In many countries broadband wireless access is playing a growing role in enhancing accessibility to and adoption of broadband services. In developing economies with very limited or inadequate fixed local access networks broadband wireless access has already exceeded or will soon surpass the number of broadband subscriptions to fixed access networks, notably DSL. <\/p>\n
However, the capacity of wireless access in terms such as Mbps\/km2 is inherently more limited by the laws of physics (e.g. the Shannon limit on the spectral efficiency of the air interface) and the techno-economic realities which network engineering has to respect (e.g. the amount of available bandwidth) than is the capacity of wired access.<\/p>\n
Wireless networks, even with new “4G” technologies will likely not be able to keep up with projected broadband traffic volumes in urban and dense urban areas containing several thousands of inhabitants\/km2, as broadband penetration increases and new, more powerful applications come on line.<\/p>\n
Early signs of this risk are apparent in the congestion and other problems that have been reported as a result of the demands of iPhone users on AT&T’s 3G network in the U.S. Nor will wireless ever be able to match the total capacity that can be provided to serve an area by fiber-intensive local networks.<\/p>\n
Furthermore mobile operators who target fixed and nomadic broadband use which includes much in-building usage will find that the investments they have to make if they rely only on wireless access could be far larger than if they limit themselves to outdoor uses.<\/p>\n
The growing substitution of fixed voice by mobile voice services even in developed countries with widespread fixed access infrastructure may be fueling an overoptimistic expectation for the scale of the eventual role of wireless access in the very different era in which traffic is dominated not by voice services but by the use of broadband applications.<\/p>\n
Public policy authorities, as in the ”digital strategies” already announced by countries such as Finland and Australia, as well as operators need to recognize the essential role that new generation fixed access networks will have to play if their long term broadband ambitions are to be satisfied.<\/p>\n