For most of the world, WiMAX resides in the 3.5 GHz block of spectrum, but in the U.S., it encompasses the 2.3 and 2.5 GHz frequencies. The most famous WiMAX deployments -- those by Clearwire and Sprint -- are all licensed in the 2.5 GHz block of spectrum. But there have been very few deployments in the 2.3 GHz frequency. Even though it has been allocated to Wireless Communication Services (WCS) since 1997, buildouts in that range have been very limited because of a major conflict with Sirius and XM satellite radio.

Satellite radio employs thousands of terrestrial repeaters which were FCC compliant, but due to uncertainty in technical requirements in FCC regulation, were found in 2006 to have serious potential interference problems in 2.3 GHz WiMAX transmissions. Companies such as AT&T, BellSouth, Comcast, Sprint, and NextWave had 2007 construction deadlines on their 2.3 GHz licenses, which the FCC then pushed back to July 2010 after hearings with the WCS Coalition and Sirius and XM.

Following the hearings, the FCC said, "We find that WCS licensees have demonstrated that they face factors beyond their control that have limited their options in providing service, but that new technology solutions may be available in the near future. We agree with the WCS Coalition that limited deployment attempts using available equipment have been marred by technical problems or proved to be economically infeasible."

Today, just short of one year ahead of the latest 2.3 GHz construction deadline, the WiMAX Forum has announced that validation testing has begun on the profile in the 5/10 MHz and 8.75 MHz channels, and that the first products certified for use in that frequency should be ready as early as next quarter.

Additionally, this block of spectrum is used in 29 commercial WiMAX deployments worldwide in countries such as Malaysia, Indonesia, Singapore, and Georgia. The WiMAX Forum today said that 13 companies have submitted base station and subscriber station equipment to be tested and validated.

Ed Agis, co-chair of the WiMAX Forum Certification Working Group, said, "At the start of the certification program, it took about nine months to get the first batch of test cases complete. Now it only takes two to three months to validate the test cases before we start certifying devices...Certification profiles for 2.3 GHz also pave the way for WiMAX Forum Certified tri-band devices in 2010 which will increase the opportunities for true global roaming across networks in the 2.3, 2.5, and 3.5 GHz spectrum bands which make up a global WiMAX footprint today."