FCC Part 15 rules didn't prohibit the use of smart antenna technology in unlicensed wireless systems, but they did limit the effective radiated power in each of the beams from the smart antenna. Under new rules approved by the FCC last week, systems using smart antennas will be able to use higher power levels in each beam. From what I can gather from the news release, because the beams from the smart antenna are directional and don't combine, they are not expected to cause increased interference over what would be created by point-to-point links using a single beam dumb antennas under the previous rules.
Technical details in the FCC news release FCC Changes Rules to Promote Use of Unlicensed Broadband Service in Rural Areas were limited, but indicated new rules would facilitate deployment of next generation Bluetooth wireless devices that operate at up to three times the data rate of current devices.
When the Report and Order is published, I'll have more information in a future RF Report.
