Landis Gyr Technology EC3R1S4 GE kV2c UTILINET ENDPOINT User Manual USERS MANUAL
Landis+Gyr Technology, Inc. GE kV2c UTILINET ENDPOINT USERS MANUAL
USERS MANUAL
5015 B.U. Bowman Drive Buford, GA 30518 USA Voice: 770-831-8048 Fax: 770-831-8598
FCC Part 15.247 Certification
Test Report
FCC ID: R7PEC3R1S4
FCC Rule Part: 15.247
ACS Report Number: 06-0386-15C
Manufacturer: Cellnet Technology, Inc.
Model: GE kV2c Utilinet Endpoint
Manual
UtiliNet® Endpoint User Guide 1-5-2007
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© Cellnet 2005
UtiliNet® Endpoint User Guide
UtiliNet® Endpoint User Guide 1-5-2007
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© Cellnet 2005
Version: 1.1
Revision History
Rev # Date Author Pages Description
1.0 1/16/2005 H. Glass
R. Ridenour Initial
Document
Creation
1.1 11/1/2006 M. Ruff Update Module
List/Tech
Specs
1.2 1/5/2007 M. Ruff 13 Add antenna
config details
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© Cellnet 2005
Proprietary Rights Notice
This manual is an unpublished work and contains the trade secrets and confidential information of Cellnet,
which are not to be divulged to third parties and may not be reproduced or transmitted in whole or part, in
any form or by any means, electronic or mechanical for any purpose, without the express written
permission of Cellnet. All rights to designs or inventions disclosed herein, including the right to
manufacture, are reserved to Cellnet.
The information contained in this document is subject to change without notice. Cellnet reserves the right
to change the product specifications at any time without incurring any obligations.
Trademarks Used in This Manual
Internet Explorer® is a trademark of Microsoft Corporation.
UtiliNet® is a trademark of Cellnet Innovations, Inc.
Cellnet® is a registered trademark of Cellnet Innovations, Inc.
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Revision History _____________________________________________________2
FCC/IC User Information_______________________________________________6
Chapter 1 Introduction _____________________________________________7
System Overview........................................................................................................... 7
UtiliNet Basics ............................................................................................................... 7
Network of Intelligent Radios..................................................................................... 8
Mesh Architecture....................................................................................................... 8
Radios With Programmable Intelligence.................................................................... 9
Packets Hop From Radio To Radio ............................................................................ 9
Polling and Report By Exception ............................................................................... 9
About This Manual....................................................................................................... 9
Icons............................................................................................................................ 9
Contacting Technical Support __________________________________________10
Chapter 2 UtiliNet Endpoint Under-Glass Radio__________________________10
System Overview......................................................................................................... 10
UtiliNet Module Overview ......................................................................................... 11
Technical Features of the UtiliNet Endpoint Under-Glass Radio.......................... 11
Residential Meter Modules ____________________________________________11
Chapter 3 UtiliNet Endpoint Configuration _____________________________13
Connecting to a radio.................................................................................................. 13
Adding new Radios to RadioShop............................................................................. 14
Communicating with integrated meter modules...................................................... 15
Setting the Latitude and Longitude .......................................................................... 15
Updating the Network ID (CRC Adder)................................................................... 16
Chapter 3 Network Engineering______________________________________17
Network Design Plan .................................................................................................. 17
OSI Layers ................................................................................................................ 17
Traditional Radio Comparisons................................................................................ 18
Line-Of-Sight............................................................................................................ 18
Network Design for 900 MHz Systems...................................................................... 18
Calculating Latitude/Longitude Coordinates............................................................ 19
Global Positioning System (GPS)............................................................................. 19
United States Geological Survey Maps - USGS Maps............................................. 20
MapInfo..................................................................................................................... 20
RF Considerations and System Design..................................................................... 21
Radio Link Budget.................................................................................................... 21
Transmitter................................................................................................................ 21
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Transmit Antenna...................................................................................................... 21
Ground Plane Effects................................................................................................ 21
Transmitter Transmission Line Loss ........................................................................ 22
Total Path Loss ......................................................................................................... 22
Free Space Path Loss ................................................................................................ 22
Additional Path Loss Attenuation............................................................................. 22
Receiver Antenna...................................................................................................... 23
Receiver Transmission Line Loss............................................................................. 23
Receiver .................................................................................................................... 23
Noise Floor Factor .................................................................................................... 23
Multipath Fade Factor............................................................................................... 23
Margin of Safety ....................................................................................................... 24
Summary................................................................................................................... 24
Keeping a Check on Interference.............................................................................. 25
In-Band Interference................................................................................................. 26
Out-of-Band Interference.......................................................................................... 26
Cellular Base Station Interference ............................................................................ 26
Paging System Interference ...................................................................................... 26
Performing RF Field Studies .................................................................................... 26
Design Considerations .............................................................................................. 27
Glossary___________________________________________________________28
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FCC/IC User Information
FCC Class B
ThisdevicecomplieswithPart15oftheFCCrules.Operationissubjecttothefollowingtwo
conditions:
(1)Thisdevicemaynotcauseharmfulinterference,and
(2)Thisdevicemustacceptanyinterferencereceived,includinginterferencethatmay
causeundesiredoperation.
ThisequipmenthasbeentestedandfoundtocomplywiththelimitsforaClassBdigitaldevice,
pursuanttoPart15oftheFCCRules.Theselimitsaredesignedtoprovidereasonableprotection
againstharmfulinterferenceinaresidentialinstallation.Thisequipmentgenerates,uses,andcan
radiateradiofrequencyenergyand,ifnotinstalledandusedinaccordancewiththeInstructions,
maycauseharmfulinterferencetoradiocommunications.However,thereisnoguaranteethat
interferencewillnotoccurinaparticularinstallation.Ifthisequipmentdoescauseharmful
interferencetoradioortelevisionreception,whichcanbedeterminedbyturningtheequipment
offandon,theuserisencouragedtotrytocorrecttheinterferencebyoneormoreofthe
followingmeasures:
• Reorientorrelocatethereceivingantenna.
• Increasetheseparationbetweentheequipmentandreceiver.
• ConsultCellnetoranexperiencedradiotechnicianforhelp.
Changes or modifications to this device not expressly approved by Cellnet
Technology, Inc. could void the user's authority to operate the equipment.
RF Exposure
InaccordancewithFCCrequirementsofhumanexposuretoradiofrequencyfields,
theradiatingelementshallbeinstalledsuchthataminimumseparationdistanceof20
centimeterswillbemaintained.
Industry Canada
ThisClassBdigitalapparatuscomplieswithCanadianICES‐003.Cetappareilnumériquedela
classeBestconformeàlanormeNMB‐003duCanada.
ThisClassBdigitalapparatusmeetsallrequirementsoftheCanadianInterferenceCausing
EquipmentRegulations.Operationissubjecttothefollowingtwoconditions:
(1)thisdevicemaynotcauseharmfulinterference,and
(2)thisdevicemustacceptanyinterferencereceived,includinginterferencethatmay
causeundesiredoperation.
