Subject: [NEXTEL-1] Unlicensed Radio Communications in a Changing Regulatory Environment

From: [email-masked]
Date: Mon, 08 Dec 2003 09:24:36 -0500

Unlicensed Radio Communications in a Changing Regulatory Environment

A White Paper on Supervisory Control
and Data Acquisition systems (SCADA)
 communications

Overview
The wireless revolution is having a major impact on how we set up and
communicate between nodes in a supervisory control and data acquisition
system (SCADA). MDS is a world leader in wireless data networking solutions
with applications in the SCADA, telemetry, telecommunications, and on-line
transaction processing markets.

In the past, customers needing wireless communication systems would be
required to obtain an FCC license. In some localities, licenses are becoming
difficult, or even impossible, to obtain.

A popular solution to the licensing problem is provided by the emergence of
Spread Spectrum (SS) technology. This new digital technology provides most
of the capabilities and performance of a licensed radio system with a
license-free approach. For long distance data communications in a control or
data gathering application, Frequency Hopping Spread Spectrum (FHSS) radios
provide a robust solution. Spread Spectrum typically uses the frequency band
of 902 to 928 MHz. Today's new digital radios employ frequency hopping
within this range to ensure maximum performance and maximum reliability for
SCADA communications. Sophisticated hopping sequences and forward error
correction reduces interference from unwanted sources. These radio
enhancements provide very low bit-error rates and greater range of use.

In addition, use of Digital Signal Processing (DSP) technology allows
systems to communicate at speeds of 19.2 kbps, and higher, even with weak
signals and in the presence of interference. The added intelligence created
by the use of microprocessors in the radio allows for improved diagnostic
facilities. These facilities allow for the monitoring and control of radio
parameters, locally at the radio, as well as via the master base station.

This paper briefly discusses the historical background of spread spectrum
radio, FCC rules and regulations, and the definition and application of
direct sequence and frequency hopping techniques. Also covered are system
architecture options, design, and installation considerations.

http://www.microwavedata.com/products/whitepapers/regulations.asp

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