Wireless Facts; The Link Budget Tool - Redline AN-30 System User Manual

AN-30 System User Manual
10.3.

Wireless Facts

Wireless technology has existed for many years, proving itself to be a reliable
communication medium, primarily for long haul point-to-point applications supporting
critical links across the country for telephony and broadcast services. With the surge of
broadband two-way internet use, fixed wireless systems are playing an even more
important role in supporting network infrastructures.
The AN-30 system has been designed to operate in the band, which occupies the license
exempt portion of the spectrum. This allows an operator to set up a wireless network
without requiring formal consent from the regulatory agent. While this provides great
advantages in terms of cost and time to market, the ease of access to the spectrum can
bring with it undesirable effects, such as potential interference arising from other users
exploiting the "free" band. By following the simple deployment guidelines in this
manual, issues of this nature can be avoided.
This section provides additional background material to section 6 of this manual,
including a description of the Link Budget tool, Fresnel zone considerations, height
calculations, interference issues and radar horizon considerations.
10.3.1.

The Link Budget Tool

Redline has developed a Link Budget Tool to help characterize the range performance of
the AN-30 system for LOS, OLOS (optical line of sight) and NLOS conditions and
various system parameters. The Link Budget Tool can be obtained by contacting your
Redline certified partner or system integrator. Note the tool provides a first-order
approximation, and does not consider the details of any specific terrain profile which may
impact performance; rather, a generalized terrain is used in the calculations, based on
empirical formulas approved by governing bodies such as the IEEE and ITU. Also, the
tool does not consider system parameter variations arising from temperature fluctuations,
cable loss tolerance, antenna alignment errors, etc.
The Link Budget Tool estimates the distance over which the system can operate at a
desired error rate while achieving robust communication. A link is considered robust if
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the average error rate is less than 1 bit out of every 1000 million, expressed as 10 , for an
availability of 99.99%. Availability is described in more detail below.
The table below describes the net data rate (after coding overhead) that can be obtained
for each modulation type in an ideal propagation situation.
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