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Project IEEE P802.15 Working Group for Wireless
Personal Area Networks (WPANs) Submission Title
Recommendations of the Range Issue
Subcommittee Date Submitted September
2004 Source Frederick Martin, Motorola, Inc.,
Colin Lanzl, Aware, Inc., Paul Gorday, Motorola,
Inc., Rick Roberts, Harris Corporation, Kai
Siwiak, TimeDerivative, Inc. Contact F. Martin,
Motorola, Inc., 8000 W. Sunrise Blvd.
Plantation, FL 33322 Voice 1 954-723-6395, FAX
1 954-723-3712, E-Mail f.martin_at_motorola.com Re
Range Issue Sub-Committee Abstract A model
and basis of comparison is proposed for comparing
range performance of the baseline 802.15.4 PHY
layer with proposals for 802.15.4a. Purpose Tutor
ial information on capabilities of current 15.4
hardware. 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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Sub-Committee Charter
In response to the 802.15.4a PAR, clause 12,
Scope of Proposed Project (document
15-04-0048-01-004a), this subcommittee's scope is
to study the range implications of 802.15.4
devices and how we might ask the 802.15.4a
proposers to show at least an enhanced range
mode.
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The issue
802.15.4 bands 250 kbit/s _at_ 2400 MHz
(worldwide) 40 kbit/s _at_ 900 MHz (North
America) 20 kbit/s _at_ 868 MHz (Europe) Power
typical 0 dBm maximum Regulatory max (100 mW
Europe, 1 W US !!) Antenna not
specified Receiver sensitivity not
specified Result typical indoor range may be
10 to 30 m maximum outdoor range may be several
km !!!
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The Search for Guidance (2)
802.15.4 PAR Purpose To provide a standard for
ultra low complexity, ultra low cost, ultra low
power consumption and low data rate wireless
connectivity among inexpensive devices. The raw
data rate will be high enough (maximum of 200kbs)
to satisfy a set of simple needs such as
interactive toys, but scaleable down to the needs
of sensor and automation needs (10kbps or below)
for wireless communications. 802.15.4 PAR --
Scope This project will define the PHY and MAC
specifications for low data rate wireless
connectivity with fixed, portable and moving
devices with no battery or very limited battery
consumption requirements typically operating in
the Personal Operating Space (POS) of 10 meters
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The Search for Guidance (2)
802.15.4a PAR Scope This project will define
an alternative PHY clause for a data
communication standard with precision ranging,
extended range, enhanced robustness and mobility
amendment to standard 802.15.4 (18a). 802.15.4a
PAR -- Purpose To provide a standard for a low
complexity, low cost, low power consumption
alternate PHY for 802.15.4 (comparable to the
goals for 802.15.4). The precision ranging
capability will be accurate enough, several
centimeters or more, and the range, robustness
and mobility improved enough, to satisfy an
evolutionary set of industrial and consumer needs
for WPAN communications. The project will address
the requirements to support sensor, control,
logistic and peripheral networks in multiple
compliant co-located systems and also coexistence
(18b).
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The Philosophy behind the Proposed Solution
In the spirit of the 802.15.4 PAR, compare 4A
proposals with typical low cost, low power
802.15.4a implementations Transmit Power 6
dBm (900 MHz), 0 dBm (2400 MHz) Receive
Sensitivity -95 dBm (900 MHz), -90 dBm (2400
MHz) isotropic antenna See specs for Freescale
MC13192 CompXs CX1540 Atmel
AT86RF210 Chipcon -- CC2420
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Indoor Path Model Comparison
Colin Lanzl clanzl_at_ieee.org Kai Siwiak
k.siwiak_at_ieee.org Paul Gorday
paul.gorday_at_motorola.com
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Two-Breakpoint Model with Recommended Parameters

• PL(d ) -10logc/(4pdfm)2 1-exp(-(dt1
  /d)g1-2)1-exp(-(dt2/d)?2- ?1,
• where
• PL pathloss, dB
• d distance between transmitter and receiver
• fm geometric mean of transmitted frequency
  band
• g1 propagation constant after first
  breakpoint (3.7)
• g2 propagation constant after second
  breakpoint (10.5)
• c velocity of propagation
• dt1 first breakpoint distance from
  transmitter (5 meters)
• dt2 second breakpoint distance from
  transmitter (30 meters).

