User's Manual

UtiliNet® Endpoint User Guide 1-5-2007
Page 18 of 30
© Cellnet 2005
Traditional Radio Comparisons
Much of the work involved in the layout of a traditional voice or analog radio network deals with its
variability and uncertainties. Its design can be quite complex. This is simply the nature of analog
technology.
Digital radio, however, is different. System designers with a background in analog radio may find installing
a UtiliNet system to be somewhat simplistic. Network users, when field testing to determine how far radios
can communicate, describe it as either it does or it does not work. This is the nature of digital radio.
Network designers and users benefit from a UtiliNet radio’s intelligence in many seen and unseen ways.
The benefits of microprocessor-controlled communication algorithms are reduced installation time, reduced
cost, and reliability uncertainties. Because UtiliNet radios dynamically adapt to changing conditions,
designers can be confident that what will work today will work in the future.
UtiliNet also assures you that if the radios can communicate, then the data is correct. That is because,
unlike traditional pass-through radios that include no provisions for interference protection at the data level,
UtiliNet guarantees it through the benefits of packet switching.
Line-Of-Sight
Like traditional radios, UtiliNet radios operate in the 900 MHz range of the radio frequency spectrum and,
therefore, fall into a class of communications equipment referred to as line-of-sight. As a general rule of
thumb, line-of-sight communications equipment requires a clear, unobstructed view from the source radio
to the destination radio in order for communications between the two to occur.
Network Design for 900 MHz Systems
Network design for 900 MHz system typically falls into two categories:
• The first category includes licensed channels that are generally trunking or MAS data systems.
This category, in most cases, requires that all remote fixed points and/or mobile points have line-
of-sight paths to a single repeater site typically located at the highest point in the geographic area
of coverage.
• The second category includes spread spectrum systems into which UtiliNet falls. However, unlike
other spread spectrum radios, UtiliNet radios utilize an OSI network layer. Each radio has store
and forward features that allow intermediate nodes or routers to route data packets in cases where
line-of-sight between the source and destination is not possible. A patented geographic addressing
scheme is the method used to route the data through the network nodes.
In any case, the design of a 900 MHz communications network becomes a matter of providing line-of-sight
paths between radios.
In most systems, the end points of the network are typically well defined and established. The data delivery
points (master sites) as well as the data gathering points (remote sites) are known. In order to design a
UtiliNet network that allows communications between the delivery points and the gathering points, a
design plan similar to the following should be used:
1. Using a GPS receiver or geological maps, record the latitude and longitude of each data
delivery/gathering point in the network.
2. Determine an approximate available antenna height for each site. This only needs to be an
approximation. In some cases, the site may have height limitations due to clearance problems or