SCADA 4G Link Design and Measurements

Information and Technology Group Operational Technology

DESIGN STANDARD DS 42-05

SCADA 4G Link Design and Measurements

VERSION 1 REVISION 0

OCTOBER 2019

Design Standard No. DS 42-05 SCADA 4G Link Design and Measurements

Uncontrolled if Printed of 44 Ver 1 Rev 0

© Copyright Water Corporation 2019

FOREWORD

The intent of Supervisory Control and Data Acquisition (SCADA) Design Standards is to specify requirements that assure effective design and delivery of fit for purpose Water Corporation infrastructure assets for best whole-of-life value with least risk to Corporation service standards and safety. Design standards are also intended to promote uniformity of approach by asset designers, drafters and constructors to the design, construction, commissioning and delivery of water infrastructure and to the compatibility of new infrastructure with existing like infrastructure.

Design Standards draw on the asset design, management and field operational experience gained and documented by the Corporation and by the water industry generally over time. They are intended for application by Corporation staff, designers, constructors and land developers to the planning, design, construction and commissioning of Corporation infrastructure including water services provided by land developers for takeover by the Corporation.

Nothing in this Design Standard diminishes the responsibility of designers and constructors for applying the requirements of WA OSH Regulations 1996 (Division 12, Construction Industry – consultation on hazards and safety management) to the delivery of Corporation assets. Information on these statutory requirements may be viewed at the following web site location:

https://www.legislation.wa.gov.au/legislation/statutes.nsf/law_s4665.html

Enquiries relating to the technical content of a Design Standard should be directed to the SCADA Principal Engineer, Operational Technology Section. Future Design Standard changes, if any, will be issued to registered Design Standard users as and when published.

Head of Information and Technology Group

This document is prepared without the assumption of a duty of care by the Water Corporation. The document is not intended to be nor should it be relied on as a substitute for professional engineering design expertise or any other professional advice.

Users should use and reference the current version of this document.

© Copyright – Water Corporation: This standard and software is copyright. With the exception of use permitted by the Copyright Act 1968, no part may be reproduced without the written permission of the Water Corporation.

https://www.legislation.wa.gov.au/legislation/statutes.nsf/law_s4665.html




DISCLAIMER

Water Corporation accepts no liability for any loss or damage that arises from anything in the Standards/Specifications including any loss or damage that may arise due to the errors and omissions of any person. Any person or entity which relies upon the Standards/Specifications from the Water Corporation website does so that their own risk and without any right of recourse to the Water Corporation, including, but not limited to, using the Standards/Specification for works other than for or on behalf of the Water Corporation.

The Water Corporation shall not be responsible, nor liable, to any person or entity for any loss or damage suffered as a consequence of the unlawful use of, or reference to, the Standards/Specifications, including but not limited to the use of any part of the Standards/Specification without first obtaining prior express written permission from the CEO of the Water Corporation.

Any interpretation of anything in the Standards/Specifications that deviates from specific Water Corporation Project requirements must be referred to, and resolved by, reference to and for determination by the Water Corporation’s project manager and/or designer for that particular Project.




REVISION STATUS

The revision status of this standard is shown section by section below:

REVISION STATUS SECT. VER./

REV. DATE PAGES

REVISED REVISION DESCRIPTION (Section, Clause, Sub-Clause)

RVWD. APRV.

1 0/0 11.01.19 All New Version/Revision JGB RJ All 1/0 21/2/19 All New Version/Revision DB DM




DESIGN STANDARD DS 42-05 SCADA 4G Link Design and Measurements

CONTENTS Section Page

1 Overview of Standard ............................................................................................................................ 7

1.1 Purpose.................................................................................................................................................... 7

1.2 Scope........................................................................................................................................................ 7

2 Definitions and References .................................................................................................................... 8

2.1 Acronyms, Terminology and Definitions ............................................................................................. 8

2.2 References ............................................................................................................................................... 9

3 4G LTE Background Technical Information .................................................................................... 10

3.1 Receive Signal Levels to be Measured at SCADA Sites .................................................................... 10 3.1.1 Subcarriers and Reference Signals ......................................................................................................... 10 3.1.2 Receive Signal Strength Indication (RSSI) ............................................................................................ 10 3.1.3 Reference Signal Received Power (RSRP) ............................................................................................ 11 3.1.4 Reference Signal Received Quality (RSRQ) ......................................................................................... 11

3.2 Bandwidth and Latency of 4G LTE Cellular Radio Systems .......................................................... 12

3.3 Quality of Service ................................................................................................................................. 12

4 SCADA Radio Equipment to be Used ................................................................................................ 12

4.1 4G Radio Modem ................................................................................................................................. 13 4.1.1 Made and Modem .................................................................................................................................. 13 4.1.2 Frequency of Bands of Operation .......................................................................................................... 13 4.1.3 Minimum Acceptable Receive Signal Levels ........................................................................................ 14 4.1.4 Transmit Power ...................................................................................................................................... 15

4.2 4G Antennas ......................................................................................................................................... 15 4.2.1 MIMO Configuration ............................................................................................................................. 15 4.2.2 Example Antennas ................................................................................................................................. 15

5 4G LTE Radio Link Design – Desktop Works .................................................................................. 17

5.1 Design Objectives ................................................................................................................................. 17

5.2 Design Minimum Receive Signal Levels ............................................................................................ 17

5.3 Determining the Best Serving 4G LTE Cell for Connection ............................................................ 17 5.3.1 Investigating Where Nearby 4G Sites are Located ................................................................................ 17 5.3.2 Remote Site Coverage Limitations ........................................................................................................ 19 5.3.3 Path Loss Analysis ................................................................................................................................. 20 5.3.4 Choosing the Best Serving 4G RBS Site from Multiple Sites ............................................................... 21

5.4 LTE Antenna Design ........................................................................................................................... 22 5.4.1 Choosing Antenna Type and Height ...................................................................................................... 22 5.4.2 MIMO Antenna Installation Design ...................................................................................................... 23 5.4.3 Coaxial Cables ....................................................................................................................................... 23

6 Field Testing to Confirm Site Requirements ..................................................................................... 24




6.1 Test Equipment .................................................................................................................................... 24

6.2 Testing at a Site with High Modelled Signal Levels .......................................................................... 25

6.3 Testing at a Site with Moderate Modelled Signal Levels .................................................................. 25

6.4 Testing at a Site with Low Modelled Signal Levels ........................................................................... 26

6.5 Connectivity and Throughput Testing ............................................................................................... 27 6.5.1 Connectivity Testing .............................................................................................................................. 27 6.5.2 Throughput Testing ................................................................................................................................ 28

7 Other Design Considerations .............................................................................................................. 28

7.1 Fall-Back and Handover ..................................................................................................................... 28

7.2 Interfering Signals on the Uplink Path .............................................................................................. 29

7.3 Modem Security ................................................................................................................................... 29

8 Typical 4G Antenna Types and Installation Examples for Fixed Subscribers .............................. 30

8.1 Shark Fin and Low Profile Antennas ................................................................................................. 30

8.2 Collinear Antennas .............................................................................................................................. 31

8.3 High Gain Grid Pac Antennas ............................................................................................................ 33

8.4 Long Periodic Antennas ...................................................................................................................... 34

8.5 Panel MIMO Antennas ........................................................................................................................ 35

Appendix A VSCADA Site – Field 4G Modem Testing Record Worksheet ....................................................... 37

Appendix B Additional 4G LTE Background Information .................................................................................. 40

Appendix B.1 4G LTE Basic Parameters ............................................................................................................... 40

Appendix B.2 LTE – Communication Channels ................................................................................................... 42

Appendix B.3 4G Operating Frequency and Band Numbers ............................................................................... 43




1 Overview of Standard

1.1 Purpose The purpose of this standard is to define the radio design requirements and measurement techniques to determine suitable connectivity for Water Corporation remote Supervisory Control and Data Acquisition (SCADA) field sites into the SCADA central network via the Telstra’s 4th Generation (4G) Long Term Evolution (LTE) cellular network.

1.2 Scope This standard shall be applied to the design of SCADA radio installations operating on the Telstra 4G LTE network.