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Loss-per-Meter Indoor Model with Recommended
Parameters

• PL(d ) -10logc/(4pdfm)2 ?d,
• where
• PL pathloss, dB
• d distance between transmitter and receiver
• fm geometric mean of transmitted frequency
  band
• ? loss-per-meter parameter (0.60dB per
  meter)
• c velocity of propagation.

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Comparison of Indoor Path Loss Models
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Path Loss References
1 K. Siwiak, A. Petroff, A Path Link Model for
Ultra Wide Band Pulse Transmissions, Proc.
IEEE Vehicular Techonlogy Conference, Spring
2001, vol. 2, pp. 1173-1175. 2 D.
Devasirvatham, et al., Multi-Frequency Radiowave
Propagation Measurements in the Portable
Radio Environment, IEEE International Conference
on Communications, April 1990, vol. 4, pp.
1334-1340. 3 K. Marquess, Physical Model
Sub-Group Discussion and Questions, Submission
to IEEE 802.15 Working Group for Wireless
Personal Area Networks, Doc. IEEE 802.15/138r0,
Nov. 1999. 4 K. Siwiak, Basic
Propagation Attenuation Model Suitable for UWB
and Narrow Band Signals, IEEE P802.15
Working Group for Wireless Personal Area
Networks, Doc. IEEE P802.15-04/0408r1,
August 2004. 5 D. Cassioli, et al., The
Ultra-Wide Bandwidth Indoor Channel From
Statistical Model to Simulations, IEEE
Journal on Selected Areas in Communications, vol.
20, no. 6, Aug. 2002. 6 S. Ghassemzadeh, et
al., A Statistical Path Loss Model for In-Home
UWB Channels, IEEE Conference on Ultra
Wideband Systems and Technologies, May 2002, pp.
59-64. 7 L. Rusch, et al., Characterization
of UWB Propagation from 2 to 8 GHz in a
Residential Environment,
http//www.intel.com/technology/ultrawideband/pres
_tech.htm.
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Flat Fading Margin for 802.15.4

• Assume that both 802.15.4 PHYs undergo flat
  Rayleigh fading
• Chip pulse length is relatively long compared to
  RMS delay spread (pulse length 1
  ?s at 2.4 GHz, 3.3 ?s at 900 MHz, 6.7 ?s at 868
  MHz)
• Simple 2.4 GHz PHY implementation (no equalizer
  or rake) shows multipath performance similar to
  flat fading for RMS delay spreads up to 300-400
  ns (doc. 337r0). 868/915 MHz PHY would tolerate
  more.
• Diversity methods (antenna, rake, mesh network,
  etc.) would improve performance relative to flat
  Rayleigh fading, but are not considered here.
• Rayleigh fading margin vs. desired reliability
• 10 dB margin gives 90 probability of exceeding
  desired level
• 13 dB margin gives 95 probability of exceeding
  desired level
• Typical PHY sensitivity (1 PER, 20-byte PSDU)
• 2.4 GHz PHY -90 dBm
• 868/915 MHz PHY -95 dBm
• Typical performance is 3-5 dB better than
  802.15.4 PHY spec.

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Baseline performance of 802.15.4
900 MHz 2400 MHz
Transmit Power (dBm) 6 0
RX Sensitivity (dBm) -95 -90
Fading Margin (dB) 10 10
Link Budget (dB) 91 80
Range (m) (2 breakpoint model) 43 25
Range (m) (Loss per meter model) 44 22
INPUTS
CALCULATED VALUES
LINK BUDGET TX POWER RX SENSITIVITY FADING
MARGIN
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Sub-Committee Recommendations

• Compare proposals with typical low-cost,
  low-power implementations of 802.15.4. See slide
  6.
• 2. Apply either the 2 breakpoint model (slide 8)
  or the loss per meter model (slide 9) as a basis
  for comparison.
• 3. Adopt 10 dB as the flat fading margin for the
  802.15.4 baseline per slide 12.
• 4. Leave to proposers the responsibility for
  specifying and justifying fading margin and
  receiver performance assumptions for their
  proposals.

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Motion ???