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CetappareillagenumériquedelaclasseBrépondàtouteslesexigencesdelʹinterférence
canadiennecausantdesrèglementsdʹéquipement.Lʹopérationestsujetteauxdeuxconditions
suivantes:(1)cedispositifpeutnepascauserlʹinterférencenocive,et(2)cedispositifdoit
accepternʹimportequelleinterférencereçue,ycomprislʹinterférencequipeutcauserlʹopération
peudésirée.
Chapter 1 Introduction
This manual provides technical information for the line of radios used in the UtiliNet® Wireless System.
Included are photos, specifications, diagrams, and accessories for each radio type as well as detailed
information on applications using the radios and other related information.
System Overview
UtiliNet is a comprehensive wireless data communications solution that utilizes spread-spectrum radios in
the 902-928 MHz area of the radio spectrum to provide reliable network answers for remote telemetry or
distributed control applications. UtiliNet radios combine three important technologies: a mesh architecture
for peer-to-peer communications and true networking functionality, asynchronous spread spectrum
frequency hopping for maximum use of bandwidth, and packet switching for guaranteed message transfer
and automatic store-and-forward routing.
Figure 1.1 UtiliNet Technologies
These three technologies work together to ensure that UtiliNet networks are fast (up to 19200 bps), operate
transparently, and are reliable in the delivery of all data messages. These are the key advantages of
UtiliNet.
UtiliNet Basics
UtiliNet is a wireless data communications network based on spread-spectrum radio technologies.
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Network of Intelligent Radios
UtiliNet radios form the foundation of a UtiliNet network and serve multiple functions.
• Each radio can communicate to end devices for some data collection or control function.
This may involve transparent applications where data is merely passed through UtiliNet
radios, or it may involve programs running in radios and/or other gateway devices to perform
custom applications, higher network efficiency or enhanced functionality.
• Each radio interacts with its UtiliNet radio RF neighbors to form a wide area network (WAN)
into which it may initiate a packet, automatically route a packet between other radios, or
accept a packet as the final destination.
• Each radio automatically integrates itself into an RF wide area network and routes packets.
Upon power up or reboot, and at intervals while powered on, a radio automatically scans the
frequency band searching for other UtiliNet radios in its vicinity to learn about its RF
neighbors. As the radios learn about one another, they pass their geographic address
coordinates for routing and to keep communication statistics for choosing the best data
transmission paths. This allows the radios to automatically route packets and dynamically
build routing tables to choose the best paths if RF conditions change. Once configured by the
user, radios automatically acquire radios and route packets.
• Each radio can execute one or more programs written in the Device Control Word (DCW)
language.
These programs can send, receive, and process packets to and from other radios. They also are
able to send, receive, and process data to and from end devices connected to the radio.
Examples of DCW applications include: radio configuration, radio queries, data collection,
communication to end devices, protocol translation and peer-to-peer control.
Several types of UtiliNet radios are available:
• The UtiliNet Endpoint under-glass radio used for under glass meter integration and other
devices
• The Integrated WanGate Radio (IWR) and WanGate radio are used with RS-232 end devices
and as additional repeaters if necessary (the IWR is designed for installation inside another
enclosure and the WanGate is designed for independent outdoor installations).
• The MicroRTU WanGate radio allows an integrator to install an appropriate RTU into the
specialized MicroRTU WanGate enclosure to create a combined RTU and radio
communication package.
Mesh Architecture
Much like a giant net over a service area—UtiliNet radios work together to create a mesh. At each point
where one thread of the net crosses over another, a node is created in the wider area network.
A node could be represented by one radio attached to end-devices.
Because each radio can forward messages to and respond to every other radio in the network, each radio is
an equal participant in the network. The result is increased communication reliability because there is no
single point of failure. While a radio is interacting with an end-device, it can be simultaneously acting as
part of the mesh network. The concept of creating a mesh is central to what makes UtiliNet a truly robust
data communication solution.
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Radios With Programmable Intelligence
Each radio is similar to a programmable logic controller (PLC). The radio acts much like a small computer,
carrying out any number of computing and command functions. The intelligence in each radio enables it to
perform many functions not normally associated with radios such as making intelligent routing decisions,
transporting industry protocols, and recognizing operating conditions and responding with pre-programmed
logic.
Packets Hop From Radio To Radio
When an end device generates a message that needs to traverse the network, the end-device radio packets
the data, places the data into an envelope—addressed to the destination radio—and enters it into the
network. The data packet traverses the network by hopping from radio to radio in the direction of the
destination radio. The number of hops between origin and destination radio(s) is automatically minimized
to increase transmission speed. The route chosen for traversing the network is dynamic and employs
automatic re-routing in the event a particular data path is not clear.
Polling and Report By Exception
Traditional point-to-multipoint systems are prone to network latency as only one radio can communicate
with the master at a time. A mesh network eliminates this problem as data is evenly spread across the entire
mesh (i.e., a multipoint-tomultipoint network). Further, most traditional network topologies poll, gathering
data sequentially. UtiliNet radios can be programmed to respond under predetermined parameters or on an
unsolicited, report-by-exception basis—which is both faster and more efficient.
About This Manual
This technical reference guide explains UtiliNet in great detail from application design through
implementation and operation to after-sales services and support. Also included are a glossary of important
terms and papers on extended UtiliNet topics.
Chapter Title Description
1 Introduction Provides introductory information about the Utilinet
network and this manual.
2 UtiliNet Endpoint Under-
Glass Radio Describes the details of the UtiliNet endpoint module
3 UtiliNet Endpoint
Configuration Provides information for radio configuration, radio
installation, network routing, mobile radio configuration.
4 Network Engineering Contains information on network design, latitude/
longitude calculations, system design, and field studies.
Glossary Provides a list of terms and definitions commonly
used in UtiliNet radio applications.
Icons
Throughout the document, various icons are used to draw your attention to important information. Below
are examples:
The warning icon identifies information that is critical to maintaining
the integrity of the software or data.
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The caution icon identifies important information.
The note icon identifies information that clarifies a point within the
text.
Contacting Technical Support
Within the United States, Cellnet technical support is available Monday through Friday, 8:00 A.M. to 5:00
P.M. Eastern Standard Time by email at techsupport@cellnet.com . Please be prepared to give the
following information:
• Exactly what problem you encountered.
• A description of what happened and what you were doing when the problem occurred.
• A description of how you tried to solve the problem.
