Delivering a Consistent User Experience

The challenge will be how to deliver a consistent user experience. Hot spots, such as
airports and convention centers, are already saturated with cellular coverage, and the
cellular networks often already occupy much of the available soffit space and conduit
bandwidth, often using RF over fiber distributed antenna systems.
Wireless LANs will also need to compete with TDD Node B transceivers capable of
delivering a (probably sufficient) consistently good-quality 2 Mbps data stream. The
ISM band is unlimited, and anyone can use it, provided they do not exceed specified RF
power outputs. Machines co-sharing the spectrum could include industrial, scientific,
and medical microwave devices and Bluetooth devices (in the 2.4 GHz band). Note also
the band allocations at 5 GHz are different for the United States and Asia. Physical layer connectivity may therefore be rather inconsistent from location to location and certainly
inconsistent from country to country. There are also differences in terms of allowable
effective isotronic radiated power (EIRP) at 2.4 GHz—1 W for the United States, 100
mW for Europe, and 10 mW per MHz for Japan (26 MHz).
Even if the physical layer connectivity issues are addressed, there still remain substantial
application layer connectivity issues. Even if the application layer connectivity
issues are resolved, there still remain issues of physical access to hot spot locations
already intensively served by existing cellular vendors. And even if the physical access
issues are resolved, issues of billing and resolution of revenue capture disputes
between competing wireless LAN operators and established cellular vendors still
remain. 363