Telstra’s 4G LTE network is deployed in Urban, Suburban and Rural environments. Where sufficient coverage exists to enable a reliable connection, the Water Corporation leverage on this system to provide IP connectivity to the SCADA Units deployed in the field and also for field engineers to connect back to the Water Corporations corporate WAN.

This standard focuses on what is required to best connect to the Telstra 4G LTE network base stations via a Sierra Wireless AirLink RV50 4G wireless modem from the SCADA field unit. The focus is on designing a radio link that will provide reliable data connectivity from the field SCADA unit back to the Water Corporation central SCADA site.

Telstra currently operate their 4G LTE cellular network in the 700MHz, 1800 MHz and 2600MHz spectrum bands. As these different frequencies impact coverage and network capacity, consideration will also be given to which band is chosen in which environment.

Antenna selection, height requirements, configuration and radiation direction are also covered in detail in order to help achieve a reliable radio path.

For the purposes of this standard it is assumed that the Sierra Wireless AirLink RV50 modems have been pre-configured by the Water Corporation according to their requirements. Configuration and installation requirements and instructions are included in detail in the following two manuals:

AirLink RV50 – Hardware User Guide (Revision 4.0) and

AirLink RV50 – ALEOS 4.11.2 Software Configuration User Guide (Rev 1).

These configuration and installation requirements for the modem are not repeated in this standard (other than some relevant Radio Frequency (RF) design data). This standard focuses on the requirements outside of the modem and how to establish a suitable 4G link with a Telstra 4G RBS site.




2 Definitions and References

2.1 Acronyms, Terminology and Definitions The following Table 2-1 provides meanings for acronyms and other terminology used throughout this standard.

Table 2-1: Acronyms, Terminology and Definitions

Acronym / Term Definition 3GPP 3rd Generation Partnership Project 3G 3rd Generation cellular mobile phone technology 4G 4th Generation Long Term Evolution (LTE). 4G is the cellular mobile phone

technology standard developed by the 3rd Generation Partnership Project (3GPP)

ACMA Australian Communications and Media Authority AGD66 Australian Geodetic Datum 1966 BER Bit Error Rate C/I Carrier to Interference ratio Design Fade Margin The fade margin applicable to any RSL calculated during design. E-UTRA Evolved - UMTS Terrestrial Radio Access (the 3GPP air interface used for

LTE) EIRP Effective Isotropic Radiated Power FDD Frequency Division Duplexing Fade Margin An additional RF signal allowance (safety margin) that provides for sufficient

system gain or sensitivity to accommodate expected or unexpected fading. Feeder Cable A cable that connects the antenna to the radio system Free Space Propagation

Free space propagation occurs when the transmitting and receiving antennas have a clear, unobstructed path between them.

Path Loss Calculated radio signal path loss between the transmitter and the Receiver. LAN Local Area Network LPDA Log Periodic Dipole Antenna LTE Long Term Evolution (includes the 4G and 5G standards) LOS Line of Site MAC Media Access Control Mbps Mega Bits per second MIMO Multi In Multi Out MHz Mega Hertz NRB Number of Resource Blocks Operational Fade Margin

The fade margin applicable to a working system RSL.

OFDM Orthogonal Frequency Division Multiplexing Propagation Measurement

Measurement of RSL on a radio path using radio test equipment.

QoS Quality of Service

http://en.wikipedia.org/wiki/System

http://en.wikipedia.org/wiki/Gain

http://en.wikipedia.org/wiki/Sensitivity_(electronics)

http://en.wikipedia.org/wiki/Fading




Acronym / Term Definition RACH Random Access Channel RB Resource blocks RBS Radio Base Station (4G LTE in this document) RLC Radio Link Control RSL Receive Signal Level (at the radio receiver input) RSRP Reference Signal Receive Power RSRQ Reference Signal Receive Quality RSSI Receive Signal Strength Indication RTU Remote Terminal Unit RX Sensitivity Radio Receiver Sensitivity SCADA Supervisory Control And Data Acquisition Serving Cell The serving sector of a Cellular Radio site in which a UE has a connection. SC-FDMA Single Carrier Frequency Division Multiple Access SNMP Simple Network Management Protocol SNR Signal to Noise Ratio TTI Transmission Time Interval UE User Equipment (in this case the radio modem) WAN Wide Area Network

2.2 References The following Table 2-2 provides a list of reference documents used during the production of this standard:

Table 2-2: Reference Documents

Title Author Publisher Date AirLink RV50 – Hardware User Guide (Revision 4.0)

Not Specified Sierra Wireless March 2018

AirLink RV50 – ALEOS 4.11.2 Software Configuration User Guide (Rev 1)

Not Specified Sierra Wireless November 2018

PM-9222304-v4 PTM Steven Alilovic Water Corporation

02 July 2013

PM#16977329 Water Corporation SCADA Approved Equipment List

A&C Strategy Advisor SCADA Branch

Water Corporation

Ver date 5/2/2019

Specifications Series TS 36 36101-c30_s00-07 36101-c30_s08-10

Not Specified 3rd Generation Partnership Project (3GPP)

March 2014

Introduction to MIMO 07.2009-1MA142_0e

Schindler, Schulz Rhode & Schwarz July 2009

LTE RSSI, RSRP and RSRQ Measurement

Not Specified CableFree Laroccasolutions

2018




3 4G LTE Background Technical Information The following section provides some relevant background technical information on 4G LTE that may be useful when using this standard to design and implement 4G links from the SCADA 4G radio modem (also known as the “User Equipment” (UE) or “Subscriber”) to the Telstra 4G LTE basestation.

This section is not intended as a tutorial on LTE, but rather to provide sufficient technical data to ensure this standard can be properly applied by engineers and technicians.

Additional background technical information is provided in Appendix A. The reader should refer to the many on-line resources to learn more of LTE basics if required.

3.1 Receive Signal Levels to be Measured at SCADA Sites There are three measurements that can be made at the UE installed into SCADA field unit site. The following describes each and its relevance to the required outcomes.

3.1.1 Subcarriers and Reference Signals A 4G LTE downlink is divided into subcarriers. A 5 MHz bandwidth downlink, contains 300 x 15kHz subcarriers. And of those subcarriers, one in three carry LTE reference signals. In other words, of the 300 subcarriers, 100 transmit periodic reference signals. Therefore, a 10MHz bandwidth downlink will transmit 600 subcarriers and 200 of these will contain periodic reference signals.

A Resource Block (RB) is the smallest unit of resources that can be allocated to a user. The resource block is 180 kHz wide in frequency and 1 slot long in time. In frequency, a resource block is 12 x 15 kHz subcarriers wide. Two time slots are transmitted in 1ms elapsed time (known as a Sub-Frame), and each time slot has 7 individual modulation instances of each subcarrier (known as OFDM Symbols), or 7 x 12 symbols per resource block.

The Reference Signal is one Symbol and there are four Reference Symbols sent per resource block. Note that RSRP is sometimes referred to as Reference Symbol Received Power.

The following table provides a summary of resource blocks and subcarriers for each bandwidth allocation used in Australia:

Table 3-1: LTE Resource Block and Subcarrier Allocations for Various Bandwidths

Bandwidth Resource Blocks Subcarriers (Downlink)

Subcarriers (Uplink)

5 MHz 25 301 300 10 MHz 50 601 600 15 MHz 75 901 900 20 MHz 100 1201 1200

3.1.2 Receive Signal Strength Indication (RSSI) RSSI is a measurement of the total received wide-band power, where it measures across all the LTE symbols within the allocated bandwidth, including all interference and thermal noise. Represented as a formula it would be:

RSSI = wideband power = noise + serving cell power + interference power




RSSI is not reported to the eNodeB by UE. It can simply be computed from Reference Signal Receive Quality (RSRQ) and Reference Signal Receive Power (RSRP) that are, instead, reported by the UE. This equates as follows:

RSRQ = RSRP / (RSSI/N): Where N is number of Physical resource blocks

RSSI was the RF measurement used mostly for 3G and earlier analogue radio technologies.

As such then, RSSI will not be measured as part of the 4G link design and implementation.