Chapter 2 UtiliNet Endpoint Under-Glass Radio
The UtiliNet Endpoint Under-Glass Radio is Cellnet’s latest embedded communication module product
targeting advanced RF communications for residential metering needs. The UtiliNet Endpoint is designed
to be integrated under the glass of an existing meter enclosure. It provides the following benefits:
• Low operational cost AMR solution
• Supports small to large deployments
• Eliminates recurring data collection fees
System Overview
The UtiliNet Endpoint system looks as follows:
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Data acquisition can be provided by a hosted service for small to large meter deployments or an own and
operate solution. The UtiliNet network provides secure, packet based data transfer. UtiliNet Endpoint
module supports the following system services:
• Uses Device Control Word (DCW) programming language
• Spread Spectrum Frequency Hopping Technology
• Utilizes an Unlicensed 902-928 MHz Frequency Band
• Devices act as end devices and repeaters
• Utilizes packet switching data transmission
• Increase coverage by adding more radios to the Mesh Network
UtiliNet Module Overview
The UtiliNet Endpoints are designed to for integration in both residential and commercial electric meters.
The following list includes all UtiliNet modules, and the associated host electric meter:
UtiliNet Module PCBA# Meter Model Meter Type
L&G Focus-2 Utilinet Endpoint 25-1053 Focus Residential
GE I-210 Utilinet Endpoint 25-1055 GE I-210 Residential
GE kV2c Utilinet Endpoint 25-1054 GE KV2c Commercial
Elster A3 Utilinet Endpoint 25-1014 Elster A3 Commercial
Technical Features of the UtiliNet Endpoint Under-Glass Radio
Endpoint Meter Modules
General Specification
Number of Channels 258
Channel Spacing 100 KHz
Modulation Type Direct 2-FSK
Baud Rate 9600
FCC Operation Part 15.247 Spread Spectrum
Spreading Technique Frequency Hopping
Hopping Technique Pseudo Random Asynchronous
Hopping Patterns 65,536 (Unique per network)
Network Address Latitude / Longitude Coordinates
Turn-Around Time 100[uS] max
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Transmitter Frequency
[MHz] Condition Specification
RF Output - Residential Minimum
Typical
902.1~927.9 Referenced to
Antenna
connector, CW
+14.0 dBm
+16.0 dBm
RF Output - Commercial Minimum
Typical
902.1~927.9 Referenced to
Antenna
connector, CW
+18.0 dBm
+20.0 dBm
Frequency Range f0 902.1~927.9 MHz
Out-of-band Radiated Spurious 10~10000
2*f0
3*f0~10*f0
1KHz RBW, TX
on, CW, +20
dBm
-20 dBc
-45 dBc
-70 dBc
Deviation +/-5.0 KHz
Modulation Bandwidth 25 KHz
Frequency Stability -40C ~ +85C f0 +/- 2.5ppm
Processing Specification
CPU Renesas M16C/62
Clock Speed 14.7456[MHz]
Memory
SRAM
Flash (Code + Data)
31[KBytes] internal
384[KBytes] internal
Programming Language Device Control Word (DCW)
Environmental Specification
Operating Temperature -40 to +85C
Storage Temperature -40 to +85C
Humidity ANSI 12.1 ~ 5.4.3.18
Receiver Frequency
[MHz] Condition Specification
Type Monolithic, Low IF,
Quadrature digitized
Receiver Sensitivity - Residential 902.1~927.9 BER 5E-5 -104 dBm typ/-102 dBm
min
Receiver Sensitivity - Commercial 902.1~927.9 BER 5E-5 -108 dBm typ/-105 dBm
min
Adjacent Channel Rejection > 50 dB
Worst case Image Rejection > 35 dB
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Endpoint Antenna Configurations
L&G Focus-2 Utilinet Endpoint Antenna:
This device has been designed with an integrated loop antenna, located on the PCB surface layer
on the reverse (non-component) side of the assembly. This antenna has a typical gain of 3 dB.
GE I-210 Utilinet Endpoint Antenna:
This device has been designed with an integrated loop antenna, located on the PCB surface layer
on the reverse (non-component) side of the assembly. This antenna has a typical gain of 3 dB.
GE kV2c Utilinet Endpoint Antenna:
This device has been designed to operate with the antenna listed below, and having a maximum
gain of 1 dB. Antennas not included in this list or having a gain greater than 1 dB are strictly
prohibited for use with this device. The required antenna impedance is 50 ohms.
GE kV2c Antenna – Flex Dipole, Cellnet p/n: 19-0077 or 19-1173
To reduce potential radio interference to other users, the antenna type and its gain should be so
chosen that the equivalent isotropically radiated power (EIRP) is not more than that required for
successful communication.
Elster A3 Utilinet Endpoint Antenna:
This device has been designed to operate with the antenna listed below, and having a maximum
gain of 3 dB. Antennas not included in this list or having a gain greater than 3 dB are strictly
prohibited for use with this device. The required antenna impedance is 50 ohms.
Elster A3 Antenna – Loaded Monopole, Elster p/n: 1B12150H01
To reduce potential radio interference to other users, the antenna type and its gain should be so
chosen that the equivalent isotropically radiated power (EIRP) is not more than that required for
successful communication.
Chapter 3 UtiliNet Endpoint Configuration
A local UtiliNet radio is required to communicate with the integrated UtiliNet radio modules inside your
meters. This radio may be a standard UtiliNet Series 3000 IWR radio as seen below.
Connecting to a radio
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Open RadioShop on your computer.
Connect your local radio’s Lan Packet Protocol serial port to your computers serial port. Select
Communications>>Connect from the RadioShop main menu making sure you select the right
Com port and a Baud rate. The default baud rate for UtiliNet radios is 9600 bps. When you are
connected to the local radio, a Radio Configuration Report will be executed automatically and
displayed.
UtiliNet radios, including integrated meter modules, ship with a default network configuration that
must be updated to reflect your company’s unique network ID.
In order to communicate with a UtiliNet meter endpoint over-the-air, the locally connected radio
must be a member of the same network as the integrated meter radio module.
Adding new Radios to RadioShop
You will now need to add the meter radios to the RadioShop database. This is be done by
invoking the automatic discovery feature from the Radioshop main menu. Make sure your local
radio is highlighted in the network view and select Utilities>>Radio>>Discover Neighbors from
the RadioShop main menu. This will automatically populate RadioShop’s database with all
required information about the integrated meter module in order to establish over-the-air
communication. All visible UtiliNet radio modules will be automatically added to the network
view in RadioShop.
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Communicating with integrated meter modules
In order to address a remote endpoint that has not been configured with a Latitude/Longitude you
must select the endpoint “via” your local radio. This tells the network what path to take to reach
the endpoint, which does not yet have a valid Latitude/Longitude. To select your endpoint “via”
your local radio, right click on the endpoint and select “Select Via…” from the context menu.
Once selected via, the text displayed in the network view should indicate that the remote endpoint
is selected via your local radio.
Setting the Latitude and Longitude
In order to give your device a fixed Latitude and Longitude you must first specify the meter
module as a “non-mobile” device. Do this by selecting Configure>>Send DCW from the main
menu and selecting the UMOBILE.HEX DCW. Once sent confirmation should be displayed on a
“DCW Response” tab as shown below.
