Bluetooth wireless technology, issues, concerns

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Bluetooth wireless technology, issues, concerns

• MOHCA Second National Summit on Electromagnetic
  Compatibility
• Bill Saltzstein
• Code Blue Communications, Inc.
• March 26, 2003

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Bluetooth 802.11b

• Bluetooth Cable replacement
• Designed for highly mobile, low power,
  (relatively) short range, low cost
• Primary target cell phones, PDAs, personal
  devices
• Profiles for intended uses Serial, Dial-up,
  Printer, LAN, Car
• Ad-hoc networks low to no administration
• 802.11b LAN replacement
• Designed for relatively stationary, relatively
  high-speed devices
• Primary target PCs, office and factory devices
• TCP/IP structured networks with roaming cellular
  support
• Seeing HUGE uptake including hotspots

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Wireless technology use models
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Bluetooth characteristics - 1

• 10 meter, 1 Mbps raw 720kbps payload
• 2.4 GHz, 79 channels, 1MHz bandwidth, frequency
  hopping spread spectrum, GKFS modulation
• 1600 hops per second
• 3 power classes all quite low
• Class 1 100mW (20 dBm) power control mandatory,
  100m
• Class 2 2.5mW (4 dBm) optional power control,
  20m
• Class 3 1mW (0dBm) most devices, 10m

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Bluetooth characteristics - 2

• Multiple error correction schemes
• Forward Error Correction
• Packet retransmission (ACL data link only)
• 8 active devices, 1 master per piconet
• SAFER 128 bit cipher used for encryption and
  authentication (security is optional)
• ACL link for data, SCO for voice

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Coexistence802.11b and Bluetooth

• High FUD factor (Fear, Uncertainty, Doubt) by
  certain writers, probably due to Bluetooth hype
• Neither technology will let bad data through to
  the application or user (except Bluetooth SCO
  audio)
• Errors detected and corrected (by whatever means)
  result in
• Degradation of throughput
• Increased latency
• Graceful degradation in all cases

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Coexistence on the ISM band
Note US representation 802.11b is different OUS
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Real test results (summary)

• No errors
• Degradation never gt 15 with FH systems
• 2.4GHz direct sequence is perhaps the biggest
  interference source
• Effect of 802.11b greater with Class 3 powered
  Bluetooth
• Effect of Bluetooth greater with Class 1
  Bluetooth
• 802.11b (DS) is significantly worse than 802.11
  (FH) near field effects with DS are an issue
• Microwave ovens arent a big issue for Bluetooth
• Real world performance shows little issue with gt2
  meter separation

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The future of coexistence

• IEEE 802.15.2 and SIG have agreed on two methods
  for coexistence to be included in Bluetooth 1.2
  to be released this year
• Non-collaborative Adaptive Frequency Hopping
  (AFH) enabled by FCC change allowing fewer FH
  channels (down to 15)
• Collaborative time and/or frequency sharing
• Changes allow for coexistent Access Points and
  other high powered simultaneous devices

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Bluetooth medical demonstrations ad-hoc testing

• SpO2 demonstration
• Siemens arrhythmia monitor testing
• Bluetooth and the Bovie

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Bluetooth SpO2 demo
No observedeffects
Palm Tungsten T, Nonin iPod, connectBlue Serial
Port Adapter (Class 3) For demonstration only
not for patient use
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Bluetooth w/ Siemens monitor
Siemens SC 6802XL, Belkin Class 1 USB Bluetooth
adapter
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Bluetooth w/ Siemens monitor

• Class 1 (20 dBm) Bluetooth
• Nominal Bluetooth data rate 600 kbps
• Bluetooth nodes separated by 220 ft for full
  power
• No observed effects
• Arrhythmia detection
• Heart rate
• Waveform
• User interface
• Bluetooth data rate reduced in some
  configurations due to antenna interactions with
  cabling
• Thank you to Siemens Medical for the use of their
  SC 6802XL monitor!

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Bluetooth and the Bovie
No dropouts in 4 ch.continuous waveformduring
120W Bovieusage in coag. Mode No observed
effects
GSI/Lumonics recorder prototype, Anycom CF card
(Class 3), JJ Ethicon ESU
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Contact and information
Bill Saltzstein Code Blue Communications,
Inc.23436 NE 140th StWoodinville, WA
98072 [phone] phone[phone]
FAX[phone] cell billsalt_at_codebluecomm
unications.comhttp//www.codebluecommunications.c
om
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IEEE 802.xx

• 802.3 Local Area Networking - Ethernet
• 802.11 Wireless Local Area Networking
• Blank or FH frequency hopping like Bluetooth
• b Direct Sequence, uses 3 bands out of 11 in US
  (WiFi)
• a new 5.2 GHz. OFDM, 54 Mb/s
• g 54 Mb/s in ISM band
• x security, authentication (128 bit WEP, TKIP,
  etc.)
• 802.15 Personal Area Networking
• .1 low power, low cost Personal Area Network
  (Bluetooth)
• .2 coexistence
• .3 WPAN-HR (Wireless PAN High Rate)
• .4 ZigBee (industrial sensors low data rate,
  low duty cycle, very low power)

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Summary

• Bluetooth wireless Technology (IEEE 802.15.1) is
  becoming the wireless standard for highly-mobile,
  small, battery powered devices such as PDAs and
  cellular phones. It has seen a high level of
  interest from Medical Device manufacturers for
  use in devices with these attributes, or devices
  that would communicate with them.
• This presentation briefly describes the
  electromagnetic characteristics of Bluetooth
  technology, its coexistence and interference with
  other RF communication standards, and its
  interference potential for medical devices.