WIMAX Forum certification in the 2.5GHz frequency band has gathered apace in recent weeks with more big-name vendors being welcomed into the fold: Alcatel-Lucent and NEC, along with GCT Semiconductor and Telsima, have each had 802.16e products rubber-stamped by the WiMAX Forum over the last month.

And it was only three months ago that the first batch of 2.5GHz certified products were announced at the WiMAX Forum Global Congress in Amsterdam: Alvarion, Motorola, Samsung, Intel, Sequans, Airspan, Beceem and Zyxel each had 802.16e products certified using Wave 2 technology (MIMO and smart antenna).

With Wave 2 testing currently underway in six testing labs around the world, it’s clear that momentum is picking up for mobile WiMAX product certification at 2.5GHz. The WiMAX Forum further predicts there will be more than 100 mobile certified products – across all profiles – by the end of this year, rising to more than 1,000 by the end of 2011.

And if the experience of the WiMAX camp is anything to go by, it seems reasonable to believe that the LTE community won’t be able to deliver on certified products (that are truly interoperable) anytime soon. It was as far back as December 2005 when the WiMAX Forum agreed on the IEEE 802.16e standard, so there has needed to be nearly three years of testing until the arrival of the first certified Mobile WiMAX products. Work on 3GPP Release 8, which defines the LTE air interface, has still to be completed.

But despite all the focus on 2.5GHz, principally because of the ambitious mobile WiMAX plans set out by Sprint Nextel and Clearwire in the US, it is in the 3.5GHz frequency band where most of the WiMAX action is in terms of operator numbers. According to the World Cellular Information Service (WCIS), which is provided by Informa Telecoms & Media, there are over 60 commercial WiMAX deployments in this frequency.

And with the prospect of more and more regulators allowing 3.5GHz to be used for mobile services, operators in this frequency band – who want to pursue a multi-vendor strategy – are no doubt restless for 3.5GHz mobile WiMAX certification to begin as soon as possible.

The good news is that the WiMAX Forum has said that 3.5GHz certification for mobile WiMAX in three profiles – based on channel bandwidths of 5MHz, 7MHz and 10MHz – will start in earnest before the end of this year.

Yet certification, although clearly important, may not necessarily be sufficient in itself to achieve what is the Holy Grail for most operators: guarantees on a fully interoperable end-to-end network using different suppliers’ kit, which avoids vendor lock-ins and drives down prices through competition.

While there is 802.16d certified kit available in the marketplace today, for example, some 3.5GHz WiMAX operators have expressed disappointment that there has not been a higher level of interoperability between different vendors’ fixed WiMAX base stations and CPE in this frequency.

The WiMAX camp, as with the LTE community, has the challenge of producing certified equipment that avoids the need for lengthy (and probably expensive) periods of systems integration. The WiMAX community nevertheless has the comfort of knowing, at least for the time being, that it has a distinct time-to-market advantage over rival LTE in getting certified/interoperable mobile products out into the marketplace.