White Paper Prepared by Justin Wyatt, Principal Consultant, October 2018  |  Download PDF Version

Why LTE? When properly designed and maintained, an LTE network offers better coverage, capacity and capability than previous industrial wireless networks. 

1. Introduction

The mining industry has been embracing innovative technologies as they strive to increase both production base and efficiency in tough economic markets. Many are turning to automation and remote operation technologies throughout their businesses such as, driverless trains and haul trucks, remotely operated plant, train loading and mine control. Others are turning to asset health technologies and condition monitoring over regular preventative maintenance to reduce costs.

As these technologies are rolled out, the last mile wireless network that supports them has become a critical component of mine infrastructure.

LTE offers a technology solution that is licensed, reliable, scalable and that can handle not only these automation and asset health applications, but also most of the existing legacy applications on a mining site such as push to talk voice, industrial control and telemetry. LTE vendors have evolved their product line-up to support enterprise scale solutions for the industrial and mining sectors.

This White Paper gives an overview of current LTE technology advancements and investigates what challenges are presented to the deployment of LTE in a mining setting.

2. Advantages of Enterprise LTE

In the carrier world, the advantages of LTE are well known, and it is the current technology of choice for the rollout of high capacity, low latency networks.

LTE is an evolving technology, with release 15 of the standard laying the foundation for the 5G networks of the future. For enterprise scale systems, used in the industrial or mining sector, the following advantages can be expected from an on-site enterprise scale LTE network:

1.  Low latency to support critical systems, voice and video.

2.  Spectral efficiency, giving high capacity even with 5 or 10 MHz channels.

3.  Designed for seamless mobility.

4. Licensed frequencies used, significantly reducing the risk of network interference or intrusion.

5.  The ability to converge multiple existing networks while maintaining traffic separation and QoS.

6.  Scales well from a single site up to hundreds of base stations

7.  Supports both low power and high power radios which can cover from small indoor areas to over 100km2 in good terrain.

8.  Has high reliability and availability to support your critical systems.

3. Components of LTE

LTE is broken down into a number of fundamental logical building blocks which provide the various functionalities required of the network. The following blocks are essential:

 

  • UE – The user equipment (modem) which provides mobile connectivity.
  • eUTRAN – The radio access component (base station) allowing UE access the network.
  • MME – The mobility agent that facilitates initial authorisation onto the network, sets up the default bearer for a UE and controls handover between base stations.
  • S-Gateway – The agent responsible for anchoring the end user devices mobility solution within the network.
  • P-Gateway – The agent responsible for providing the SGi (APN) interface from the LTE network to outside networks.
  • HSS – The database which holds the subscriber authentication information.

Extra functionality can be added to these blocks such as voice, dynamic QoS, multimedia broadcast, push to talk, billing, location services etc. While these are not required, they may be useful for replacing legacy systems or for providing new functionalities desired by industry.

4. Scale

The LTE components are considered logical or functional blocks, not physical blocks. Most vendors have multiple options for implementing these blocks and have evolved their product offerings to scale from small single chassis systems that may support 10 base stations and 1000 users to multi rack systems which support tens of thousands of base stations and millions of users. Some vendors have a separate range of equipment that is designed specifically for enterprise scale systems.

LTE offers some distinct RF advantages over other wireless technologies that have traditionally been implemented in a mining setting. Since the frequencies used are licensed, the hard work of coordinating frequencies and determining potential interferers is done up front and the maximum allowed EIRP (which is a major factor in determining range) is much greater than those allowed for class licensed technologies such as 802.11 (WiFi).

There is a wide variety of base station types available on the market for LTE ranging from 120W RF power macro systems down to 100 mW pico-cells. Most of these base stations allow for the freedom to choose between a single omni-directional antenna through to highly sectorised high gain antenna arrangements above ground and the option for distributed antennas or leaky feeder systems for use underground or inbuilding.

Choice of vendor and determining the correct scale of equipment both at the core and radio access network level is very important to the initial capital costs and the future capabilities of the network; this choice must be made with a good understanding of the applications to be supported and the number of network users, both initially and over time.

5. RF Planning

Mining has the unique challenge of continuously changing ground topology that is not present in almost all other networks. Having adequate GIS information and regular updates from the mine planners is vital to good RF planning for the network.  An understanding of propagation within the mine environment is also essential.

Due to the use of licensed frequency spectrum there is a requirement to apply for licenses to operate the network, which must be coordinated with the Australian Communications and Media Agency (ACMA) or the local RF regulatory body in the country of deployment. There may also be a requirement for base stations to be mobile, which adds an extra level of complexity to network planning and license approval. Often spectrum has not been allocated specifically for industry within bands that are desirable for use. Negotiation with the spectrum regulator and coordination of licenses is often the first and most difficult hurdle to be overcome in the RF planning process.

Unless the propagation characteristics are well known for the frequencies allocated and the ground types for the area to be covered, a very conservative approach should be taken for the initial sites link budget and model choice. The link budget and model should be verified and updated after the first site
RF survey is performed and this should form the baseline for ongoing RF planning.

The ability to provide temporary coverage for areas that are rapidly changing should be high on the list of considerations, options include:

  • RF Repeaters
  • Small Cells / Pico Cells
  • Local WiFi rebroadcast with InterRAT (Inter-Technology – Radio Access Technology)
  • Hybrid networks using standard WiFi with LTE

6. Capacity and Coverage

LTE provides superior coverage and throughput compared to most other mobile RF technologies currently used in a mining setting; however, throughput and coverage in an LTE network are related. If low throughput is required and there are relatively few clients, a single site may have a coverage radius of 15km or more (depending on allocated channel frequency, bandwidth and terrain
limitations).

If there is a large number of clients within a cell, or those clients require continuously high throughput (such as streaming video) then the cell size can shrink significantly – this effect is known as cell breathing.

