Wireless Migration

In the previous sections of this chapter, some of the various technology platforms
were discussed. The existing wireless operators today, regardless of
the frequency band or existing technology deployed have or are making
very fundamental decisions as to which direction in the 3G evolution they
will take. The decision on 3G technology will define a company’s position in
the marketplace for years to come.
Some existing operators and new entrants are letting the technology
platform be defined by the local regulator, thereby eliminating the platform
decision. However, the majority of the operators need to determine which
platform they must utilize. Since the platforms to pick from utilize different access technologies, they are by default not directly compatible. The utilization
of different access technologies for the realization of 3G also introduces
several interesting issues related to the migration from 2G to 3G.The
migration path from 2G to 3G is referred to as 2.5G and involves an interim
position for data services that are more advanced than 2G, but not as robust
as the 3G envisioned data services.
Some of the migration strategies for an existing operator involve
■ Overlay
■ Spectrum segmentation
The overlay approach typically involves implementing the 2.5 technology
over the existing 2G system and then implementing 3G as either an overlay
or in a separate part of the radio frequency spectrum they are allocated,
spectrum segmentation.
The choice of whether to use an overlay or spectrum segmentation is naturally
dependant upon the technology platform that is currently being
used, 2G, the spectrum available, the existing capacity constraints, and
marketing. Marketing is involved with the decision because of the impact to
the existing subscriber base and services that are envisioned to be offered.
Some of the decisions are rather straightforward involving upgrading
portions of the existing technology platforms that are currently deployed.
Other operators have to make a decision as to which technology to utilize
since they either are building a new system or have not migrated to a 2G
platform, using only 1G.
In later chapters various migration strategies are discussed relative to
the underlying technology platform that exists.