3.1.3 Reference Signal Received Power (RSRP) RSRP is an LTE specific metric that averages the RF power in all reference signal subcarriers in the transmitted carrier.

More specifically, RSRP is the average power of Resource Elements that carry cell specific Reference Signals over the entire bandwidth, so RSRP is only measured in the symbols carrying Reference Signals. There are 4 Reference Symbols (Signals) inserted into each resource block.

Hence RSRP is the average received power of the reference symbols in a resource block. The UE measures the power of multiple resource elements used to transfer the reference signal but then takes an average of them rather than summing them.

The normal reporting range of RSRP from a UE is -44 to -140 dBm.

RSRP does a better job of measuring signal power from a specific sector while potentially excluding noise and interference from other sectors.

RSRP levels for usable signal typically range from about -75 dBm close in to an LTE cell site to -120 dBm at the edge of LTE coverage (although some UEs will continue to demodulate data down to as low -130dBm RSRP).

3.1.4 Reference Signal Received Quality (RSRQ) RSRQ is a Carrier to Interferer (C/I) measurement and it indicates the quality of the received reference signal power.

RSRQ levels are calculated based on both RSRP and RSSI measurements by the radio modem.

The RSRQ measurement provides additional information when RSRP is not sufficient to make a reliable cell reselection decision.

In circumstances were the signal level quality is determined by the UE to be worse than the next best serving cell, a cell reselection will occur (Handover). A handover will occur if the serving cell fails, is switched off or the RSRP and RSRQ levels drop below the level of the next best serving cell.

In the handover process the LTE specification provides the flexibility of using RSRP, RSRQ, or both. These parameters are non-user configurable and the UE controls the handover process.

RSRQ can sometimes be misleading if used to make a judgement call on best serving cell sector. For example, RSRQ could go low for short periods of high external noise. A car ignition, WiFi unit close by, mobile phone close by with Bluetooth active, electric motor running from a pump, lightning storms, high atmospheric static levels etc will all cause high ambient noise and interference that will reduce the RSRQ.




So the RSRQ measurement may favour a particular RBS or sector based on arbitrary external noise levels. Hence, although RSRQ is a useful measurement, RSRP is the normally the measurement that should be used first for making decisions on which RBS to use.

3.2 Bandwidth and Latency of 4G LTE Cellular Radio Systems System latency can be measured as a one-way or round trip path of the signal. A round trip is the common measurement as it covers the time from the initiation of a data session on the UE through the network on the uplink and back via the downlink of the network until a response is received from the targeted site. For example, the time between when a request to load a webpage is made to when that webpage begins to load. In addition to increased data rates, the latency enhancements of 4G compared to 3G provide a significant improvement in the data speeds.

With 3G networks, a subscriber can expect a two-second or longer delay to setup the first connection, and then between 75 and 150 ms roundtrip latency afterwards. With LTE’s all IP architecture, the initial data packet connection is much faster, typically 50 ms, and then between 12-15 ms roundtrip latency with the RBS once connection is established (latency with external network or the internet will be longer depending on the delays in those networks). LTE’s roundtrip latency compares favourably to the typical latency on today’s fixed line broadband infrastructure, delivering an almost instantaneous response. For session initiated connections the performance benefits gained from the faster setup time increases overall data throughput and allows for faster software upgrades of field equipment when required.

Once the SCADA radio link is established with Telstra, latency will be tested from the field SCADA unit to the central SCADA and return. This shall be tested using Internet Control Message Protocol (ICMP) Ping tools (refer to section 6.5.1).

3.3 Quality of Service Quality of Service (QoS) in networks is the ability of the network to enforce different priorities for different application types, subscribers, or data sessions, while guaranteeing a certain level of performance to a data session.

4G LTE as an all IP network defines QoS to not only guarantee the quality of a service but also support different levels of services for other latency or bit-rate sensitive applications. LTE has adopted a class-based Quality of Service model which is simple and provides operators with an effective and simple way to differentiate between services and support users with varying levels of service quality.

The Water Corporation may determine that it would be useful to apply a high QoS to certain important SCADA data. Normally Telstra only have this service available on certain service types, which may not be available where Water Corporation require them. For further details on the availability of this option in certain areas Telstra will need to be contacted directly.

4 SCADA Radio Equipment to be Used The following section defines the 4G radio equipment that shall be used for design and implementation of 4G radio links into the Telstra 4G network for Water Corporation SCADA field sites.




4.1 4G Radio Modem

4.1.1 Made and Modem The following equipment has been specified by the Water Corporation as the 4G LTE radio modem to be used for SCADA applications:

Sierra Wireless AirLink RV50 LTE radio modem.

This is to replace the modem that has been previously used for 4G reception sites, the Sierra Wireless AirLink GX440.

At the time of writing this standard no other 4G modems have been identified for use. Therefore, an alternative manufacturer and/or model of 4G LTE modems shall only be used if approved in writing by the Principal SCADA Engineer.

4.1.2 Frequency of Bands of Operation The currently published AirLink RV50 Hardware User Guide (Revision 4.0, March 2018) specifies the AirLink RV50 radio modem operates in the following relevant Australian LTE defined RF bands.

Table 4-1: AirLink RV50 Frequency Bands of Operation

Standard Band Frequency

LTE 4G Band 1 Tx: 1920-1980MHz

Rx: 2110-2170MHz


Rx: 1805-1880MHz


Rx: 869-894MHz


Rx: 2620-2690MHz


Rx: 925-960MHz


Rx: 860-875MHz


Rx: 875-890MHz

LTE 4G Band 21 Tx: 1447.9-1462.9MHz

Rx: 1495.9-1510.9MHz


Rx: 758-803MHz

LTE 4G Band 38 Tx/RX: 2570-2620MHz (TDD)







Standard Band Frequency

3G Band 1 Tx: 1920-1980MHz

Rx: 2110-2170MHz

3G Band 5 Tx: 824-849MHz

Rx: 869-894MHz


Rx: 875-885MHz


Rx: 925-960MHz

3G Band 9 Tx: 1749.9-1784.9MHz

Rx: 1844.9-1879.9MHz


Rx: 875-890MHz

4.1.3 Minimum Acceptable Receive Signal Levels The Sierra Wireless has recommended minimum receiver levels for adequate performance of the Airlink RV50 radio modem, specified in terms of RSRP and RSRQ. This is as measured at the RF input port to the modem. The following signal levels are specified in the user guide.

However, the Water Corporation requires that the slightly more conservative signal levels shown in the adjacent columns shall be used as the design guide.

Table 4-2: Acceptable RSRP Signal Levels

Sierra Wireless’s Stated Evaluation Water Corporation’s Preference

RSRP Reading Signal Strength Evaluation

RSRP Reading Signal Strength Evaluation

> -95dBm Good > -95dBm Good

-95dBm to -115dBm Fair -95dBm to -110dBm Acceptable

-116dBm to -1000dBm Poor -110dBm to -115dBm Fair

< -1000dBm Inadequate < -116dBm to -125dBm Poor

< -125dBm Inadequate

Note that the actual reading used needs to have been obtained by averaging the RSRP over a period of time. Ultimately the longer the better, but a minimum of 15 minutes shall be used.

Therefore, the minimum design RSRP level shall be -110dBm as measured and averaged over a minimum of 15 minutes.

The following Table 4-3 provides acceptable RSRQ readings:

Table 4-3: Acceptable RSRQ Signal Reading

Sierra Wireless’s Stated Evaluation RSRQ Reading Signal Strength Evaluation > -9 dB Good




-9 dB to -12 dB Fair (Acceptable)

< -12 dB Poor

The RSRP reading should be used as the determining factor for acceptable coverage, and RSRQ used as a check that the SCADA site is not in a location with excessive external noise and interference.

The preferred minimum design RSRQ level shall be -12dB as measured and averaged over a minimum of 15 minutes.

4.1.4 Transmit Power Sierra Wireless has specified the TX power levels for all the 4G and 3G bands noted in section 4.1.2 from the AirLink RV50 radio modem as +23dBm +/-1dBm.

This power level shall be used for all the path loss calculations.

