More tinkering on the way for wireless ISP spectrum

Wireless Internet service providers (WISPs) in the U.S. that face growing Wi-Fi interference are excited about a radio band that was set aside for them on Friday, but industry and government still need to thrash out some key details.

Under rules that became effective Friday, the U.S. Federal Communications Commission (FCC) allows WISPs to use frequencies between 3650MHz and 3700MHz, a band that is already utilized by satellite Earth stations and radar stations on both coasts but largely unused in the middle of the country. There, many sparsely populated areas have not been reached by DSL (digital subscriber line) or cable Internet services and have turned to WISPs, generally small operators that can't afford to license spectrum.

The band is sizable, big enough for broadband services from two or more WISPs in any given area, according to industry participants.

Even though the rules are effective now, apart from a few minor details that need separate approval, WISPs can't use the spectrum yet because no devices have yet been approved for the use, according to a senior FCC official. In addition, the agency was due to receive petitions for reconsideration on Friday, in which industry and the public could ask for changes in the rules. Considering and implementing such changes typically takes months, the official said.

How the final rules shape up has implications for the radio environment a provider will face and what kind of equipment becomes available. Equipment vendors and service providers are looking for greater clarity from the FCC because they see a major opportunity at stake: If the rules are crafted the way some would like to see them, WISPs may be able to use the emerging WiMax wireless broadband technology and reap the benefits of volume economics.

The WiMax Forum, which will certify WiMax equipment for specific radio bands, has no plans on the table for certification testing in that spectrum, said Aditya Agrawal, co-chair of its Certification Working Group. But the band is nearby the 3.4GHz-to-3.6GHz spectrum that will be used by the first approved WiMax products, expected late this year. Certification in the 3650 band could be added later if there is enough demand, he said.

Most WISPs use unlicensed spectrum, especially the band around 2.4GHz that is also used by IEEE 802.11b and 802.11g Wi-Fi equipment. Many use Wi-Fi technology themselves, reaching their subscribers over long distances by using special outdoor antennas to extend range. But the phenomenal popularity of low-priced Wi-Fi access points among consumers has caused headaches.

"My WISP is located in [radio frequency] hell," Michael Anderson, co-owner of PDQLink Wireless, in North Aurora, Illinois, wrote in an e-mail interview. "I drove home from one of my towers a few weeks ago. ... the distance was less than eight miles. My laptop picked up over 404 access points." The radio waves produced by those home access points can go beyond the walls of the house and interfere with a WISP's longer range transmission, he said. Anderson also is chairman of Part-15.org, an group of WISPs.

Last Mile Wireless LLC serves more than 300 local residences and businesses in Preston, Idaho, where DSL and cable aren't available and dialup speeds are slow, according to TJ Burbank, a partner in the company. The operator's 2.4GHz long-range, directional Wi-Fi service runs into interference from another WISP's 2.4GHz network, and Burbank is looking forward to getting access to more unlicensed spectrum and being able to use WiMax.