Deployment

The deployment of CDMA2000 into a new network is different than integrating
it into an existing network. To be more specific, the traffic volumes
and usage patterns are undefined in an initial system, leading to a homogenous
traffic distribution from the onset since the focus is more coverageoriented.
For the existing system, the focus is on the capacity release and
the introduction of new services, and the subscriber patterns are already
known. However, the patterns have not been developed for the new services,
therefore leading to much speculation as to where the usage will come from
and how the subscribers will utilize the new service.
Regardless of the situation, the deployment of the system requires a decision
as to where CDMA2000 will be introduced since, for all practical purposes,
the possibility of a complete 1:1 deployment of CDMA2000 will not
take place because of capital and implementation issues, which always
arise during any capital build program or expansion.
Figure 5-18 is an example of a hypothetical system that has IS-95 fully
deployed in the sample system with either one or two carriers per site. The
choice of omni cells has been done for illustrative purposes, and in order to
facilitate the discussion, in real life the sites would most likely be sectored,
making the diagram very cluttered.

The layout depicted in Figure 5-18 involves a total of three BSCs that are
all connected to the same MSC. Several class 1 roads are shown in the figure,
indicated by darkened lines that pass between the BTSs. BSC boundaries
are also shown and it is assumed for the discussion that they are
optimally located.
Figure 5-19 shows in a more visual method the BTSs that are associated
with the BSCs and the amount of carriers each has in operation. A review
of the diagram clearly indicates that the system has soft, softer, and hard
handoffs that can take place within the network with IS-95.
Therefore, Figure 5-20 is an example of how CDMA2000-1x could be
deployed into an existing IS-95 network. A quick comparison between Figures
5-19 and 5-20 illustrates several key issues. The first major item is
that no new carriers are added in the expansion, and the carriers are
upgraded from IS-95 to being CDMA2000-1x-capable. The second issue is the CDMA2000 is only added at sites that have a second CDMA carrier or
are adjacent to a site having a second CDMA carrier. The BSC boundaries
remain the same, but in reality they would be altered to minimize the
potential for BSC-BSC handoffs either for voice or packet data sessions.The
concept illustrated is that not all the sites within the system need to be
immediately upgraded to CDMA2000 from the start.
It does not take long to envision many different issues in the example
shown, leading to a strong need to coordinate the CDMA2000 deployment
within an existing system with the sales and marketing departments in
order to best manage the capital resources of the network.