Next you will have to set up a Latitude and Longitude or "”WAN Address” for your integrated
meter module. This is the GPS coordinates of the radio. To set the WAN address, go to
Configure>>Wan Address. Specify the new Latitude/Longitude of your integrated meter module
and click OK. A message should appear indicating that the remote radio was successfully
programmed. The color feature may be used if you are planning on installing more than one meter
in the same geographic location.
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Updating the Network ID (CRC Adder)
In order to configure your integrated meter module with your company’s unique network ID or
CRC Adder you must first add a network to RadioShop with your company’s network ID. Select
Utilities>>Network>>Add Network from the RadioShop main menu to access the “Add Network”
screen. Name the network and specify the network ID (CRC Adder) to your company’s assigned
value. You may accept the default parameters for the protocol settings or change these to match
your networks protocol settings if known.
Now you will be able to configure the radio to be a member of your new network. Select
Configure>>Radio from the RadioShop main menu. Select the default radio configuration file and
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the new network you would like the radio to be a member of and click OK. The radio will be
automatically moved to the destination network and updated with the destination network’s
network ID.
Note UtiliNet radios may only communicate on one network at a time. You will not be
able to communicate to the integrated meter radio over-the-air until you move your
locally connected radio to the same network.
For more information on UtiliNet module configuration, transparent port configuration, and
routing configuration see the UtiliNet Technical Reference Guide.
Chapter 3 Network Engineering
This chapter discusses the network design plan, calculation of latitude/longitude, RF considerations, field
studies and use of directional or gain antennas.
Network Design Plan
A UtiliNet network consists of two or more UtiliNet packet radios that communicate data to and from
points in the network. When designing a UtiliNet network, it is important to remember that UtiliNet
combines three different technologies: a connectionless (store and forward) mesh architecture, packet
switched data transfer, and spread spectrum radio techniques. Since this combination of technologies
affects the design layout and plays a part in the overall optimization of the network, each one is discussed
in this chapter.
OSI Layers
For those familiar with the Open Systems Interconnection (OSI) model, the above technologies, or OSI
layers, also address why a UtiliNet network communicates like a computer network. In fact, it is often said
that UtiliNet radios are computers that use radio waves to communicate with each other, or that end devices
do not talk through UtiliNet radios but to them. From a certain point of view, this is true. UtiliNet radios
are computers first and spread spectrum radios second. Truly optimizing the benefits of a UtiliNet network
requires understanding the interaction and purpose of the physical, data-link, network, transport, and
session layers of the OSI model.
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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
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aesthetics. In the 900 MHz frequency band, antenna height provides the largest gain in terms of
RF distance. In general, the higher that antennas may be mounted the better.
3. Use topographical maps or computer prediction programs to plot paths between known nodes to
get an indication of the ability of radios to communicate with one another over the average terrain
in the area. This procedure provides an approximation for required antenna height in order to clear
obstructions that may exist in the paths.
4. If path profiles are generated that indicate that certain sites DO NOT have line-of-sight paths to
any other site, use general area maps to identify where repeater or additional router locations
might be needed to insure line-of-sight paths from every radio to at least one other radio.
5. Field Survey - Regardless of the quality of maps or computer databases, predictions are still just
predictions. The only way to insure RF connectivity, regardless of the product or the frequency, is
to test the path.
Calculating Latitude/Longitude Coordinates
Each radio in the UtiliNet network is programmed with a unique latitudinal and longitudinal (lat/long)
coordinate. These lat/long coordinates are used by the network to make logical routing decisions (see
"Network Routing" on page 9-2 for more information). Because the network uses the lat/long information
in a logical way, it is not necessarily important that the lat/long coordinates be physically accurate. What is
important, is that the lat/long coordinates of each radio be relatively correct to one another.
In other words, if each radio in a particular network was programmed with the same distance offset from
the actual physical location, network routing would not be adversely affected. However, if only a few of the
radios were programmed with the offset, routing could potentially suffer due to logical routing that does not
reflect the physical topology of the network. Therefore, it is not necessary for radios to have exact
coordinates. What is important, however, is that the method used to derive the lat/long coordinates be
capable of providing repeatable coordinate information which is physically relative and consistent system
wide.
Below are the most common, commercially available, methods of deriving latitude longitude information.
A brief analysis has been provided to compare and contrast the benefits of each.
• Global Positioning Systems
• United States Geological Survey Maps
• MapInfo®
Global Positioning System (GPS)
GPS devices receive global positioning information from government owned and operated satellites. Many
manufacturers have developed consumer grade GPS devices for the commercial market. In most
commercial applications, the GPS is used to approximate a location while in motion (such as boating,
hiking, or skiing). These devices are readily available to the consumers for a price of about $500.00 or
less.
As a note, the signal from the government satellites has intentionally
been degraded for security purposes. Commercial grade GPS
specifications are typically +/- 300 meters. Only industrial grade GPS
equipment, with a land based reference, will provide the type of
accuracy used in military applications.
When considering the use of a GPS for constructing and maintaining a UtiliNet network, here are some
issues to evaluate:
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Repeatability of the GPS information has proven to be less than ideal. Readings taken from the same
physical location at different times of the day tend to vary significantly (often more than the specified +/-
300 meters). As mentioned earlier, it is most important that the radios’ lat/long coordinates be
RELATIVELY correct to one another. Using a GPS may compromise the repeatability of relatively correct
readings. The user may want to occasionally verify the GPS.
• When using a GPS it is necessary to physically visit each site in order to derive the lat/long coordinates. It
may be desirable to pre-program the radios before they are taken to the site to be installed. This would
require two trips to the site.
• Logistically speaking, only those with the GPS have the ability to derive lat/long coordinates. Efficient
network deployment and maintenance could be compromised or limited by the availability of the GPS.
United States Geological Survey Maps - USGS Maps
USGS maps are readily available from local maps stores, through mail order, and from USGS directly.
Each map section has lat/long coordinates printed along the borders of the map. When considering the use
of a USGS map for constructing and maintaining a UtiliNet network, here are some issues to evaluate:
• Because all USGS maps have a central reference, all derived lat/long coordinates will always be relatively
correct to one another. As mentioned earlier, this is important when considering UtiliNet’s logical routing
algorithms.
• In addition to the geographical information, USGS maps provide topological information that is helpful
when planning and maintaining a UtiliNet network. If the network is installed in an area with high ridges
and low valleys, USGS maps can be used to determine potential trouble areas as well as ideal repeater
sites.
• Maps also provide an excellent graphical representation of the network. If a radio is programmed with the
incorrect lat/long it can easily be identified in a graphical way.
For mail order USGS maps contact:
Map Link, Inc.