4.2 4G Antennas There are a number of different options for antenna types and configuration that can be used for the 4G radio link to a Telstra 4G RBS. The decision as to what type and configuration should be used depends ultimately on the required gain and the signal path loss to the base station.

4.2.1 MIMO Configuration The use of MIMO antenna configuration shall be used on the RV 50 radio modem. This will maximize the performance of the radio modem and improve the performance of the radio link.

The RV50 has two MIMO antenna ports providing for a 2x2 MIMO antenna configuration.

The antenna configuration can be achieved using a single antenna with two MIMO ports or using two separate antennas. As a general rule using separate antennas will provide a more optimised configuration in the right environment.

For line-of-sight links, MIMO antenna configurations generally make very little difference to the overall performance. For non-line-of-sight links, particularly where there is significant multipathing, the MIMO antenna configuration will provide improved performance. In this situation MIMO antennas in 4G LTE networks provide the following benefits:

Enhanced data throughput;

Enhance the Carrier/Interference ratios at the Modem receiver by effectively reducing interference in the space domain:

Enhanced signal reception through directional array gain;

Extended cell coverage; and

Enhanced 4G system capacity.

4.2.2 Example Antennas The table below provides a list of some suitable antennas for SCADA field sites. These antennas, other than the noted 1800 MHz Grid antennas, are all wideband and have the capability to fall back to Telstra NextG (3G) basestations.




The antennas noted with a * are on the Water Corporation preferred equipment list (as at February 2019). Other antennas can be offered, but approval shall be obtained from the Principal SCADA Engineer before proceeding.

Table 4-4: Typical LTE Antennas available from Australian Suppliers

Antenna Manufacturer /

Distributor

Part Number

Band (Frequency

Range) Antenna Gain Notes

Telco Antennas *

Taoglas Storm MA412

700-3600MHz 4G - 700MHz 3.54dBi 3G - 850MHz 4.07dBi 3G - 900MHz 4.13dBi 4G - 1800MHz 4.67dBi 3G - 2100MHz 6.69dBi 4G - 2600MHz 8.11dBi

Low profile vandal proof cabinet mount (refer to Figure 8-2) MIMO Configured

RFI * TLA 4100 TLA 4200

800-960 MHz 1710-2700 MHz

5dBi Sharkfin, does not offer MIMO (refer to Figure 8-1)

Telco Antennas *

SKU: OMNI700-2700

700-2700MHz 4G - 700MHz 5dBi 3G - 850MHz 6dBi 3G - 900MHz 5dBi 4G - 1800MHz 8.4dBi 3G - 2100MHz 9.4dBi 4G - 2600MHz 8dBi

Pole or Roof Mounted 4GX collinear antenna without MIMO

Panorama antennas *

WMM8G-7-27-03NJ

700-2700MHz 698-960 MHz 6dBi 1710-2170 MHz 9dBi 2396-2700 MHz 6dBi

Fringe 700MHz, 850MHz only

Comset /RFI CM-LTE-001 LTE MIMO

790-960MHz. 1710-2170MHz 2500-2700MHz

790-960MHz 2.4dBi 1710-2170MHz 5dBi 2500-2700MHz 6dBi

Omni Directional MIMO High return loss overall, ±45 degree polarisation.

RFI LTE-XPOL-002V MIMO

790-960MHz 1710-2170MHz 2500-2700MHz

790-960MHz 8.3dBi 1710-2170MHz 6.9dBi 2500-2700MHz 9dBi

Directional MIMO ±45 degree polarisation Good return loss at 700 MHz 1800 MHz and 2600 MHz

Telco Antennas 4G17GRID-MIMO

1800 MHz Only 17dBi For Rural sites with a significant path loss. Highly directional requires cross polarised mounting. 45 and 135 Degrees. Not suitable for Next G. (Refer to Figure 8-4)

Telco Antennas RFI Dual Polarity LPDA Antenna

700-3000MHz Nominal 8dBi Wide band log periodic dipole antennas, suitable if there is clutter from trees close by and no other means of




Antenna Manufacturer /

Distributor

Part Number

Band (Frequency

Range) Antenna Gain Notes

achieving a clear line of site to the serving cell.

5 4G LTE Radio Link Design – Desktop Works The following requirements shall apply to the desktop works associated with the design of 4G LTE Water Corporation SCADA radio systems.

5.1 Design Objectives The design of a 4G LTE radio link shall achieve the following objectives:

Achieve reliable data radio connection to the Water Corporation SCADA and Corporate WANs;

Minimise the cost of antenna support structures whilst achieving the specified design minimum RSRP and RSRQ requirements; and

Satisfy all specified performance objectives in this standard.

5.2 Design Minimum Receive Signal Levels The 4G Link shall be designed to meet the minimum signal levels noted in section 3.1. The subjective evaluation of “Acceptable” is used. Therefore, as noted previously:

The minimum average RSRP shall be -110dBm when measured and averaged over 15 minutes; and

The minimum average RSRQ shall be -12dB when measure and averaged over 15 minutes.

5.3 Determining the Best Serving 4G LTE Cell for Connection Before heading to site to test for 4G coverage at the SCADA site, it may be beneficial to carry out a desktop study to determine where the potential Telstra 4G RBS sites are located and the distance and quality of the RF path from the RBS/s to the SCADA field unit.

There are two components to the desktop study; investigation to determine location of nearby 4G sites and then modelled path loss analysis of the RF path.

The desktop investigation and pathloss analysis will be more relevant in rural or semi-urban areas where the RBS sites are significantly separated. In built up Urban areas there will normally be more than one close-by 4G RBS site to choose from.

5.3.1 Investigating Where Nearby 4G Sites are Located It may be possible to visually locate nearby Telstra RBS sites. Noting down their approximately location, and their distance and direction from SCADA field site, will assist in determining their location on a digital map when path loss modelling is carried out.

If locations of 4G LTE radio sites are unknown, the ACMA database can be searched to show base station locations and available radio technologies. The web site is located at:

http://web.acma.gov.au/pls/radcom/register_search.main_page.

• Searches can be performed for the following criteria:

http://web.acma.gov.au/pls/radcom/register_search.main_page




• Spectrum License By Category;

• Spectrum License Image Search;

• Site Search by Latitude and Longitude (AGD66) or postcode locations;

• Assignment/Frequency range searches; and

• Emission designators.

This can prove difficult to use at times, so the following page helps to more easily pin point the location of Telstra towers

http://web.acma.gov.au/pls/radcom/site_proximity.main_page

When one or more of nearby 4G LTE RBS sites are identified, the coordinates can be mapped in a basic GIS tool such as Google Earth to display the location of cellular sites relevant to the SCADA field location.

Once you have located the nearest Telstra site, you can click on it to get details such as (click on the blue URL links to dig deeper into the website for more details):

• RBS site latitude and longitude (or easting and northing);

• The 4G and/3G frequencies being used;

• The azimuth of each RBS antenna;

• The bandwidth of the transmission;

• The transmit power (EIRP);

• The antenna height;

• Feeder loss;

• Antenna Gain;

• Antenna Polarisation;

• Antenna Tilt; and

• Bearing/s from the SCADA site to the Telstra RBS/s.

These parameters can be used to determine approximate coverage from that site in programs such as Mentum Planet or Path Loss 5.

It is also worth noting that a very rough approximation of where coverage may be expected from that site/sector can be drawn on the screen by clicking on the required sector and then licking on the “Go” button next to “Viewshed”. This is shown in Figure 5-1 below.

It is important to note that these viewshed coverage maps are very approximate and should under no circumstances be used a basis of design or financial commitment, but rather as a rough guide as to the next steps, or choosing one site from multiple sites to work on first.

http://web.acma.gov.au/pls/radcom/site_proximity.main_page




Figure 5-1: Producing an Approximate Viewshed of Coverage from the ACMA Website

5.3.2 Remote Site Coverage Limitations Telstra can configure their RBS sites with varying maximum cell ranges to suit the environment in which it will be operating and the expected traffic levels. This is particularly useful in rural areas for providing extended coverage areas but where capacity requirements are low.

It is possible that even when the available signal strength meets the radio modem signal level requirements, if the SCADA site is outside the maximum designed cell radius, connectivity will not be possible.