This effect must be taken into account when designing the network as too much overlap will cause dominance issues leading to poor signal to noise ratios and conversely, too little overlap may cause coverage holes to appear and disappear within the network as traffic load changes.

The figure below shows relative coverage of a single base station ignoring the effects of interference for WiFi (shown in green), LTE small cell (shown in orange) and LTE macro (shown in red). The coverage has been simulated using typical base station and client device parameters such as RF power outputs and antenna gains and uses the 1.8 GHz band for LTE and 2.4GHz for WiFi. The same propagation model has been used for each system for simplicity of comparison. Each grey radial is 1km in distance.

Coverage comparison between WiFi, LTE Small Cell and LTE Macro Sites

Figure 1 – Coverage comparison between WiFi, LTE Small Cell and LTE Macro Sites.
WiFi (shown in green), LTE small cell (shown in orange) and LTE macro (shown in red).

7. Applications

Proper RF design is driven by both coverage and capacity, which means that the distribution of clients over the area to be covered and their traffic profile over time are both important factors for designing the network. Accurately mapping traffic requirements requires a deep knowledge of the applications that are to be deployed on the network, the number of clients using each application and their average density (and mobility) within the mine.

This information is often the most difficult to obtain and many assumptions may have to be made during the application discovery phase which may impact the final design. Some applications may also make use of multicast / broadcast traffic or other layer 2 protocols which cannot be transferred directly over
an LTE network and will require an overlay network to be designed to support these requirements.

An overlay solution adds additional complexity which must be considered such as reconnection and convergence times, vendor interoperability and choosing of UE / head end devices which support the correct protocols.

To minimise future outlay, the application discovery phase should take into account future application requirements where possible and how these may affect the scale of the network. Allowing for extra capacity at the outset and/or purchasing equipment which can scale to the required future state may allow initial outlay to remain reasonable while providing an upgrade path with minimal future cost.

8. Convergence, Security, QoS

LTE networks generally have the capacity and ability to provide a number of side-by-side virtual networks called APNs (similar to VLANs or VRFs). Each APN is a separated network which segregates traffic from other APNs and comes with a separate set of QoS parameters. Applications can be given different priorities both within an APN and priorities can be provisioned between APNs. User traffic and network control traffic can be optionally encrypted in an LTE network if this level of security is required.
Depending on capacity, coverage, security and business requirements, an enterprise LTE network may allow multiple networks on site to be combined and allow one or even multiple companies to leverage a single set of infrastructure for all of their applications rather than standing up multiple physical networks. This can be especially useful where miners have shared infrastructure such as ports or rail lines/facilities.

9. Conclusion

As industry and mining embrace new, advanced technology and wireless networks become a critical system to supporting the business value chain, the technology used for wireless connectivity must be put under the spotlight.

LTE’s carrier network roots give it the reliability, availability and security required to support industry needs, and vendors have responded to market demand by providing enterprise scale solutions which fit the business needs of the industrial and mining sectors.

Designing LTE networks is not as straightforward as previous generations of industrial wireless technology, yet LTE offers more advantages in coverage, capacity and capability over those previous networks. When properly designed and maintained, an LTE network can be very cost effective, supporting multiple applications simultaneously, with higher availability and more stability than previous generations of network. This translates into more uptime for your production applications and less adds, moves and changes on your wireless network, reducing total cost of ownership.
This white paper was originally released in September, 2013 and has been updated in 2018 to reflect current insights.

About the Author

Justin Wyatt is a solutions architect specialising in ICT networks and infrastructure solutions. He is a respected subject matter expert in systems engineering and telecommunications architecture and is equally comfortable in the design office or on site using his broad range of experience.

With deep domain understating of wireless, fibre optic and IP systems, including both enterprise and carrier technologies Justin has advised major corporations in setting a platform within their wireless and transport operational strategies.

Justin’s expertise lies in end-to-end engineering, from stakeholder engagement and requirements gathering through to design, installation, commissioning, customisation and integration into existing systems/applications.

An advocate for knowledge sharing, Justin happily imparts his learnings as a mentor to Titan ICT’s junior and graduate engineers.

About Titan ICT

Titan ICT is an Australian-owned company specialising in strategic ICT advice, systems integration and technical support services to deliver high quality integrated technology and business solutions. With a proud record of delivery since 2003, we have a national footprint with offices located Perth, Brisbane, Melbourne and Sydney.

From the outset the decision was made to focus purely on ICT disciplines providing trusted advice and engineered solutions that tackle technology transformation and maximise the potential of any project, big or small.

As a result, we are at the forefront of new technologies by constantly turning to innovation and ingenuity for the development of tailored, leading-edge solutions that support the operational and strategic objectives of the companies we work with.

By working with us, you too can enjoy the success that results from the bringing together of world-class skills, best in breed products and practical know-how in planning, managing and delivering complex scopes of work.

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The author only represents himself as competent professional in the planning, design and implementation of Telecommunications and Information Technology systems, networks and practice. Any statement provided which may be of a legal nature is only offered as an opinion based on the author’s understanding of the law and how it may apply. The author has made every effort to identify all relevant and available source data in the preparation of this document. All surveys, forecasts, projections and recommendations are made in good faith on the basis of information available at the time. The author, its agents, licensee and/or other representatives disclaims any liability for loss of damage caused by errors or omissions, whether such errors or omissions resulted from negligence, accident or other causes. Neither the author, its agents, licensee nor representatives will be liable for any loss or other consequences (whether or not due to the negligence of the author or their agents) arising out of the use of information in this report. No responsibility is taken for the accuracy of this information in relation to pricing or functionality of products and services described in this report. Readers should confirm with the appropriate service provider as to the validity of the information and any variations which may have taken place since publishing.