30 S. La Patera Lane, Unit #5
Santa Barbara, California 93117
Phone: (805) 692-6777
Toll-free phone: (800) 962-1394
Fax: (805) 692-6787
Toll-free fax: (800) 627-7768
U.S.G.S. Topo Dept. Fax: 1(800) 627-1839
Web: http://www.maplink.com
E-Mail: custserv@maplink.com
MapInfo
MapInfo® is a desktop software application that allows the user to graphically view city, county and state
maps on a computer screen. Latitude and longitude coordinates can be derived by simply positioning a
mouse cursor over the intended installation location. The approximate cost for the MapInfo application and
associated map data is $2000. When considering the use of a MapInfo for constructing and maintaining a
UtiliNet network, here are some issues to evaluate:
• MapInfo has software hooks which allow it to connect to a database server. System integrators can use
this feature to store specific installation information about many different networks. In addition to the
lat/long information, the user can store other information such as a description of the site, the installation
date, or the type of installation.
• MapInfo software can run on a laptop computer for field applications. When installing a UtiliNet radio, it
may be easier, depending on the deployment technique, for field personnel to program radios while on site.
With MapInfo, users can derive actual lat/long coordinates and program the radio while in the field.
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Although the map data is usually provided from MapInfo on a CD ROM, it can be transferred to a hard
disk.
• Additional computer hardware will be required to run the MapInfo application.
For additional information, contact MapInfo
MapInfo Corporation
One Global View
Troy, New York 12180
Tel: 518.285.6000 or 800.FASTMAP
Fax: 518.285.6070
Web: http://www.mapinfo.com
Email: webmaster@mapinfo.com
RF Considerations and System Design
Many books have been written on the subject of RF Considerations and System Design, but this section
covers the important fundamentals.
Radio Link Budget
Link Budget is a term used to describe a radio link from transmitter to receiver, and all of the factors in
between. Link budget analysis uses a simple method of allocating appropriate factors to each portion of the
link and then algebraically adding these factors. Then, the proposed link can be evaluated by how many
dB’s are left over. To analyze link budget, you must look at each component of the communication system.
Examine a sample radio link budget. Table 8.3 on page 8-9 summarizes the results.
Transmitter
For the UtiliNet product line, transmit power is +20 dBm nominally (100mW). The production minimum is
+18 dBm. It is not unusual for a radio to measure +21 to +23 dBm.
Transmit Antenna
Frequently, antenna manufacturers will not advertise the unit of measure associated with antenna gain of
their products. The commonly accepted unit of measure for antenna gain in the land-mobile industry is
dBd, which refers to dB of gain relative to a dipole. If there is a doubt, this should be confirmed with the
manufacturer. For our analysis, we need the dBi unit of measure, so a conversion factor is needed. The
conversion factor is +2.15 dB, rounded to 2 dB for this example.
Example:
A “3 dB omni-directional” type antenna is used. The antenna gain may be stated as 5 dBi. The “3 dB omni-
directional” antenna here refers to a very common, low cost antenna design consisting of a 1/4 wave
element, a phasing coil, and a 5/8 wave element, over a large ground plane. Such antennas perform well,
and are readily available from a variety of sources. It is a standard antenna for many applications, including
land mobile radios and microcellular base radios. Refer to "Use of Directional or Gain Antennas" on page
8-14 for pertinent FCC restrictions.
Ground Plane Effects
In the example above, ground plane refers to the flat, horizontal, metal chassis or enclosure to which the
antenna is secured. The ground plane works in conjunction with the antenna’s vertical element(s) to form a
complete antenna. Some types of antennas need a large ground plane to function properly, and some need
no ground plane.
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When a ground plane is required, but is not large enough, effective gain reduction results. If applicable, a
reduction of 1 to 2 dB on antenna gain would be in order for ground planes smaller than about 6 to 8 inches
along the narrowest axis.
Transmitter Transmission Line Loss
This is the equivalent cable loss of any transmission line that might be used to mount an antenna remotely
from the radio assembly. Many times the purpose for remote mounting the antenna is to get it up higher and
more in the clear. This functions to reduce the Path Loss Adder term by more than the amount of this
transmission line loss term, hence a net gain is realized. The maximum tolerable cable loss is a subjective
call. It is recommended that the cable type and length be selected such that this loss term does not exceed 3
dB. A cable loss of 1.5 dB would be a reasonable goal. For this example, assume a good quality cable is
used, and the loss at 915 MHz is 1.5 dB.
Total Path Loss
The total path loss if highly variable and can be estimated by:
• Field propagation measurements—This can provide the most valuable data, but these results can still vary
from one time to another time.
• CAD tools based on various models—Some models tend to overestimate path loss; some models tend to
underestimate path loss.
If a high gain or directional type antenna were used, a ground
plane would probably not be required because these types of
antennas are usually designed to be ground plane independent.
As a basis, first calculate free-space path attenuation. Then add a correction factor of 0 to 45 dB (or more
for very extreme conditions), depending on variables such as antenna height, terrain, foliage, or obstacles.
Free Space Path Loss
Free space assumes no obstacles blocking the path, no obstructions or significant field perturbations of any
kind present. This is the best you can hope for, but is seldom achieved unless the path is perfectly line-of-
sight. This is a useful starting point, however, for estimating path loss since it is the best achievable. Free
space attenuation at 915 MHz, for isotropic antennas at each end, is 96 dB at one mile and increases 6 dB
when distance doubles. Sometimes free space path loss is calculated differently, using dipole antennas
instead of isotropic antennas. Such is not the case here, but if it were, the 2 dB factors for dBd to dBi
antenna gain conversions would not be included.
Additional Path Loss Attenuation
For non-line-of-sight paths, an additional factor must be included that corrects for variables such as terrain,
obstacles (including buildings), foliage, people, or antenna height. This is a factor to take into account for
the installation and the path, as it is today. This factor can be derived from the works of many individuals
who have studied radio propagation and derived mathematical models: Okumura/Hata, Longley/Rice, Lee,
and others. There are various CAD tools available that are based on these measurements or algorithms.
Note that some of these CAD tools will only return the total path loss factor. Other CAD tools perform the
entire link budget analysis. For our discussion, let’s continue to consider the RF path as a sum of the
freespace path loss term and an additional path loss term. Height of both antennas, the type of environment
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along the path, distance, and other parameters can determine this factor. Typically, this factor ranges from 5
to 40 dB.
This factor, plus the free space path loss, gives total median path loss.
Example: Assume a path that is 5 miles long. One antenna is on a hill or water tank 300 ft. higher than the
surrounding area. The other antenna is on a 30 ft. support structure, for example on the rooftop of a 1 story
building. Except for the
Table 3.1 Free-Space Path Loss
hill or water tank, the terrain is considered relatively flat. The path loss adder term is -10 dB at 915 MHz,
according to the Okumura/Hata propagation prediction method using the suburban area model.
Receiver Antenna
The previously mentioned antenna considerations also apply here, including possible ground plane effects.
