
Unlike WiMAX, which was incubated inside IEEE 802.16 family and evolved from earlier 802.16 technologies, 802.20 [5] or Mobile-Fi was designed from ground up as a technology to support high-mobility services. It aims to support mobility as high as 250 km/h and a peak rate of up to 260 Mbps in the licensed spectrum below 3.5 GHz. Th e enabling technologies are also OFDM, MIMO, and beam-forming. The draft standard is still under the IEEE standardization process.
Both WiMAX and 802.20 use OFDM-MIMO, which is emerging as the main technology for future cellular packet data networks, including 3GPP long-term evolution and 3GPP2 air interface evolution as well.
Countries and companies often seek to control the market by developing standards they hope will dominate the global scene. The United States has led the way with IEEE standards, and the European Union's ETSI standards are their counterparts. The work of standards consensus is ongoing, uncertain, and difficult to predict. Mobile operators, who are generally friendly to Mobile WiMax, see Mobile-Fi as a competing standard that could make their 3G licenses worth rather less than they paid for them. The fact that Intel is behind WiMax is a strong force and will undoubtedly push the WiMax standards forward.
Mobile-Fi will have to overcome several hurdles. First among them is the fact that it can be used only in licensed bands below 3.5GHz. Another is that Mobile-Fi trails the Mobile WiMax standards process by a couple years. Another hurdle is whether there is indeed a large requirement for 155 mph (250 kph) handoff. In addition, we do not know what effect Mobile WiMax being nationalized in Korea will have. And, very importantly, cellular companies may not be willing to undercut their 3G service. Certainly, we can assume that the US$100 billion investment in 3G spectrum by the European mobile carriers alone might be weighed against a workable Mobile-Fi standard. With the possibility of proprietary systems (e.g., WiBro, Flash-OFDM) being in place a number of years before Mobile-Fi is standardized, the likelihood is that by then, Mobile WiMax will be backward compatible with WiMax fixed services. Licensed or unlicensed, Mobile-Fi will not be ubiquitous, and WiMax probably will.
* Official IEEE 802.20 website