Design Methodology

The methodology for the network and radio frequency (RF) design for
CDMA2000 needs to be established at the beginning of the process. The
establishment of the methodology utilized for the formulation of the report
is essential in the beginning stages to ensure the proper baseline assumptions
are used to facilitate flexibility in the design and implementation.
Flexibility is needed in the design and implementation to address many of
the future issues that are really unknown and therefore cannot be properly
foreseen at the onset of the design process itself.
Some of the issues that need to be identified at the beginning of study are
■ Time frames for the growth plan
■ Subscriber growth projections
■ Services offered with take rates
■ Design criteria
■ Baseline system numbers for building on the growth study
■ Construction expectations
■ Legacy and future technology systems
The time frame for the growth plan is essential to determine at the
beginning. The time frames will define what the baseline, foundation, and
how much of a future look the plan will present. Therefore the baseline
month or time frame associated with an existing system that the data used
for generating the plan is critical because the wrong baseline dates will
alter the outcome of the report.
The amount of time the plan projection is to take into account is also critical
for the analysis. The decision to project one year, two years, five years,
or even ten years has a dramatic effect on the final outcome and accuracy
of the forecast. In addition to the projection time frame, it is important to
establish the granularity of the reporting period—monthly, quarterly, biannually,
yearly—or some perturbation of them all.
The particular marketing plans also need to be factored into the report
itself. The marketing department’s plans are the leading element in any network
and RF growth study.The basic input parameters to the network and RF
growth plan provided by the marketing department is listed in the following:
■ Projected subscriber growth for the system over the time frame
■ Projected mErlangs per subscriber expected at discrete time intervals ■ Projected Mbps per subscriber expected at discrete time intervals
■ Dilution rates for the subscriber voice usage over the time frame
■ Dilution rates for legacy subscriber equipment over the time period
■ Types of subscriber equipment used in the network and percent
distribution of CPE projections
■ Special promotion plans over the time frame of the report, such as free
Internet access
■ The projected amount of mobile data users over the time frame of the
study
There are a multitude of other items needed from the marketing department
for determining network and RF growth. However, if you obtain the
information on the basic eight topics listed previously from the marketing
department, it will be enough to adequately start the RF, fixed network,
voice, and packet design.
The design, whether it is for new or expansion systems, needs to factor in
the following key elements along with the expected traffic loading forecast:
■ Spectrum available for use
■ Spectrum required and methods for achieving the required bandwidth
■ Flexibility to meet the ever changing market conditions
■ Cost effective use of the existing and future capital infrastructure
■ Standardized systems that enable backward as well as forward
compatibility with other networks and data platforms
■ QOS/GOS for each type of service offering
■ Coverage requirements either new or enhancements to existing
coverage
With the previous said, the next step is to establish some guidelines that
are specific to CDMA2000 systems.