For this example, this is (again) a “3 dB omni-directional.”
Receiver Transmission Line Loss
The principles and goals here are the same as those for the Transmitter Transmission Line Loss term.
Receiver
Receive sensitivity for the UtiliNet product line is typically -107 to -112 dBm. Automated production tests
are performed on all deliverable radios at various frequencies, and with signal levels down to -104 dBm.
For this example, assume the receiver sensitivity is -107 dBm. This is a safe, conservative estimate for
current production radio sensitivity.
Noise Floor Factor
One of the factors that make the 800 to 900 MHz frequency band so attractive is the relatively low
equivalent noise temperature of man-made noise. For a noisy business environment, this has been estimated
to be 87 K at 915 MHz. Relative to an ambient antenna noise temperature of 298K, this translates to a noise
floor increase of 1.2 dB. Thus, we will allocate 1 dB (rounded to the nearest dB) of the link budget to
overcoming man-made noise.
Multipath Fade Factor
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For most receive signal measurements, slight changes of antenna location (on the order of 1 wavelength),
or measurements at different times, will show a short-term variance of received signal level. This is
generally due to multipath. An allowance of approximately 8 dB should be made on most radio links at 915
MHz. This is because the difference between a median received signal level and a multipath null does not
exceed 8 dB for about 80% of the measurements you could make. This factor can be reduced by one or
more diversity schemes that are available. All Cellnet spread-spectrum radios inherently employ frequency
diversity; however, it doesn’t hurt to be conservative and still include this factor. Tabulated below are 915
MHz multipath factors for other values of percent coverage. This factor varies slightly (1 to 3 dB) for
various types of environments. Values shown are for 915 MHz urban area, small city.
Table 3.2 Multipath vs. Percent Coverage
Margin of Safety
Radio systems are usually not designed to operate precisely at threshold, or even at threshold plus the
multipath factor. Usually they are designed with some extra margin. This is called a margin of safety, and is
used to account for long-term variance in the received signal level. A value of 0 to 35 dB is suggested—the
actual number depends on how conservative you are. You will use 5 dB for this example. If the actual path
could be held constant at the receiver threshold, and never varied, you would see data success rates of at
least 90%. This is because at receiver threshold, the receiver provides no more than 10% packet error rate.
Since the data link layer of the radio software only passes good packets and blocks bad packets, the data
success rate would be 100% minus 10%, or 90%. In practice, however, received signal levels vary
substantially. Rx signal levels cannot be precisely predicted. In fact, Rx signal levels vary due to such
factors as vehicular air traffic, precipitation and air temp changes, wind movement of trees and antennas,
tree growth, city growth, and population expansion. Systems are usually designed with an additional
margin of safety to overcome these and other variances for the next several years of operation.
Summary
For this example, the link budget is calculated as shown. Note that losses and margin of safety are shown as
negative numbers, since they subtract from link budget.
Table 3.3 Example Link Budget Calculation
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It is apparent that this link of 5 miles distance, under the conditions described, should be very reliable
because you were able to include a conservative multipath factor and a margin of safety, and still have the
link budget balance. If the end application allows links with less than ideal margin and reliability, much
larger distances may be spanned. A large Southern California installation consisting of thousands of
UtiliNet Series I radios with 0 dBd antennas was surveyed. The terrain varied from hilly to flat, and the
antennas varied from up high to down low. The result was that the distance between radios that were able
to communicate was an average of 5.3 miles. The distribution over ±1 standard deviation was 3 to 11
miles!
The official UtiliNet radio distance record to date (using Series I UtiliNet radios) is between Mt. Vaca (near
Sacramento, CA) and Loma Prieta Peak (South of San Jose, CA): a distance of almost 89 miles. Using 3 dB
omni-directional antennas, with cavity-type bandpass filters to protect against interference, this line-of-
sight link runs with about a 30% data success rate.
Keeping a Check on Interference
Ideally, a radio receiver should be able to process a very weak signal in the simultaneous presence of
Megawatt signals within adjacent frequency bands. Such strong adjacent signals would be rejected by the
receiver filters. In practice, however, there are practical limitations. The ratio of desired versus undesirable
signals is referred to as the Dynamic Range of the receiver. Receiver system design involves the following
trade-offs.
• Rx sensitivity versus dynamic range
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• Power consumption versus dynamic range
• Size versus dynamic range
• Cost versus dynamic range
Currently, all UtiliNet products have a receive sensitivity of about -107 to -112 dBm, with an allowable
single-tone interference level of around -20 dBm before sensitivity reduction takes place. Thus, the
dynamic range is about 90 dB. For multi-tone interference, for example several strong paging transmitters
in the area, it is recommended that the maximum interference level be limited to -30 dBm. In general, price
increases exponentially with dynamic range. For example, specialized direct-sequence spread spectrum
transceivers with 130 dB dynamic range have been built, but they sell for $60,000 each. To make this type
of solarpowered radio with battery back-up would probably cost almost as much. The consequences of
interference to the radio system will be reduced RF connectivity. This is measurable as reduced tickle
success rate and data success rate to another radio. Interference problems can be classified as either in-band
or out-of-band. Each is treated differently.
In-Band Interference
This type of interference is from devices within the same frequency range as the desired radio system, and
therefore cannot be filtered out. This is encountered if, for example, two or more UtiliNet radios are placed
at the same site to increase data handling capacity. Another example would be a UtiliNet radio and another
unlicensed Part 15 radio such as a wireless LAN radio at the same site. Usually, this type of interference is
corrected by adjusting the antenna configuration of the radios at that site.
Out-of-Band Interference
Out-of-band interference is due to radio systems on other frequencies outside the desired radio system
frequency band. These can sometimes be strong enough to cause de-sensitization or generate an excess of
significant intermodulation products.
Cellular Base Station Interference
Cellular base stations are usually not a problem unless the radio is within approximately 500 feet line-of-
sight to a cellular base station site. If this is a problem, RF filters are available. If you are in doubt, use a
spectrum analyzer to check interference levels. A reasonable goal would be to have the highest cellular
base station interference signal be no more than -30 dBm. Levels between -20 and -30 dBm will probably
be noticeable, but still not a problem. Levels above -20 dBm, especially between 890 to 894 MHz, could
cause problems if there is not 10 to 20 dB Safety Factor in the link budget.
Paging System Interference
The Radio Frequency spectrum from approximately 929.5 to 931.5 is used for paging. This application
requires transmission of enormous amounts of RF energy to penetrate buildings and houses and still be
received by the relatively inefficient antenna of a pager shielded by a person’s body. In the frequency
domain, this activity takes place just above the highest frequency of UtiliNet operation. With the
proliferation of paging systems, these signals are getting more intense and increasing in quantity. Once
again, RF filters are available to solve this problem. As with cellular, you can use a spectrum analyzer to
check for allowable interference levels. The same limits and goals apply—paging signals should ideally be
no more than -30 dBm. Levels between -20 and -30 dBm will probably be noticeable, but not a problem.