The maximum cell radius is determined when the UE tries to register to the 4G LTE RBS using the registration process through the Random Access Channel (RACH).

Table 5-1 below indicates the maximum cell range. This is determined by the preamble format when the UE tries to register with the RBS. For information purposes preamble 0 to 3 are valid for Telstra FDD systems. Format 4 is reserved for TDD systems.




If the link designer has doubts as to the effectiveness of a possible link they will need to liaise with their Water Corporation Telstra account manager for further information regarding cell radius at particular remote rural locations chosen for SCADA site connectivity.

Table 5-1: Maximum RBS Coverage Radius Based on Preamble Channel Formats

5.3.3 Path Loss Analysis In rural or semi-urban areas where an RBS being proposed as a serving cell is not visible, or there may be clutter which stops direct visibility, completing a desktop propagation analysis will provide the path distances to the proposed RBS candidates, path loss figures and hence expected RSRP receive signal levels and overall performance.

To determine the best serving Telstra 4G basestation, a desk top study can be completed using the technical configuration and performance values obtained from the ACMA website and using typical LTE RBS and UE performance parameters.

A reputable coverage modelling tool such as Mentum Planet or Path Loss™ should be used to ensure that the performance characteristics are modelled correctly and a variety of useful and accurate data is produced.

Completing the desk top propagation analysis for 4G sites that are not visible from the SCADA unit before attending a site visit is recommended. The analysis will produce results that provide suitable candidate 4G RBS sites and expected RSRP values against which to compare when doing field testing.

Due to the higher density of population in urban areas, Telstra will tend to have higher signal levels from the basestations as they will install more RBS’s for increased traffic capacity. It is prudent to note that despite there being a higher density of RBS sites there will still be areas with weak signal levels and dead spots which may/may-not show up in a modelled coverage analysis. The only solution will be to visit site and try different antenna scenarios and heights.

Modelling in programs such as Mentum Planet or Path Loss is complex and needs to be performed by an engineer who is experienced with the program and the corresponding LTE module in order to guarantee that the output is of good accuracy.

The following is a list of the minimum data required in order to run a reasonably accurate coverage analysis of the SCADA field site from 4G RBS sites. Note that a number of these parameters will not be available from the ACMA website, so a the design engineer will need to use typical values from other LTE designs in this instance.

• Digital terrain data (can be obtained from http://elevation.fsdf.org.au/) to highest resolution available;

• Clutter information for the surrounding environment including tree density, height, type, area etc;




• Latitude/ Longitude or Easting/Northings of the serving cell site(s) and the SCADA field unit location;

• TX power or EIRP of the 4G LTE RBS serving sector;

• Antenna digital radiation pattern (normally available from manufacturer);

• Receiver noise figure for 4G RBS sector;

• Antenna height on Mast;

• Cable length from eNodeB to antenna and cable loss;

• Tx power and noise figure for UE;

• Frequency and Bandwidth of proposed serving cell in the area. (from ACMA database);

• Antenna gain of radio modem antenna – will depend on receive levels at the SCADA site (refer to section 5.4);

• Preferred antenna heights for radio modem antenna – model with 2 metres, and if this is insufficient move up to 4 metres and then 6 metres. Higher may be required, and should be modelled in 2 metre increments;

• Feeder cable loss used at SCADA field site;

• Proposed minimum receive signal level at Radio Modem – in this case -110dBm RSRP;

• Typical LTE equipment configuration parameters such as Modulation Coding Scheme (MCS) curves, correlation factors between sectors, etc

• A suitable propagation model (eg Predict 4.0); and

• A suitable agreed signal confidence level (for example a cell edge signal probability of 90%).

The following is an example of the type of data that can be extracted from a desktop coverage analysis using Mentum Planet or similar:

Table 5-2: Example of Data Obtained from LTE Coverage Modelling using Mentum Planet

Lat LongSCADA Site

Name

Uplink Max Achievable Data Rate

(Mbps)

Uplink Average

Data Rate (Mbps)

Downlink Max

Achievable Data Rate

(Mbps)

Downlink Average

Data Rate (Mbps)

RSRP Best

Server(dBm)

Best Server_Sector No.

Best Server

RSSI(dBm)

2nd Best Server_Sector No.

2nd Best Server

RSSI (dBm)

3rd Best Server_ Sector No.

3rd Best Server

RSSI(dBm)

PDSCH C/(N+I)

(dB)-25.927454 149.46889 Example 1 0.0883137 0.4061704 2.462966 11.07734 -119.834 Telstra 1 _ 2 -99.83215 Telstra 3 _ 1 -102.7741 Telstra 1 _ 2 -116.4525 5.218665-26.254195 149.82529 Example 2 0.1105747 0.6003148 2.462966 11.68176 -119.1015 Telstra 2 _ 3 -99.10276 Telstra 1 _ 3 -101.7731 Telstra 3 _ 3 -103.2533 5.465865

It is important to note the type, height, material density, coverage area and water susceptibility of all nearby clutter. For example trees or shrubs which are in close proximity to the proposed antenna location will attenuate the RF signal level to some degree. During heavy rain showers, some densely populated trees bodies could add up to 20dB attenuation to the radio path depending on the frequency, thickness, type, rainfall quantity etc. Modelling software such as Mentum Planet or Path Loss has the facility to calculate the effects of clutter on the signal and needs to be accounted for in the modelling.

5.3.4 Choosing the Best Serving 4G RBS Site from Multiple Sites If there is more than one 4G RBS that is providing sufficient signal level, then the best serving cell should be chosen given the following criteria, in order of importance:




• The RBS site with the minimum clutter on the RF path; that is with minimum obstruction from the trees, buildings, water tanks etc;

• Strongest RSRP Signal Level;

• Best RSRQ Reading;

• Closest distance; and

• Lowest frequency.

5.4 LTE Antenna Design The antenna chosen will depend on the RSRP signal level being received at the SCADA unit. The desktop analysis will provide a good indication of what to expect.

5.4.1 Choosing Antenna Type and Height The preference should always be to use an omnidirectional antenna if possible. This will enable the SCADA site to redirect to a second best serving sector (assuming there is one available) if the link to the main site should fail.

There are fundamentally three different design scenarios when deciding on which antenna to use:

• Acceptable RSRP signal modelled at 2 metres:

If the desktop analysis shows that there is an acceptable signal level (greater than -110dBm RSRP at 2 metres antenna height, then an Omnidirectional Shark-fin or Low Profile type antenna can be installed on top of the SCADA cabinet.

• Acceptable RSRP signal modelled at 6 metres:

If the desktop analysis shows that there is an acceptable signal level (greater than -110dBm RSRP at 6 metres antenna height (but unacceptable at 2 metres), then an Omnidirectional Co-linear type antenna can be installed on top of a 6 metre pole that is attached to the SCADA cabinet or installed as a separate stand alone structure.

• Unacceptable RSRP signal modelled at 6 metres:

If the desktop analysis shows that there is an unacceptable signal level (less than -110dBm RSRP at 6 metres antenna height, then an iterative approach to the modelling analysis is required. The first iteration should be to model with a high gain Yagi or Grid Pac antennas pointing directly at the RBS site. If this is still not producing sufficient signal level then there should be an iterative approach to raising the pole in 2 metre sections until sufficient signal level is achieved.

Of course, there will be a limit to what the pole height can be before it becomes uneconomic to proceed with 4G or 3G. This will be project dependant, and should be confirmed with the Project Manager, but will most likely be approximately 25metres. Alternative communications technologies such as satellite may then need to be considered.

It is not recommended to have the antenna at a height greater than required to achieve the required signal levels. The longer the feeder cable run then the greater the loss, which in turn requires more expensive low loss cable to be installed to counter the additional loss. However, the biggest cost will be in installing the larger antenna support structure (the cost of which tend to go up exponentially with height). In addition, the designer needs to be sure that he is not




overloading the Telstra RBS site with too much signal (refer to section 7.2 for further information on this requirement).

5.4.2 MIMO Antenna Installation Design As noted previously, MIMO antennas shall be used for LTE installations. Most commercially available MIMO antennas are built as one unit, with two internal antennas and two coaxial cable connections.

