System Architecture

The architecture that will be used for a CDMA2000 deployment is effectively
the same as that used for an existing IS-95 system with the exception
of the Packet Data Serving Node (PDSN) network, which is introduced with
CDMA2000 systems. Additionally, it is important to note that 1xRTT in
CDMA2000-1x utilizes a spreading rate of 1 (SR1), which is directly compatible
with IS-95 because that system utilizes the same spreading rate.
However, CDMA2000-1xRTT now incorporates packet data sessions, and this change, as discussed previously, is implemented through the use of new
vocoders as well as channel element cards.
Because the majority of CDMA2000 systems have IS-95 deployed, the
choice or, rather, design is determined by the decision to use and how to
deploy DO or DV channels, their coverage areas, and of course the number
of carriers that will exhibit these new features.
A wireless operator can choose three basic scenarios, assuming two or fewer
IS-95 CDMA carriers are deployed in the network. Obviously, if more IS-95
carriers are deployed, the concept discussed next can easily be expanded upon,
but two carriers were chosen to ensure the clarity of the concept.
There are six general scenarios for deploying CDMA2000-1x into a wireless
system, whether it is an existing system that has IS-95 deployed or not,
and the are identified below:
■ CDMA2000-1x into existing IS-95 (F1 replacement)
■ CDMA2000-1x into existing IS-95 (F2/F3 or greater)
■ CDMA2000-1xEV-DO into existing IS-95 (F2/F3 or greater)
■ CDMA2000-1xEV-DV into existing IS-95 (F1 replacement and
possibly F2)
■ CDMA2000-1x and 1xEV-DO intonew system
■ CDMA2000-1xEV-DO and 1xEV-DV into new system
Some recommended channel deployment methods for cellular and PCS
systems are shown in Figures 5-13 through 5-16. Figure 5-13 is the recommended
channel deployment scheme for both a cellular A and B band operator.
The methodology used for deciding upon the channel deployment
enables legacy systems to still exist and remain in the AMPS band, besides
the EAMPS band. The reason for the AMPS band is to enable existing 1Gand
2G-capable phones to still have the capability to access the network for
ROAMing as well as emergency services like 911. The EAMPS portion of
the band can be used for analog, Cellular Digital Packet Data (CDPD), and
IS-136 services.

Figure 5-14 is similar to that shown for a CDMA2000-1x deployment
scheme with the exception that it involves the allocation of channels so that
a 3X system can be deployed in the network at a future date. The obvious
impact is on the channel bandwidth requirements due to the none contiguous
channel deployment scheme if a carrier designated for eventual 3X service
is initially implemented for 1x capacity relief.
Figure 5-14 also represents two different methods for deploying the
future 3X into a network. Figure 5-14a is an example of allowing for guard
bands between the 1X and 3X platforms, whereas Figure 5-14b follows the
current recommendation for channel allocations.
However, the recommended method for deployment is to deploy the 1x
systems in a contiguous fashion and then at a future date, when 3x is available,
migrate the channels to the new designations to support 3x.
Table 5-7 may be of some help in determining the assignment of a 1x
channel. However, the ultimate decision is based on the marketing plan, the
services offered, the current-capacity requirements, and the expected take
rates of both voice and data.
The next set of figures is meant to illustrate the recommended PCS
channel deployment schemes that can be implemented. Because the channel
assignment scheme is operator-dependant, that is, the channel set is
pre-programmed, the specific channel numbers associated with F1, F2, and
F3 are not defined as in cellular systems.

Figure 5-15 is an example of a PCS system that is allocated 5 MHz of
duplexed spectrum. The deployment scheme shown in Figure 5-15 is the
preferred method that happens to be the same whether 1X is the only
deployment contemplated or if a 3X deployment is planned for some date in
the future.
The next channel deployment scheme is shown in Figure 5-16 and represents
a methodology that bridges 2G, 2.5G, and of course 3G deployment
schemes. Without performing any traffic studies, it is recommended that
the initial deployment of CDMA2000-1X into any market involves a 1x
channel and not the DO, unless there is a infrastructure vendor restriction.
The rational behind this methodology of deployment lies in the uncertainty
of the take rate and data throughput requirements for wireless packets. By
implementing a 1x channel, the voice network is still served, while data is
available for delivery. Once the packet data’s take rate and usage patterns
are better understood, then the possibility of a more robust deployment of
DO channels can be envisioned.

Figure 5-17 shows an alternative method for implementing 3G services
into the PCS band. More specifically, the channel deployment scheme
enables the operation of both IMT2000-MC and DS systems side by side.
Obviously, the primary channels for CDMA2000-1x are in the middle of the
band and assume the obvious that no microwave clearance issues are left to
be addressed at this time in the system’s life cycle.