Smart antennas use, OFDMA and specifically the spectral efficiency of OFDMA are routinely offered as the advantages of a mobile WiMAX. The true competitive strengths of WiMAX may prove to be elsewhere.

Intelligent antennas are on the road map of every major standard not just WiMAX, including those from the 3GPP (WCDMA) and 3GPP2 (CDMA) and the emerging 802.20 standard. Existing mobile carriers are unlikely to deploy intelligent antennas with a new air interface initially for coverage or capacity since these carriers already possess substantial tower assets and existing mobile carriers generally scale capacity on new services and/or air interfaces gradually to meet initial and limited demand for those services. Thus WiMAX may have a time advantage in implementation of intelligent antennas but that gain will be neutralized by mobile carriers themselves.

OFDMA is also on the road map of virtually every major standard, including those mentioned above. 3GPP2, perhaps through the standardization of FLASH-OFDM, stands to be the first group to offer a mobile, deployment ready version of OFDMA. 3GPP will follow and 802.20 could ratify an OFDMA standard by late 2006.

Equally important are the benefits of OFDMA, especially when pertaining to spectral efficiency in a wide area, multi-cellular, mobile environment, remain unproven regarding the implementation which WiMAX purveyors and most others will use.

The advantage may exist from use of the air interface but the level of improvement, especially in a challenging mobile environment, may not be as great as many are expecting. Likewise, performance may vary substantially according to implementation and performance of the MAC level, which governs how the radio spectrum is employed and which is rarely considered in RF simulations. Ultimately more testing is required now that 802.16e has been ratified and vendors are working on implementing the standard.

So what are the advantages of mobile WiMAX at the current time? WiMAX is the first truly open mobile standard (802.16e). It is governed by the IEEE's fair licensing practices and participation in the group is open and democratic compared to other groups. This is in fact revolutionary as 3GPP and 3GPP2 are ultimately consortiums and its implications are wide. This open process should lead to greater innovation and hence a better performance when moving forward and also potentially lower intellectual property licensing fees and provide for a quicker rate of change compared to that of existing mobile technologies.

A lack of history within the mobile industry is also an advantage for WiMAX vendors. For the most part, and in contrast to CDMA/GSM/WCDMA vendors, key WiMAX equipment vendors lack a mobile product line to protect. They must push the envelope on technology and move forward as they cannot rely on a steady stream of existing GSM, WCDMA, or CDMA mobile contracts. In other words, WiMAX proponents benefit from disrupting the status quo and their survival may depend on it.

WiMAX is also the first major mobile standard to offer all IP as a standard feature set. 3GPP will get there in subsequent releases but it still employs a complicated and ultimately expensive core network. Major mobile carriers, who are often also wireline or even cable operators, will seek to consolidate their core networks under IP. Doing so offers cost advantages, the ability to offer multiple services over a single platform, reductions in operating and capital expenditures, rapid application development and often a competitive edge.

In summary, we need to look beyond RF performance criteria alone when evaluating the relative merits of mobile WiMAX vs. future incarnations of existing mobile technologies due to lack of real world data and the existence of other often ignored criteria.

GSM won the 2G mobile war despite offering inferior capacity figures due to strengths in other quadrants of the competitive matrix and we can not accurately gauge the performance that FLASH-OFDM, UMTS or 802.16e air interfaces will offer in 2008 or 2009 when mobile WiMAX gear is certified and ready to ship today.