Where possible two separate antennas should be used as this allows greater spacing and more effective MIMO operation. It also allows higher gain antennas to be used if required.

If two separate antennas are to be used, for example two Yagis, they normally need to be installed at 90degrees out of phase with each other. To align with the RBS antennas (so the RBS and UE antennas are in the same phase) one should be installed at +45degrees and the other +135degrees. The photos in Figure 8-4 and Figure 8-5 illustrate how this is achieved.

The following table provides the optimal separation distances between MIMO antennas that should be used for the installation designs where possible.

Table 5-3: Antenna Separation Distances for MIMO Installations

Service Frequency

(MHz) Wavelength

(mm)

Best Antenna Separation

½ λ (mm)

Good Antenna Separation

¼ λ (mm)

LTE 700 428 214 107 LTE 800 375 187 94 LTE 900 333 167 83 LTE 1800 167 83 42 LTE 2100 143 71 36 LTE 2600 115 58 29 3G 850 353 176 88 3G 900 333 167 83 3G 1900 158 79 39 3G 2100 143 71 36

5.4.3 Coaxial Cables The Designer shall confirm with the Water Corporation SCADA Engineer what coaxial cable is preferred for any installation configuration.

Under normal circumstances the following cables are examples of the types of cable that could be used for the different scenarios, depending on approval from the Water Corporation.

• Shark Fin or Low Profile Mounted on SCADA Cabinet:

o RG 58 (low loss version)

o LMR 300

o RG214/U

• Pole Mounted Colinear or Directional Antennas:




o LMR 400

o LDF 450

6 Field Testing to Confirm Site Requirements Once the desktop design is complete the designer shall go to site to carry out signal level testing to confirm that the desktop design will work correctly.

In order to define how the field testing should be carried out, the range of desktop predicted received signal levels at the SCADA unit are broken into three scenarios;

1. High average levels that are well above the minimum receive signal level;

2. Moderate average levels that are near but above the minimum receive signal level; and

3. Low average levels that are at or below the minimum receive signal level.

The ranges have been used below to dictate what types of site testing are required for measuring 4G RF signal levels.

Once the signal level has been established then some simple connectivity and throughput testing shall be carried out.

A test record sheet is provided in Appendix A of this standard. The tester shall fill this sheet out according to the test procedure in this standard and return the results to the Water Corporation SCADA Engineer for approval. In all cases the final calculated mast height and antenna configuration needs to be approved by the SCADA Engineer.

6.1 Test Equipment Depending on the location and its expected signal level, some or all of the following test equipment will need to be taken to site:

• Mobile phone with Telstra SIM;

• Phone App installed that can carryout approximate 4G/3G signal measurements. For example “Network Cell Info”, however there are many to choose from:

• Sierra Wireless Airlink RV50 Modem with Telstra SIM installed and configured for

connection to the Telstra network;

• Shark-fin or similar low-profile antenna (at required frequency as indicated during desktop design);

• Colinear antenna (at required frequency as indicated during desktop design);

• High gain directional antenna (at required frequency as indicated during desktop design);

• Pre-connected Coaxial cable of 5 metre, 10 metre and 15 metre lengths;

• Spare coaxial cable, connectors and joiners;

• Laptop with Ethernet cable for connection to the modem;

• Throughput test software such IPERF3 (if available at the Central SCADA site);

• Telescopic pole to a minimum of 6 metres;




• Car wheel support bracket for telescopic pole;

• U-bolts, guy ropes, tent pegs and other accessories;

• Antenna attachment brackets;

• Compass (phone application should be sufficient for testing purposes); and

• 12VDC Battery and leads to power the modem.

6.2 Testing at a Site with High Modelled Signal Levels If the desktop design work has shown that there are strong 4G signal levels expected, greater than -90dBm RSRP on average at 2 metres, then there should only be a need to test the signal level with the Sharkfin or low profile antenna mounted on top of the SCADA cabinet.

Place the antenna on top of the cabinet and ensure the antenna is earthed (if required). Connect the antenna to one port of the modem using the 5 metre coaxial cable.

Power up the modem and laptop. Log into the modem using the ACEmanager web interface. Go to the “Cellular” tab and check that the RSRP and RSRQ levels are within the required range for this site. Record this signal to file for a minimum of 15 minutes using the option in the “Events Reporting” page. If this page only allows you to record RSSI, set up an SNMP trap for RSRP and RSRQ and record to file. Load the data into a spreadsheet in order to sort and find the averages.

An average RSRP signal level of greater than -110dBm, and average RSRQ greater than -12dB, over the 15 minutes of measurement, meets the requirements detailed in this standard.

If there is a second best server available at this site, force the modem over to the second Telstra RBS site/sector, whether 4G or 3G, measure the RSRP and RSRQ levels (or RSSI in the case of 3G) and check they are within expectations. Record this signal level for 15 minutes and determine the averages.

6.3 Testing at a Site with Moderate Modelled Signal Levels If the desktop design work has shown that there are moderate 4G signal levels expected, between -110dBm and -90dBm RSRP on average at 2 metres, then several antenna configurations may need to be tested.

The first test should be with the Sharkfin or low profile antenna mounted on top of the SCADA cabinet.

Place the antenna on top of the cabinet and ensure the antenna is earthed (if required). Connect the antenna to one port of the modem using the 5 metre coaxial cable.


An average RSRP signal level of greater than -110dBm, and average RSRQ greater than -12dB, over the 15 minutes of measurement, meets the requirements detailed in this standard. If this is the case, then no further testing is required.




If the average RSRP signal level does not meet this standard’s requirements then a second antenna configuration needs to be tested. The same modem test shall be carried out using the co-linear antenna mounted on the telescopic pole, raised at 2 metre increments until the required RSRP levels are obtained or the maximum pole length is reached. Secure the co-linear antenna to the top of the telescopic mast, connect it to the modem using the 10+ metre pre-terminated coaxial cable and raise the mast up in 2metre increments.

Record the RSRP and RSRQ levels for a minimum of 15 minutes at each 2 metre increment. It should be that the acceptable height is the case when the average RSRP signal will be greater than -110dBm and the average RSRQ greater than -12dB.

If the received signal level is still below the required minimum signal level, then the link will need to be reverse engineered at the desktop using modelling software such as Mentum Planet. The technique to do this is discussed in the next section 6.4.

If there is a second best server available at this site, force the modem over to the second Telstra RBS site/sector, whether 4G or 3G, measure the RSRP and RSRQ levels (or RSSI in the case of 3G) and check they are within expectations. Record this signal level for a minimum of 15 minutes.

6.4 Testing at a Site with Low Modelled Signal Levels If the desktop design work has shown that there are low 4G signal levels expected, less than -110dBm RSRP on average at 2 metres, then several antenna configurations may need to be tested.

The first test should be with the co-linear antenna mounted on top of the 6+ metre telescopic mast. Secure the co-linear antenna to the top of the telescopic mast, connect it to the modem using the 10+ metre pre-terminated coaxial cable and then raise the mast to 6metres.

Connect the antenna to one port of the modem using the 10 metre coaxial cable.


An average RSRP signal level of greater than -110dBm, and average RSRQ greater than -12dB, over the 15 minutes of measurement, meets the requirements detailed in this standard. If this is the case, then no further testing is required.

If the average RSRP signal level does not meet this standard’s requirements then the telescopic mast should be raised to its maximum height beyond the 6metre height and the RSRP and RSRQ levels measured for 15 minutes.

If the average RSRP signal level does not meet this standard’s requirements then a second antenna configuration needs to be tested. The same modem test shall be carried out using the high gain directional antenna mounted on the telescopic pole at 6 metres. The telescopic pole shall be raised at 2 metre increments until the required RSRP levels are obtained or the maximum pole length is reached.




The direction of the Telstra RBS site from the SCADA site needs to be known in order to ensure the antenna is pointing in the correct direction. This information needs to be obtained from the modelling before coming to site. Use a compass to check for the approximate azimuth on site.

Check to see if the average RSRP signal is greater than -110dBm and the average RSRQ greater than -12dB when measured over a minimum of 15 minutes.

