Proprietary vs' StandardsBased Wireless Solutions for AMR Applications

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Proprietary vs. Standards-Based Wireless
Solutions for AMR Applications
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Why AMR?

• AMR is a special case of wireless sensors.
• Water AMR has the most restrictive requirements
• Last year, 10 million wireless AMR units were
  installed worldwide
• Active Development
• Most AMR companies are working on second
  generation technology

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Water AMR
Electromechanical Register Interface
PCB Antenna
Wireless Link
Battery Powered
Microcontroller
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Typical Environment

• Steel Pit
• Buried underground
• Iron Lid
• Submerged in water
• -20 to 70 deg C
• Separation depends on lot size

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Typical Architecture

• First generation systems are drive by
• One way bubble-up
• Next generation systems will be two-way
• Moving toward fixed network

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Battery Requirements

• 10 to 15 year battery life
• Typically LiSOCl-
• Replacement is difficult and therefore
  undesirable
• lt125uA continuous

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Frequency Bands
900MHz
2.4GHz

• World-wide band
• Used in most standards
• Resonant frequency of H2O
• Many sources of interference
• Bluetooth
• WiFI
• Cordless phones
• Zigbee

• 2x range over 2.4 GHz for equal link budget
• 26 MHz bandwidth
• Frequency diversity ineffective

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Modulation
DSSS
FHSS
Frequency Static

• Jammer rejection due to spread gain
• Single frequency
• Fast sync time
• Most complicated
• Highest power

• Jammer rejection due to hopping
• Slower sync time
• Simple design FSK radio with special protocol
• Power is comparable with frequency static

• Single frequency
• ASK/OOK or FSK typically
• DTS for higher output power
• Fastest sync time
• Lowest power
• Simplest design

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Problem with Mesh
Collector
Nodes closest to collector have shorter battery
life than nodes furthest from collector
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Radio Requirements

• gt110dB link budget for 100 foot range
• lt100kbit/sec data rate
• Fast wake-up time
• Must be able to sleep most of the time

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Wireless Standards
802.11 a(b)
Bluetooth
ZigBee
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802.11a(b)

• 94dB link budget
• High power consumption
• DSSS complex modulation
• High data rate
• Low power microcontrollers cannot keep up
• 2.4 GHz operation
• Significantly attenuated by water
• Not good for submerged or body worn devices

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BlueTooth

• 85dB link budget
• High power consumption
• Very long sync time (measured in seconds)
• FHSS modulation
• 2.4 GHz operation
• Significantly attenuated by water
• Not good for submerged or body worn devices

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ZigBee
Specifications by band
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Proprietary
XEMICS Chipcon Nordic Micrel Ti FreeScale

• Wireless IC Vendors
• Contract Engineering Firms
• Other Module Companies

Aerocomm, Maxstream, Linx Technologies, RF
Monolithics, Radiometrix
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Make vs. Buy

• Wi.232DTS solution profitable in 8 months
• Chipset solution profitable in 17 months

• Wi.232DTS 23 month profit is 5.4M
• Chipset 23 month profit is 1.5M

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Wi.232DTS

• True UART to RF solution
• Small - .75 in square
• 114-121dB link budget
• Low voltage operation
• Protocol engine with CSMA
• Supports automated assembly
• True peer-to-peer networking
• No master required
• Footprint compatible with Wi.232FHSS-25
  Wi.M900X/T

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Comparisons
Performance
Cost
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Conclusions

• 2.4 GHz is inappropriate for water AMR
  applications
• DSSS or DTS are better than FHSS due to short
  wake-up time
• Proprietary solutions fit the requirements of AMR
  applications better than standards based
  solutions
• Modular proprietary solutions are less expensive
  and allow faster time to market than chipset
  level solutions

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Additional Reading
Available at www.onworld.com Wireless AMR
Submetering A market dynamics study on fixed
wireless technologies.
Available at www.radiotronix.com Wi.232 vs.
Chipset solutions - Make vs. Buy
presentation Wi.232 vs. WiFi - Wi.232DTS vs.
WiFi for Embedded Applications Wi.232 vs.
Zigbee -Wi.232DTS vs. Zigbee Basic wireless
concepts -Wireless 101 white papers