Andrew Seybold: A Worldwide Swath of Spectrum?

The ITU and its World Radio Administrative Congress (WARC) is the body that has divided up spectrum for use in various parts of the world. Within each of the major geographies, the spectrum is sometimes used for different types of wireless.

For example, our 850-MHz cellular band is used in China, Latin America, Canada and other places, but not in Europe where they chose to use the 900-MHz portion of the spectrum for their first GSM networks. In places such as Israel, a portion of the 900-MHz band is used for the military. 

As a result, to build an almost world phone at least five different frequency bands (850, 900, 1800, 1900 and 2100 MHz) need to be included. (Japan's wireless spectrum is the same as ours but the transmit and receive bands are flipped, though this is changing.) In the United States, we have new AWS spectrum that will have to be added, and after the 700-MHz auctions we will have yet another band to contend with.

Now the United Nations has decided to try to replicate our 700-MHz spectrum around the world. The rationale for this is to provide several things. The first is a harmonized portion of spectrum that will be used in every nation over time. In the U.S., this spectrum will be available for use in 2009-2010 while in other parts of the world it will not be available until the 2012-2015 timeframe. Another reason is because radio waves at this frequency travel further and penetrate buildings and foliage better. Thus larger areas can be built out with fewer cell sites. 

According to Michael Thelander CEO and founder of Signals Research in Oakland, Calif., it would take approximately 10,000 cell sites to cover 75 percent of the U.S. population on 700 MHz (that is only 3 percent of the land mass), and on 2.5 GHz, where WiMAX is being deployed, it would take more than 62,000 cell sites to cover the same percentage of the population. The caveat here is that the 2.5 GHz system would have a lot more capacity because the sites would be closer together, but using 700 MHz is still much more economical.

This is the key reason that the UN is considering trying to harmonize this spectrum around the world. The idea is that it is the best-suited spectrum available for broadband services to cover underserved markets that cannot, today, be served economically using the higher frequency bands. 

Since each site covers more area, fewer sites need to be built in rural or undeveloped areas around the world. If data demand dictates, additional cell sites can be installed to increase capacity, but this would happen only where there is a high demand for data and the system was paying for itself.

I envision these systems making use of next-generation technologies-UMB (Ultra Mobile Broadband) from the CDMA side, LTE (Long Term Evolution) from the GSM/UMTS community or perhaps even a new version of WiMAX. These new technologies more than triple current data speeds and add more capacity per cell. They are also IP-based from the airlink through the entire system making them easier to deploy and lowering the cost of the back-end systems.

Having a single band for worldwide data services (and for VoIP in the future) would mean that the cost of both the cell sites and the wireless user devices would come down due to the sheer volumes. This, too, would make the economics of deploying wireless broadband more attractive and thus more rural areas around the world could receive the benefit of wireless services. The cost of deploying wired technologies to rural areas makes it an unrealistic option.

I hope the UN is successful and we do end up with one single band around the world. The biggest fight will be over which technology will be deployed over this spectrum. In Europe and other parts of the world, governments dictate which technology can be deployed in which frequency band and this is why they have only GSM/UMTS and their mobile TV will most likely be DVB-H. In the United States and many other nations, the spectrum is unencumbered by the technology choice.

In reality, it won't make much of a difference even if UMB, LTE and WiMAX are all built out on this band. The chipsets or software-defined radios to support all of these technologies will be almost as inexpensive as a single-technology solution.

This common band is a great idea and very logical, so my prediction is that it won't happen. Instead, the UN will run into politics and other hindrances that will result in a failed effort-once again proving that wireless is not about technology at all, it is about who controls the spectrum.

Andrew Seybold is an authority on technology and trends shaping the world of wireless mobility. A respected analyst, consultant, commentator, author and active participant in industry trade organizations, his views have influenced strategies and shaped initiatives for telecom, mobile computing and wireless industry leaders worldwide.

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