If the received signal level is still below the required minimum signal level when the telescopic pole is at its maximum height with the directional antenna on it, then the link will need to be reverse engineered at the desktop using the modelling software such as Mentum Planet. To do this:

• The average RSRP signal level measured in the field will need to be compared to that which is modelled in the software. This should be done using the same equipment configuration as used in the field (6+ metre mast, with same cable loss and direction antenna gain etc);

• The difference between the two levels in dBm needs to then be used in the software to calibrate (tune) the model to provide the correct RSRP reading in the software;

• Then using the calibrated (tuned) model the signal level can be more accurately modelled at different mast heights for that location’s environment; and

• Now model the link at every increasing mast heights until the required minimum average RSRP signal level is achieved.

If there is a second best server available at this site, force the modem over to the second Telstra RBS site/sector, whether 4G or 3G, and measure the RSRP and RSRQ levels (or RSSI in the case of 3G) and check they are within expectations. Record this signal level for a minimum of 15 minutes.

6.5 Connectivity and Throughput Testing Once an antenna configuration has been established using one of the three scenarios above, some basic connectivity and throughput testing shall be carried out before dismantling the test setup and leaving site.

6.5.1 Connectivity Testing Obtain the IP address of the Water Corporation central SCADA server or a connected core switch, and run a set of ping commands. It is recommended that the central site is pinged for at least 5 minutes with a variety of Ping commands. The following two ping commands are options:

• Ping -a -n 100 192.168.xxx.yyy

This command will ping the IP address 192.168.xxx.yyy, resolve the host name (-a), ping it 100 times (-n 100) with a 32 byte packet.

• Ping -t -a -I 1500 192.168.xxx.yyy

This command will ping the IP address 192.168.xxx.yyy, resolve the host name (-a), ping it continuously until commanded to stop (-t) with a 1500 byte packet (-I 1500).

Record the results of the ping tests to a text file or spreadsheet. The following command added to the end of the ping command will record the results in a text file called “PingyStuff”.




• Ping -a -n 100 192.168.xxx.yyy < C:\pingystuff.txt

6.5.2 Throughput Testing Throughput testing is also recommended as part of the suit of tests before dismantling the test setup.

To do this type of testing reliably and produce trustworthy results normally requires a client-server arrangement for the testing software. This means that a client agent will need to be installed on the Laptop and there will need to be server version of the test software at the Central SCADA site.

As an example, IPERF3 is a well-recognised freeware program used by many professionals for testing throughput across LAN and WAN links.

Results of any throughput testing carried out should be recorded to file for analysis back at the office.

7 Other Design Considerations

7.1 Fall-Back and Handover If the established link from SCADA modem to the selected 4G RBS site/sector fails, drops out or falls below a certain threshold for some reason, the modem will hunt for a new basestation.

Under normal circumstances, where the receive signal level is simply fading (more common when the UE is moving, such as in a car) the modem will “make before break”, that is, it will establish a new connection with a stronger RBS signal before disconnecting the current RBS. In this way no data or voice is lost or interrupted.

However, with the fixed subscriber installation that the Water Corporation is using, it is more likely that the connection with the same RBS will remain up unless it actually fails (assuming that the receive signal level is sufficient in the first place). In this case there will be no time for the modem to “make before break” and there may be a short (a few seconds) reconnection time.

The handover from one RBS to another is handled automatically by the modem and Telstra network core. No intervention is required by the user.

Note that the handover may be to another 4G sector on the same RBS or to completely new RBS. It may also be to a 3G site.

It is possible within the modem to list the order of preferred handover sites.

Where possible, a fall-back RBS sector should not to be at the same RBS as the best serving RBS sector. It is possible that if a fault develops with the best serving 4G sector, falling back to another 4G sector or 3G sector on the same RBS may not provide redundancy as a whole-of-site hardware or transmission failure may have occurred.

You can also force the modem onto a particular RBS site that has a weaker signal than the main site. The other stronger signal site being second in the order of preference. For example, you may wish to do this if the slightly weaker link is less obstructed by trees. When trees become wet the attention through them can increase dramatically. Or it may be that the weaker linked RBS has less traffic through it and so the throughput is higher on average.

It is recommended that when selecting the best serving cell/sector that the connection on the site remains stable and does not switch between different serving cells continuously. This is




particularly important for solar powered sites. Limiting the amount of signalling between modem and the RBS saves battery power as the radio modem is not continuously signalling for a better network connection.

Serving cell link stability can be observed by Airlink RV50 AceManager web page interface and taking note of the serving Cell ID. If the SCADA location is on the fringe area of two cells it may be beneficial to use a directional antenna at the expense of having an adjacent 4G LTE site for fall back. This decision would need to be considered carefully as it will reduce the reliability of the site as there may then not be a fall back option available.

7.2 Interfering Signals on the Uplink Path For a 4G technology provider such as Telstra it is important for the strength and quality of any one UE signal being received at the RBS to be comparable to all the other UE signals being received. Arbitrarily high signal levels from one or more UEs at the RBS that have unnecessarily high gain antennas or booster amplifiers is not desirable and can cause interference to the serving cell. In addition, high uplink signal levels at the base station are not required in 4G LTE technology as it does not suffer from cell shrinkage due to multiple users as is noticeable with 3G technology.

If a Carrier such as Telstra detects that there are one or more highly interfering signals which are creating a degraded service for all its customers using that RBS, the service provider will report the offending equipment to the ACMA. This will require the offending equipment to be switched off until the interference issues are rectified.

Therefore, high gain antennas should not be used if they are not required. Use the signal levels defined in section 5.2 and design guidelines discussed in section 5.4 to choose suitable antennas.

7.3 Modem Security As all network attached equipment has vulnerabilities, radio modems are also open to malicious access. Water Corporation document PM-9222304-v4 PTM discusses IP security over radio interfaces.

Below are some standard precautions that shall be implemented to the Sierra Wireless RV50 radio modem:

• Ensure that the RV50 radio modem has all available software updates installed to address any network vulnerabilities;

• Ensure all security rules, as defined by the Water Corporation SCADA Engineers, have been implemented on the modem including any or all of DMZ settings, IP/port filters, black lists, trusted IP lists, MAC filtering, port forwarding, access control, authentication, encryption etc

• Have a firewall installed and properly configured on the host device;

• Ensure that equipment cabinet provides sufficient physical security for the radio modem and peripheral devices;

• Use strong passwords or multi factor authentication for accessing sites and the master station;

• Keep the equipment and system passwords confidential and change them on a controlled and regular basis;




• Change the default administrative passwords of the radio modem before implementation;

• Secure unused/open Ethernet ports on the device;

• Have recovery plans in place if malicious damage to equipment or network attacks have occurred;

Enable logging and alerting of breaches in the IP network; and

Disable Wi-Fi access if the radio modem is configured with this option.

8 Typical 4G Antenna Types and Installation Examples for Fixed Subscribers The following section provides some examples of different types of antenna installations for 4G. There are many options, but any proposed installation design shall be approved by the Water Corporation Engineer before proceeding.

Refer to section 5 for design guidelines for choosing suitable antennas.

Antennas are available with SMA or N-type RF connectors. N-Type connectors should be used for longer RF feeder cable runs.

Antenna mounting brackets to suit the mounting structure should be ordered based on the diameter of the mounting pole.

8.1 Shark Fin and Low Profile Antennas The Shark Fin or Low Profile type antenna can be installed on top of the SCADA field cabinet. It can provide gains of approximately unity to 7dBd and cover all 3G and 4G frequency bands in the one antenna.

Shark Fin or other Low Profile antennas normally have a close-to-omnidirectional radiation pattern, although they will tend to have slightly elongated lobe. Being an omnidirectional antenna they should be able to service a fallback RBS site that is within range.

The Shark Fin antenna is generally a single dipole and therefore two antennas are required for a MIMO configuration. There are MIMO versions available but they will general have much lower gains (unity to 2dBd).




Figure 8-1: Typical Shark Fin Antenna – No MIMO

Figure 8-2: Typical Low Profile Antenna – With MIMO

8.2 Collinear Antennas The Collinear Antenna is a medium gain omnidirectional antenna.

Collinear antennas have the advantage that they are easily installed on top of a pole or similar high structure and provide good gain.

