Migration Path

The migration path that a wireless operator must take to realize
CDMA2000 as envisioned for 3G is usually thought of as a staged approach
for implementation. The concept behind the phased approach is to enable
wireless operators using IS-95 platforms to migrate toward 3G without
having to either forklift their existing platforms or acquire a new spectrum.
CDMA2000 also is backward-compatible with existing 2G CDMA systems,
thereby speeding time to market.
From an operator’s point of view, the migration from 2G to 3G and the
realization of 3G must include
■ It needs to be cost effective based on the capital infrastructure already
in place
■ Increased capacity and throughput both in voice and data services that
utilize existing spectrum allocations
■ Standard systems that enable backward as well as forward
compatibility with other network and data platforms
■ The flexibility to meet the ever-changing market conditions

CDMA2000 phase1 is an interim step between IS-95B and full realization
of the IMT-2000 MC specification. CDMA200 can be deployed in an
existing IS-95 channel or system and will exhibit the numerous enhancements,
some of which are included here:
■ 1X and 3X 1.25-MHz channel support
■ 144-Kbps packet data rates
■ 2X increase in voice capacity
■ 2X increase in standby time
■ Improved handoff
It is envisioned that IS-95, CDMA200 1xRTT, and CDMA2000-3xRTT
can and will coexist in the same market and possibly at the same cell site.
Obviously, one can take numerous approaches in the course of implementing
any technology platform, and CDMA2000 is by no means unique to this
situation. However, several common migration paths are being pursued for
implementing CDMA2000. The migration path, of course, is dependent
upon whether the operator is currently utilizing IS-95A/B or J-STD-008
and upgrading to CDMA2000, or in the process of either installing a new
system or segmenting the existing spectrum to facilitate the introduction of
CDMA2000 into the network (see Table 4-5).

The following are three, 3, possible migration paths an operator may
persue.
CDMAOne (IS-95A)—CDMA2000 (phase1)—CDMA2000 (phase2)
CDMAOne (IS-95A)—CDMAOne (IS-95B)—CDMA2000 (phase1)—
CDMA2000 (phase2)
CDMA2000 (phase1)—CDMA2000 (phase2)
To complicate matters a little more for migration issues, several interim
steps within the CDMA2000 implementation process bear mentioning relative
to the single carrier (1x) aspects. The expected migration path or,
rather, the options for possible deployment of a CDMA2000-1x system are
shown in Figure 4-7.