 250 Kbps, 125 Kbps
• Non-Coherent 62.5 Kbps
• Symbol Duration gtgt Delay Spread (shouldnt need
  DFE)
• Number of chips per bit
• 1 Mbps 666
• 500 kbps 1332
• 250 kbps 2664
• 125 kbps 5328
• 62.5 Kbps 10656
• Actual codewords are TBD (ternary symbols 1,
  -1, 0)
• Processing gain (PG) 28.2 dB to 40.3 dB

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• Advantages of high chipping rate
• Minimizes the time waveform peak to average
  ratio
• Each individual chip has low amplitude
  (integrated in the receiver)
• Ternary codes number of active chips per symbol
  is TBD
• Enables high degree of integration on low
  voltage CMOS
• Large code space allows selection of a number of
  good codes
• Ternary codes are best for low cross-correlation
• Time hopping codes are a possibility
• Having a large number of codes allows code
  hopping multiple access

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Peak-to-Average high chip rate vs. low chip rate
Low Chip Rate Peak
High Chip Rate Peak

• For Equal TX Output, low chipping rate has a
  higher peak power and the high chipping rate has
  a lower peak power
• Lower peak power is easier to integrate into low
  voltage semiconductor process

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SOP (Simultaneous Operating Piconets)

• Two Methods to Accommodate SOP
• Multiple Frequency Channels (FDMA)
• Within a frequency channel, use code division
  multiple access (CDMA)
• Each of possible 4 CDMA piconets uses a chipping
  rate offset
• Chipping rate offset prevents static cross
  correlation degradation

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Acquisition Preamble

• Acquisition is strictly a function of SNR, not
  bit rate or symbol rate
• For a given signal strength, the longer the
  preamble (observation time) the more robust the
  acquisition (more integration results in higher
  SNR)
• Three preamble lengths
• Mandatory medium length preamble for normal use
• Optional short preamble for higher mobility,
  high SNR scenarios
• Optional long preamble for long range, low SNR
  scenarios
• Acquisition can be either a code search
  (traditional spread spectrum)
  - or
• If SNR is high enough and channel is benign
  enough, use of a squaring loop enables
  cyclo-stationary assisted acquisition (recover
  carrier/clock frequency from collapsed spectrum
  very useful for 62.5 Kbps non-coherent OOK)

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Two Modulation, Demodulation Modes
1. Coherent demodulation at Rb 125 Kbps and
higher
Data Source
Analog SP
Digital SP
Coded Wavelets
Coded Wavelets
2. OOK (on-off keying) Non-Coherent demodulation
at Rb 62.5 Kbps
Data Source
( )2
Analog SP
Digital SP
Coded Wavelets
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Coherent Demodulation Receiver Architecture (apply
ing processing gain early reduces dynamic range
requirements)
Baseband Digital
BPF
ID
ADC
Local Code Generator
1 MHz
Local Wavelet Generator
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• OOK Non-Coherent Demodulator Receiver
  Architecture
• useful for short range, low complexity solutions
• sub-optimal solution (degrades with interference
  or multipath)

Fc31.25 KHz
OOK Decoder
BPF
( )2
LPF
ADC
Offset Frequency Correction (could be done
digitally)
gt 62.5 KHz Sample Rate
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Optional Reed-Solomon FEC
RS(38,32), GF(8), corrects 3 symbol errors good
burst error properties
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• Acquisition Characteristics
• Coherent Preamble
• TBD
• Very Robust, Long Range Acquisition
• Good in Multipath and SOP Performance
• More Overhead
• Non-Coherent Preamble
• TBD
• Less Robust, Short Range Acquisition
• Poorer in Multipath and SOP Performance
• Less Overhead

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Link Margin Tables (Coherent Demodulation)
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Link Margin Table (Non-Coherent Demodulation)
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Ranging is based upon Two Way Ranging, Time of
Arrival (TWR-TOA)
Figure 2 Two Way Ranging (TWR) transaction
enabling to estimate the round-trip
Time-OF-Flight between two asynchronous terminals
(feeding TOA-based positioning algorithms)
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Positioning from TOA
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MSC for TWR TOA/TDOA token exchange The time of
flight between the two devices is then calculated
as Tflight T1(3) - T1(0) - t/2 where the
time epochs are defined in the figure.
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Ranging Token TBD
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High Rate PHY Clock
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Channel Model PerformanceTBD
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MAC Modifications
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PHY PIB ranging attributes
Attribute Identifier Type Range Description
phyRangeClockFreq 0x04 Integer 0-10000 High Rate Ranging Clock Frequency (MHz)
phyRangeCount 0x05 Integer 0-99999 Ranging Counter Count Value
phyNferFreq 0x08 Integer 0-999999 NFER Operating Frequency (KHz)
phyNferAngle 0x09 Integer 0-99999 E-H field angle, tenths of degrees
For suggested MLME primitive and parameter
modifications, see document 15-04-0581-06-004a.
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MLME-RANGE primitive and parameters
Name Request Indication Response Confirm
MLME-RANGE 10.1.1 10.1.2 10.1.3 10.1.4
Name Type Valid Range Description
SrcID Integer Any valid DEVID as defined in TBD The device ID of the source
DestID Integer Any valid DEVID as defined in TBD The device ID of the destination
Timeout Integer As defined in TBD The time limit for completion of the ranging packet exchange.
Reason Code Integer 2 octets first two bits indicate if requrested RangeType is supported (10.1.4.2) next 11 bits indicate supported RangeTypes (0not supported, 1supported) b0,1enumerated (as per 10.1.4.2) b2 TWR TOA b3 TWR TOA DOUBLE b4 OWR TOA-A b5 OWR TOA-P b6 TWR TDOA b7 TWR TDOA DOUBLE b8 OWR TDOA-A b9 OWR TDOA-P b10 SSR b11 AOA b12 NFER b13reserved b14reserved b15reserved
RangeType Integer 0 to 10 (4 bits from octet) 0TWR TOA 1TWR TOA DOUBLE 2OWR TOA-A 3OWR TOA-P 4TWR TDOA 5TWR TDOA DOUBLE 6OWR TDOA-A 7OWR TDOA-P 8SSR 9AOA 10NFER 11 to 255reserved
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Optional Low Frequency PHY
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GPS Extension IndoorsUsing Near Field
Electromagnetic Ranging Technology

• Uses penetrating, narrow band, low frequency, low
  power signals (typically in the AM broadcast
  band, operating under Part 15 authorization).
• Indoor propagation testing confirms accuracy of
  better than 4 m at ranges up to 70 m

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GPS Extension IndoorsPrototype Hardware

• Receiver uses two orthogonal magnetic crossed
  loops and one electric antenna.
• Transmitter uses a 2 foot whip antenna.
• Operating frequency 1295 kHz

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GPS Extension IndoorsPropagation Testing

• Approximately 40 m x 60 m steel frame industrial
  building w steel stud walls located in
  Huntsville, Alabama.

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GPS Extension IndoorsPropagation Testing

• The building offers achallenging propagation
  environment complete with a corrugated metal wall
  dividing the old front half of the building from
  the new back half.
• Forty interior points (numbered rectangles)
  yielded measurements from 10 m to 70 m.

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GPS Extension IndoorsPropagation Testing

• Data taken from three points offset 10-20 m from
  the building (blue stars).

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GPS Extension IndoorsPropagation Testing

• Mean error lt 4m
• Range gt70 m (ran out of space in building!)

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Optional High Precision UWB PHY
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High Precision UWB TOA Implies Wide Bandwidth
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TBD