The Collinear can vary in size from 1 metre to 5 metres in length. Correspondingly the antenna will have gains that vary from 0dBd to 10dBd.




Antennas such as this are often narrowband and would therefore be designed to only operate in only one of the current allocated 4G bands. That is, either the 790-960MHz band or the 1710-2170MHz.

However, there are Collinear antennas available on the market that can service both bands, but generally they will have slightly lower gains (0dBd to 6dBd) than antennas that are designed to operate in only a narrow band. Often the gains across the two bands will be unequal depending on the designed configuration (for example the Telco Antennas “SKU: Omini 700 to 2700MHz” has a gain of 2.5dBd at 700MHz and 6dBd at 1800MHz).

The antennas can be designed to service multiply RBS sites, and fallback to a different RBS in case of failure is possible if there is an RBS within range.

Fall back from 4G to 3G will be possible with the multiband Collinear antennas. However, with the narrowband options there may be a small drop in gain as the antennas are generally tuned to one system or the other.

The Collinear is a single dipole only and therefore two antennas are required for a MIMO configuration. They would need to be installed in a vertical configuration, unless a horizontal bar is installed at the top of the pole. A horizontal configuration will provide a better MIMO outcome. Refer to Table 5-3 for appropriate antenna separations and confirm this in the manufacturers installation data sheet.




Figure 8-3: Typical Collinear Antenna Installation

8.3 High Gain Grid Pac Antennas The Grid Pac antenna is a high gain antenna for very low signal level areas.

It can vary in size from 1 metre to 3 metres in diameter. Correspondingly the antenna will have gains that vary from 15dBi to 30dBi.

Antennas such as this are generally narrowband and would therefore have to be designed to only operate in only one of the current allocated 4G bands. That is either the 790-960MHz band or the 1710-2170MHz, but not both.

The antennas could only be installed to service one RBS site, and fallback to a different RBS in case of failure would generally not be possible.

Fall back from 4G to 3G may be possible, but it would normally have to be off the same RBS site.




The Grid Pac is a single dipole only and therefore two antennas are required for a MIMO configuration. As can be seen in the photo below cross polarisation is achieved by using two grid pac antennas installed in a 45º and 135º cross pattern.

Figure 8-4: Typical Grid Pac Pole Mounted Installation

8.4 Long Periodic Antennas The Log Periodic antenna is a medium gain antenna, but has a very wide bandwidth of operation.

It can vary in size from 0.5 metre to 1.5 metres in length. Correspondingly the antenna will have gains that vary from 7dBi to 11dBi.

Log Period antennas can operate over a very wide range of frequencies, often from 700MHz up to 6GHz. Therefore, they can be used across the full range of 4G, 3G and WiFi bands and still provide reasonable directional gain.




The antennas would normally only be installed to service one RBS site, and fallback to a different RBS in case of failure would normally be difficult to achieve.

Fall back from 4G to 3G will definitely be possible, but it would normally have to be off the same RBS site.

The Log Periodic is a single dipole only and therefore two antennas are required for a MIMO configuration. As can be seen in the photo below cross polarisation is achieved by using two Log Periodic antennas installed in a 45º and 135º cross pattern.

Figure 8-5: Typical Directional Log Periodic Dipole Antenna Installation

8.5 Panel MIMO Antennas The Panel MIMO antenna is a medium gain antenna, but will operate over the full range of 3G and 4G frequencies.

The antenna will have gains that vary from 5dBi to 9dBi depending on frequency and designed configuration.

As the Panel antennas is highly directional it would normally only be installed to service one RBS site, and fallback to a different RBS in case of failure would normally be difficult to achieve.

Fall back from 4G to 3G will definitely be possible, but it would normally have to be off the same RBS site.




Figure 8-6: Directional Panel MIMO Antenna Installation

Design Standard DS42-05 4G Link Design and Measurement :

Uncontrolled if Printed - Ver 2 Rev 1 © Copyright Water Corporation 2019

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Appendix A VSCADA Site – Field 4G Modem Testing Record Worksheet

Date

Site Name

Site Address

Latitude

Longitude

Altitude

Clutter Around Site Photos work best - noting azimuth of each photo

SCADA Site Details



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RSRQ

(15 Min Ave)

Distance to RBS (km)

Ping Test Ave(ms)

Determine Best Serving Cell by adjusting Antenna Height.

If on a fringe area of two cells choose a directional antenna and conduct the measurements again (fringe area is within 6dB)

Through-put Test

Ave (Mbps)

Frequency Band

Record Locations and Measured Results from ACEManager Interface

Address of Telstra candidate sites Latitude Longitude Cell ID

RSRP

(15 Min Ave)

Azimuth to RBS

(degrees)

Test Antenna Height

AGL (m)

> -110dBmRSRP

RSRQ < -12db ( < -9dB optimal)

RSRP and RSRQ Guideline Levels. (15 Minute Average)



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Feeder Cable Type and Loss per Metre at 750MHz and 2100MHzFeeder Cable Length (m) and Total Loss (dB)

Antenna Gain

Test Equipment List

RV50 Radio Modem Serial Number

Final antenna height

Antenna Manufacturer and Part Number

Appendix B Additional 4G LTE Background Information The following appendix provides some additional background technical information on 4G LTE.

Appendix B.1 4G LTE Basic Parameters The following Table B-1 summarizes the basic parameters of 4G LTE radio systems:

Table B-1: LTE Parameters

Parameters Description

Frequency range UMTS FDD bands and TDD bands defined in 36.101(v860) Table 2, given below

Duplexing FDD, TDD, half-duplex FDD

Channel coding Turbo code

Channel Bandwidth (MHz)

1.4 3 5 10 15 20

Transmission Bandwidth Configuration NRB: (1 resource block = 180kHz in 1ms TTI )

6 15 25 50 75 100

Modulation Schemes UL: QPSK, 16QAM, 64QAM(optional)

DL: QPSK, 16QAM, 64QAM

Multiple Access Schemes

UL: SC-FDMA (Single Carrier Frequency Division Multiple Access) supports 50Mbps+ (20MHz spectrum)

DL: OFDM (Orthogonal Frequency Division Multiple Access) supports 100Mbps+ (20MHz spectrum)

Multi-Antenna Technology UL: Multi-user collaborative MIMO

DL: TxAA, spatial multiplexing, CDD ,max 4x4 array

Peak data rate in LTE

UL: 75Mbps(20MHz bandwidth)

DL: 150Mbps(UE Category 4, 2x2 MIMO, 20MHz bandwidth)

DL: 300Mbps(UE category 5, 4x4 MIMO, 20MHz bandwidth)

MIMO (Multiple Input Multiple Output)

UE: 1 x 2, 1 x 4

RBS: 2 x 2, 4 x 2, 4 x 4

Design Standard No. DS 42-05 SCADA 4G Link Design and Measurement



Parameters Description

Coverage 5 - 100km with slight degradation after 30km

QoS End to End QOS allowing prioritization of different classes of service

Latency End-user latency < 10mS




Appendix B.2 LTE – Communication Channels The information which flows between the different protocols is known as channels and signals. LTE uses several different types of logical, transport and physical channel, which are distinguished by the kind of information they carry and by the way in which the information is processed:

• Logical Channels: Define what type of information is transmitted over the air, e.g. traffic channels, control channels, system broadcast, etc. Data and signalling messages are carried on logical channels between the Radio Link Control (RLC) and Medium Access Control (MAC) protocols.

• Transport Channels: Define how something is transmitted over the air, e.g. what is encoding and interleaving options used to transmit data. Data and signalling messages are carried on transport channels between the MAC and the physical layer.

• Physical Channels: Define where something is transmitted over the air, e.g. first N symbols in the DL frame. Data and signalling messages are carried on physical channels between the different levels of the physical layer.




Appendix B.3 4G Operating Frequency and Band Numbers The following Table B 2 provides the 3GPP defined 4G LTE E-UTRA operating bands and their corresponding frequency bands

Table B-2: E-UTRA Bands and Corresponding Frequencies




END OF DOCUMENT

SCADA 4G Link Design and Measurements

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