Integration with Existing 1G Systems

The advent of 2G digital systems brought about several implementation
issues that the existing operators and infrastructure vendors needed to
solve. At heart of the issue was how to cost-effectively implement 2G into an
existing analog network. The problems involved the available spectrum,
existing infrastructure, and subscriber equipment. Most of the staff that
went through this period of time can remember the issues.

For the cellular operators, several options or rather decisions needed to
be made for how to integrate the new system into the existing analog network.
However, for PCS operators, the integration with legacy systems did
not present a problem since there was no legacy system. The PCS operators
in the United States had one other obstacle to overcome and that dealt with microwave clearance issues because the radio frequency spectrum auctioned
for use for the PCS operators was currently being used by 2-GHz
point-to-point microwave systems.

The integration with the existing 1G, legacy, systems was therefore an
issue that only affected the analog systems operating in the 800/900-MHz
bands. The 2G technologies that were applicable involved GSM,TDMA, and
CDMA radio access systems. Several options were available for the 1G
operators to follow, and they are listed in this section relative to each access
platform since the actual implementation also is technology-dependent.