Levels above -20 dBm could cause problems if there is not a 10 to 20 dB Safety Factor in the link budget.
Performing RF Field Studies
Field surveys are necessary to prove or disprove the path predictions, as well as to provide information as
to the potential of interference from other RF transmitters that may also be located at or near any of the
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sites. Most UtiliNet surveys are accomplished by temporarily installing a UtiliNet radio at the master site
or at a repeater site and testing connectivity from the master or repeater to the remote sites in the predicted
coverage area of the master or repeater. One of the advantages to spread spectrum technology is the
license-free operation that allows installation anytime and anywhere. A second UtiliNet radio is carried to
each remote site in the predicted coverage area and powered to check connectivity. In most cases, the
UtiliNet radio’s antenna is mounted on a telescoping pole (preferably constructed from nonconductive
material) that would place the antenna as near to the final mounting height as possible. Using RadioShop
software, data is gathered from the remote radio and the master or repeater radio, assuming the two radios
connect. Use the following procedure to collect data that should be recorded for each site:
1 Make a rough sketch of the site indicating the antenna location relative to some reference structure.
2 Note any additional antennas that may be at the site and include the antenna locations on the sketch.
3 If the site is a repeater or master, ensure the master or repeater radio will communicate to the remote
radio before leaving for a remote site.
4 At the remote site, temporarily mount the antenna, power the radio and use RadioShop software to verify
RF connection to the master or repeater
5 When the radios acquire, use RadioShop to gather the site data by generating a report on each radio’s
WAN connectivity data. The WAN Nodes connectivity report provides the received signal strength
indication (RSSI), tickle success percentage, and data success percentage. Be sure to request at least 3 or 4
WAN connectivity packets from each radio before moving to the next remote site.
6 Perform a quick evaluation of the RSSI, tickle success percentage, and data success percentage numbers
to get an indication of the RF connectivity for the site. RSSI values should generally be greater than 100
units for Series I radios and greater than 130 units for radios. Tickle success percentage should exceed 40
percent and data success percentage should exceed 80 percent. In all cases the higher the numbers, the
better the connectivity.
Table 3.4 Connectivity Table
7 Repeat steps 4, 5, and 6 for each remote site in the predicted coverage area. If all of the remote sites
connect to the master or repeater, then the survey is complete and the path predictions are valid. If you
discover that one or more paths fail to establish connectivity to the master or repeater, then alternate sites
must be identified in order to secure the necessary connectivity paths.
Design Considerations
The following concepts pertaining to 900 MHz radio and UtiliNet packet radio should be kept in mind
when designing a UtiliNet network:
• Antenna height provides the best investment in terms of radiated coverage at 900 MHz.
• 900 MHz RF energy is absorbed by foliage, especially if the path is directly through an area of
concentrated foliage. Paths that angle down through the foliage instead of horizontally through the foliage
provide the best penetration.
• UtiliNet radios move packets in a forward direction in an effort to close the distance to the final
destination.
• UtiliNet radios operate in a simplex fashion. They may receive packets or transmit packets at any point in
time, but they can’t receive and transmit at the same time. This implies that multiple paths should exist into
and out of data collection/delivery points if possible.
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Glossary
Accumulator An accumulator is simply a counter in an RTU that records the number of times a contact
opens and closes or in the case of a form C contact, records the number of transitions from one contact to
the other (K to Y then K to Z in the meter world). Accumulators are most often used as interfaces into
metered values. Each accumulated pulse represents some metered quantity (KWH, gallons, barrels, etc.).
Analog An analog value is typically a measurement value obtained from a transducer. The transducer
interfaces to a system point to provide an input signal to an analog to digital converter. Transducers
typically output DC current signals in the 0 to 1 mA range or 4 to 20 mA range. The DC output signal of a
transducer is directly proportional to the input measurement value to the transducer. The transducer output
is the input to an analog to digital converter that transforms the DC signal to a digital count. Most analog
values are 11 or 12 bits plus sign. As an example, a typical voltage transducer accepts 0 to 150 volts AC
and outputs 0 to 1 mA. An eleven bit A/D converter would output a value of 1706 for an input value of 125
volts (125 = (1706
/ 2047) * 150).
Bit Oriented Protocol A bit oriented protocol is one that consists of a string of bits, 32 for example,
without a start bit, stop bit or parity bit. This type protocol was popular before microprocessors existed. The
string of individual bits was shifted using shift registers until 32 bits were captured and then the 32 bits
were evaluated for proper message content. Existing asynchronous UART hardware, such as the
transparent port, cannot capture bit oriented protocols without the possibility of dropping bits that may have
meaning in the definition of the protocol.
Bose Chaudhuri Hocquenghem (BCH)
BCH is another form of cyclic redundancy check used to detect transmission errors in master to RTU and
RTU to master communications. BCH checks are most often found in bit oriented protocols. Newer
protocols typically implement some form of CRC-16 or CRC-CCITT.
Byte Oriented Protocol A byte oriented protocol is a protocol that uses one or more 8 bit bytes where each
individual byte contains a start bit, one or two stop bits, and odd, even or no parity bit. Byte oriented
protocols are becoming the de facto standard for asynchronous communications. These protocols generally
take advantage of UART hardware for communications.
Color The color field distinguishes different addresses at a particular latitude and longitude. A WAN
address is composed of a latitude, longitude, and color. Color is used to distinguish multiple radios at the
same latitude/ longitude. In a network using domain routing, only color values 0 through 7 denote multiple
radios at the same latitude/ longitude. Color values 8 through 30 distinguish different domains, each
domain using a different color. A color value of 31 is a wildcard value and an address with a color value of
31 matches any address with the same latitude/longitude regardless of color. Radios are not programmed
with color 31. Color 31 is only used in addressing packets to radios.
Connectivity The quality of a radio’s communication with another radio.
Core In a network using domain routing, the core is the highway of routing radios that are used to route
between domains. There is only one set of core radios in a network.
Core Radio In a network using domain routing, radios are divided into “core” and “domain” radios. Core
radios are routing radios that serve as a highway to route packets between domains.
Cyclic Redundance Check (CRC)
CRC calculations provide a greater degree of security over a simple LRC. CRC checks reveal a higher
proportion of errors and are typically 16 bit values computed from the bit pattern of each byte of a message.
CRC calculations are performed by dividing the entire message by a known polynomial and retaining the
remainder as the check value. The same calculation is repeated at the receiving end and compared to the
received CRC value. Cellnet uses a CRC-CCITT (X^16 + X^12 + X^5 + 1) calculation with each packet
exchange in the network.
DCW Device control word programming language. The programs execute within devices and provide the
ability to control the device.
Domain In a network using domain routing, a domain is a localized region of connectivity. The radios
within a particular domain are well connected but do not have good connectivity to other domains. The
core is used to route between domains.
