User's Manual

5 Radio Network Planning
60 APCD-LM043-4.0
In all cases, these wide-ranging factors drive the system design and as a result, no two
systems will be implemented the same way.
The design methodology presented in this chapter uses a building-block approach. If the
system you are designing is based on a single CCU, you need only read and learn about the
guidelines presented in Basic System Design on page 60. If you need multiple CCUs or CAPs
to satisfy your network requirements, you must perform a much more detailed engineering
design based on the general guidelines provided in Multi-CAP RF Network Design
Considerations on page 67.
For purposes of illustration, coverage areas are presented using the popular cellular
hexagonal coverage pattern. In practice, radio coverage does not conform to hexagonal
shapes; however, hexagons are used to represent radio coverage because graphically, they
can fully cover a plane surface and because they provide an easy-to-understand
representation of coverage cells.
5.2 Basic System Design
Basic system design guidelines apply to all LMS4000 system implementations, from a simple,
single-CCU system, to more complex multi-CCU CAPs and multi-CAP networks.
5.2.1 Overview of Basic System Design
The basic design of the LMS4000 900MHz radio network involves the following procedures:
• Conducting a spectral survey to identify, quantify, and assess the impact of existing
in-band and out-of-band interference.
• Determining single- or multi-CAP system requirements based on RF coverage, CAP
locations, and system loading.
5.2.2 Spectral Survey of the Target Service Area
Before starting the system design, WaveRider recommends conducting a spectral survey of
the target serving area to determine the radio landscape—that is, to determine if there are any
in-band or out-of-band interferers and how, and to what degree, these interferers constrain
your system design (site location, frequency, equipment).
The spectral survey involves travelling to key locations throughout the target serving area,
especially to locations that may be potential CAP sites, or where there are significant numbers
of potential end users, and recording the radio spectrum (ISM band +/- 10MHz) at each of
these locations. The survey requires the use of a spectrum analyzer and a trained RF
engineer who is capable of interpreting the results. There are a number of independent RF
engineering firms that can provide this service, including the WaveRider Professional Services
Group. If you have access to the required equipment and in-house skill set, you can also
conduct this survey yourself.
The spectral survey is a critical first step in the system design. Not only does it provide the
starting point for the RF network design, it establishes a baseline for the use and occupancy of