Washington Laboratories (301) web: Lindbergh Dr. Gaithersburg, MD Desert William H. Graff President and Director of Engineering, AmericanTCB

What is MIMO?

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

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

Basic MIMO Block Diagram

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

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

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

WiMax Documentation Considerations Very important to spend a lot of time on manuals, operational description, etc. FCC has seen few WiMax devices within the GHz band. FCC’s 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!

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

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

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

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

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.

DFS Implementation DFS testing is required now on all a 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.

DFS and existing products Non-DFS Class II PC approvals completely cease in July Only non-DFS devices which never use the DFS bands of and 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.

Permit-But-Ask Procedure New! 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 personal FM transmitters, WiMax devices and 3.5/4G cellphones. See FCC Memo to TCBs.

Contact Information William H. Graff President and Director of Engineering AmericanTCB, Inc Whittier Ave. McLean, VA mailto: Corporate Phone: (703) Corporate FAX: (703) Direct Mobile: SKYPE: whgraff