Domain Qualifying Radius Qualifying radius in domain routing is used to qualify radios as being in the
correct domain as the destination of a packet if there are separate domains with the same color. A domain
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radio qualifies as in the same domain of the packet destination if it has the same color and its geographic
location lies within the domain qualifying radius of the final destination. During a domain cul-de-sac, a
core radio that sees a domain of the same color qualifies as seeing the correct domain if it is within this
distance of the final destination.
Domain Radio In a network using domain routing, radios are divided into “core” and “domain” radios.
Domain radios are radios that have connectivity among radios in their domain, but are not good routing
choices for packets destined to other domains.
Domain Routing Domain routing is an optional routing configuration for radios with 412 or later
firmware. It serves to eliminate undesirable routing choices by forcing packets to travel through a core
highway of radios and not route through areas of poor connectivity. The network is divided into “core” and
“domain” radios.
Domains Seen In domain routing, core radios report information to other core radios of which of the 23
domain colors they have direct connectivity to and how well it can see each one (unlike latency to core, it is
not an accumulated value). This information is used by core radios to route packets in a cul-de-sac situation
with a packet addressed to a domain. A higher value for domains seen is better. Values range from 0 to 3. A
0 represent no connectivity and a 3 represents good connectivity.
Device Address The combined 10-byte WAN and LAN address of a device.
Forward Closer to the final destination of a packet.
LAN Address The 4-byte address that uniquely identifies a particular device at a radio location. A radio’s
LAN address is its serial number.
Latency to Core In domain routing, domain radios pass information among other radios of the same
domain to indicate how well they serve as paths to the core network. Latency to core is a value reporting
how well a radio has connectivity to a core radio (either directly or through other domain radios reporting
their latencies to core – in which case the latency is an accumulated value). The better the connectivity, the
lower the latency. Valuesrange from 0 to 255. This provides information for a domain radio to route
through radios with lower latency when routing to core. This is necessary because the core radios may not
be in the forward direction (the direction of the packet destination). Latency to core is used in route to core
mode when geographic routing is not used.
Longitudinal Redundancy Check (LRC)
An LRC is a simple security check applied to each byte of a message string. A typical example is
EXCLUSIVE- ORing each byte of a message. The EXCLUSIVE-OR is a common security check but not
very robust in terms of detecting bit errors in a multibyte message. Most LRC checks are used in
conjunction with parity (even or odd).
Luck A packet parameter that controls the maximum number of “hops” that a packet can travel. Each time
the packet is passed off to another radio, the luck parameter in the packet is decremented. If the luck
reaches 0 before reaching the destination, then the packet is discarded. This limits packet movement so that
packets do not hop around forever. A luck of 255 will not be decremented and will disable this limitation
for
such a packet.
MAS MAS (multiple address system) is an acronym applied to 928 - 954 MHz radio systems. Specifically,
the MAS radios operate on 1 of 40 pairs of 12.5 kHz narrowband channels between 928 and 954 MHz –
one transmit frequency and a corresponding receive frequency separated by 10 to 12 MHz. The MAS
systems perate with a single master transmitter that transmits continuously and a minimum of 4 slave radios
at RTU sites to “hear” the master message and respond if the delivered message belongs or is addressed to
the RTU. These systems have fast response times and are generally considered to be direct replacements for
dedicated telephone circuits.
Master Station The master station is the intelligence, that is typically centrally located, which orchestrates
the system. The Master Station is also the point of MMI (Man/Machine Interface). Other names for master
station might include MTU, SCADA host, etc.
Mood A packet parameter that controls the routing of packets. It specifies how a radio with the packet
decides which radio to pass the packet on to. Each of four moods can be individually specified, resulting in
sixteen combinations. The four mood settings are “persistent,” “quick,” “reliable,” and “scram.” When all
settings are off, the mood is called “courteous.” Mood is generally represented as a 4-bit field or nibble
quantity with the bits representing the mood settings as follows:
Bit 3: L3_MOOD_PERSISTENT
Bit 2: L3_MOOD_QUICK
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Bit 1: L3_MOOD_RELIABLE
Bit 0: L3_MOOD_SCRAM (not supported)
Multipoint Radios Multipoint radios are radios that may initiate data to multiple destination addresses.
Packet Parameters The parameters in a packet that control the routing, processing, and limitations of its
transmittal. The four packet parameters are mood, priority, luck, and time-to-live.
Passive Multipoint Radios Passive multipoint radios are radios that may respond with data to multiple
destination addresses, but only after being sent a request for data from that address.
Persistent A mood packet parameter that specifies to use only battery backed radios for routing (source
and destination need NOT be battery backed).
Point Radios Point radios are radios that always transmit data to the same destination address.
Priority A packet parameter that controls the processing of a packet. A higher priority packet is processed
before a lower priority packet. A user packet can have a priority from 0 through 7 (0 being the lowest
priority and 7 being the highest priority). It is not recommended that users regularly use high priorities. A
few higher prioritylevels should always be reserved and unused for diagnostics. A non-user priority 8 is
used for maintenance packets. Radios with version 413 of the firmware limit the priority of transparent
packets to a maximum of 5.
Protocol Protocol is the language used between the MTU and RTUs to communicate. Historically, each
SCADA vendor produced his own protocol to prevent competition after the initial purchase decision was
made.
Quick A mood packet parameter that specifies to factor in both tickle and data success percentage when
creating and ordering the scan lists.
Reliable A mood packet parameter that specifies to limit “hop” distance to that specified by Short Hop
Length [916BH] when creating scan lists. Radios farther than this configured distance will not be
considered for passing off a packet with this mood setting.
RTU Remote Terminal Unit, the RTU, is the slave or remote device that interfaces with field devices. The
RTU is intelligent in that it contains a microprocessor but typically performs few tasks unless instructed to
do so by the MTU.
Scan List The list of radios that qualify to route a particular packet to.
Status In the SCADA world, status refers to a digital input point to an RTU. The digital input point is in
one of two possible states at any point in time. The point is a one or zero depending on the state of a
physical contact that is directly connected to the RTU. For instance, a circuit breaker is either open or
closed, a backwater gate is either up or down, or a lift pump is on or off.
Time-To-Live A packet parameter than controls the maximum number of seconds that a packet can exist.
The time-tolive counts down and if it reaches 0 before the packet reaches its destination, the packet is
discarded.
UART Universal Asynchronous Receiver Transmitter, UART, is an acronym given to an integrated circuit
(IC) that relieves a microprocessor from some of the communications overhead involved in receiving and
transmitting asynchronous, serial, byte oriented data. Typically UARTs are programmable for multiple
baud rates, 7 or 8 data bits, 1 or 2 stop bits, and odd, even or no parity.
WAN Address The 6-byte geographic address of the radio used for routing packets through the radio
network. During the configuration process, a radio’s latitude, longitude, and color are converted into the 6-
byte address that is actually used for routing.