History of WLANs in the Unlicensed Bands George Mason University Law School Conference Information E

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History of WLANs in the Unlicensed Bands
George Mason University Law School
ConferenceInformation Economy ProjectArlington
VAApril 4, 2008Dr. Kevin J. Negus Al Petrick
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Outline

• Wireless Local Area NetworksToday!
• Major Historical Landmarks
• FCC First Report and Order on 81-413
• Early Products
• FCC Docket no. 89-354
• HomeRF Early Days
• UNII Process
• High Rate Direct Sequence
• Wideband Frequency Hopping
• Wi-Fi Beats HomeRF
• Digital Modulation
• IEEE 802.11n
• Conclusion

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WLAN Today

• Wi-Fi market
• 450Munits 2008..1Billion Units 2010
• VoIP and Streaming video application
• Digital home!
• Dual mode cellular/handsets
• 802.11g 54Mb/s
• 802.11n 100Mb/s 600Mb/s
• 802.11g access points - 49
• 802.11n access points 100

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Major Historical Landmarks

• Original rules for the unlicensed operation in
  the ISM bands
• Early revisions of Frequency Hopping bandwidth
  and Direct Sequence Processing Gain
• Harris 8-chip MBOK permissiable under direct
  sequence rules
• Allow wider frequency hopping bandwidth at 2.4GHz
• Digital modulation amendment to the 2.4GHz rules

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FCC First Report and Order on 81-413

• 1985 FCC authorizes spread spectrum in the
  902-928MHz, 2400-2483MHz, and 5725-5875MHz bands
  for unlicensed use
• Industrial Scientific Medical (ISM) FCC
  Part 15 rules
• Direct Sequence, Frequency Hopping
• Direct sequence channels 500kHz (6dB bandwidth)
• Frequency hopping 75 non-overlaping channels
  25kHz BW
• 1 watt maximum peak output power
• Must co-exist with interference in the bands

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Early Products - WLAN

• 1988 Telesys introduces 1st WLAN system
• DSSS 900Mhz
• 1989 PROXIM introduces Rangelan900
• DSSS 900MHz
• 220kb/s
• Applications
• Warehouse and Inventory tracking systems

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FCC Docket no. 89-354

• New Report and Order on Spread Spectrum Devices
• Direct sequence (DSSS)
• Initial docket suggested 127 chips PG21dB
• Would limit 802.11 QPSK to 500kb/s using entire
  band
• Adopted 10dB of process gain
• Frequency Hopping (FHSS)
• FCC expanded hop channel bandwidth to 1MHz
• Allowed the use of directional antennas
• 1990 IEEE 802.11 begins development on a
  standard for DSSS and FHSS WLAN system

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HomeRF Early Days

• Formed in 1996
• Intel, Microsoft, HP, Compaq and IBM
• HomeRF goal
• Low-cost consumer WLAN
• Integrate toll-quality voice and data
• Home PC as network hub
• Intially based on 802.11 FHSS PHY
• Adopted a hybrid of 802.11 and DECT
• 1998 HomeRF merges with WLIF
• Compatible with Proxims silicon
• Proxims 2-chip solution supported both HomeRF
  and 802.11 FHSS
• Compact form factors lt100

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U-NII Process

• 1997 FCC Report and Order
• ET Docket No.96-102
• Created a new set of rules under 15.401-407
• 5.125-5.35GHz and 5.725-5.825
• Enabled the use of HIPERLAN
• Restricted a system to maximum total power and
  maximum power density
• Required a 20MHz bandwidth to reach maximum power
  in a 100MHz segment
• 1998 January IEEE 802.11a begins standards for
  5GHz WLANs
• follows U-NII rules
• Modulation, OFDM54Mb/s data rates

OFDM Sub Carriers for 802.11a
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High Rate Direct Sequence

• 1997 - Harris MBOK 8-chip achieves FCC approval
• 802.11b selects CCK a modulation similar to MBOK
• 2400, 2483Mhz, 20MHz channels
• 3 non-overlapping 20MHz channels
• Data rates 1.2.5.5 and 11Mb/s
• Harris PRISM 1st 802.11b chipset
• 1999 WECA (now Wi-Fi Alliance)
• Multi-vendor Interoperability certification

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Wideband Frequency Hopping

• 1999 June
• ET Docket No. 99-231
• FCC adopts HRFWG proposal
• Expands channel BW to 5MHz
• Enables FHSS WLANs to achieve 10Mb/s data rate
• 1MHz channels for Voice
• 5MHz channels for Data
• Comparable performance to 802.11b

HomeRF Channelization
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Wi-Fi Beats HomeRF

• Race between Wi-Fi and HomeRF
• 1998 802.11b standard was positioned to enable
  products to achieve 10Mb/s in 2.4GHz band .
  (Ethernet speeds)
• HRFWG (HomeRF Working Group)
• Needed to have similar performance as 802.11b in
  a similar timeframe
• Nov 1998 HRFWG submits proposal to increase hop
  channel bandwidth to 5MHz
• The major of the equipment manufactures had
  vested interest in 802.11b and WECA
• 2000 September FCC approved HRFWG proposal
• Due to competitive pressures 802.11b and WECA
  succeeded in delaying HRFWG
• 2002 HRFWG collapsed

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Digital Modulation

• Wi-LAN initiated 1st petition to the FCC
• Use OFDM in the 2.4GHz band
• FCC viewed OFDM as not spreading
• Texas Instruments claimed its PBCC was compliant
  with direct sequence rules
• FCC was open to digital modulation techniques
• Power lt1mW and not exceed existing power spectral
  density of 8dBm in 3kHz BW
• 2001 May FCC allows digital modulation OFDM at
  2.4GHz
• 2000 IEEE 802.11g begins developing higher rates
  54Mb/s at 2.4GHz
• Modulations considered PBCC, Sequence Code
  Modulation, CCK-OFDM
• IEEE 802.11g adopted 802.11a OFDM in the 2.4GHz
  band in 2001
• Atheros, Broadcom, Intel and Marvell emerge as
  semiconductor industry leaders

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IEEE 802.n

• 2003 802.11n project started
• MIMO technology
• Spatial Division Multiplexing
• OFDM, 100Mb/s 600Mb/s
• 2.4GHz, 5GHz bands
• 20/40MHz channels
• Backward compatible with 802.11b/g
• Airgo Networks and Atheros
• 1st 802.11n MIMO radio in 2005
• Wi-Fi Alliance Certification
• 802.11 Draft Pre-N 2.0, May 2007
• 802.11n to complete standard 2009
• 802.11 VHT-SG started March 2007
• 6GHz and 60GHz bands
• OFMD
• Gigabit data rates gt1Gb/s

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Conclusion

• Less is more when setting rules for unlicensed
  spectrum access
• Focus on transmitters not receivers
• 802.11n is the first step to bringing spatial
  processing to reality in the unlicensed spectrum
  
• Special thanks to the FCC and to Equipment
  providers for the success of WLAN Market and
  making consumers

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Thank you !

• Dr. Kevin J. Negus
• Email kevin_at_tctwest.net
• Phone [phone]

Al Petrick Email al_at_jpasoc.com Phone
1-321-235-3269