Desert William H' Graff President and Director of Engineering, AmericanTCB

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DesertWilliam H. GraffPresident and Director of
Engineering, AmericanTCB
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What is MIMO?
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MIMO

• From a regulatory perspective, MIMO is a
  multi-antenna version of WiFi
• All tests are identical to those currently
  required for 15.247
• In most cases, two separate chained
  transmitters operate simultaneously
• RF power listed on the Grant is the sum of both
  PA.

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Most common configuration

• 2 transmit, 3 receive (2 x 3) MIMO
• Omni directional antennas
• Resultant signal propagation is omnidirectional
• Diversity transmit/receive with a lot of Digital
  Signal Processing

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Basic MIMO Block Diagram
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MIMO and RF exposure

• No significant change to MPE procedures
• SAR reports must be more careful in identifying
  what antennas are used and at what RF power

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EMC Measurement Considerations

• Radiated emissions measurements - used standard
  techniques
• Antenna conducted emissions - use combiner
  network
• Power measurements - use power meter and spectrum
  analyzer as required by regulations
• Occupied bandwidth same for each chain
• Operating frequency same for each chain
• Theory of Operation must state that both chains
  operate on same channel at all times without
  beamforming

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WiMax

• No specific spectrum addressed in FCC rules.
• No specific channelization defined in FCC rules
  (similar to Part 24).
• Free-for-all
• Part of FCCs new Permit But Ask procedure
• Potential applicants are advised to speak to FCC
  very early in the development stage
• Follow Part 2 very closely

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WiMax Documentation Considerations

• Very important to spend a lot of time on manuals,
  operational description, etc. FCC has seen few
  WiMax devices within the 2-2.7 GHz band.
• FCCs questions reflect their caution
• Expect the time line to be long. Our experience
  would place it at minimum one month from time
  filing first filed with ATCB
• Check back with us later!
• Changes are coming!

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WiMax SAR Considerations

• Do not use 2450 MHz dipoles and mixtures for the
  new frequency range.
• Make sure your probes are calibrated for the
  center of the band of interest.
• Purchase your validation dipoles early!
• Expect a lot more detailed SAR questions

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RFID

• Can exist in many parts of the Rules.
• Very low-power devices are defined in 15.240
  within the 433.5 434.5 MHz band
• Many devices are also available in the 15.247
  spread spectrum bands
• Lots of interest in using frequency hoppers
  within the 902-928 MHz band at 1Watt
• Passive tags are not Certified.

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ZigBee

• Low-power node communication system
• Low data bandwidth
• Good for inventory control where widgets talk to
  widgets
• Data repeaters are possible.
• Not yet caught on in North America

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802.11a / DFS Testing

• Before 2004, UNII devices (802.11a) were only
  allowed within the 5150-5250, 5250-5350, and
  5725-5825 MHz bands.
• Industry petitioned for additional spectrum
  within the 5.4GHz bands.
• FCC eventually Granted and allotted 5470-5725
  band, but in order to preserve spectrum for
  military radars, DFS protection was introduced.
• DFS Dynamic Frequency Selection

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DFS Testing

• US military radars have different modulation
  characteristics from European radars.
• Therefore EU DFS testing techniques are
  considerably different from North America.
• Technical paper available from FCC database.

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DFS Implementation

• DFS testing is required now on all 802.11a
  devices which can function as an access point.
• Full DFS testing must go through FCC for
  approvals TCBs not yet permitted.
• Client-Only devices can go through TCB process,
  but the must not implement ad-hoc or
  peer-to-peer mode within the 5GHz band.

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DFS and existing products

• Non-DFS Class II PC approvals completely cease in
  July 2007.
• Only non-DFS devices which never use the DFS
  bands of 5250-5350 and 5470-5725 MHz can seek
  approval
• DFS can be added to a non-DFS device using the
  Class II PC process. This assumes there is no
  hardware changes and DFS is simply a software
  upgrade
• No field upgrades allowed.

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Permit-But-Ask ProcedureNew! as of November,
2006

• FCC has initiated a new procedure for
  troublesome filings and new technology. Prior
  to any request for Certification, a TCB must
  request guidance from FCC on specific items to
  look for before granting Certification.
• Specifically aimed (so far) at 15.239 personal FM
  transmitters, WiMax devices and 3.5/4G
  cellphones.
• See FCC Memo to TCBs.

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Contact Information

• William H. Graff
• President and Director of Engineering
• AmericanTCB, Inc.
• 6731 Whittier Ave.
• McLean, VA 22101
• mailto whgraff_at_ATCB.com
• Corporate Phone [phone]
• Corporate FAX [phone]
• Direct Mobile [phone]
• SKYPE whgraff