Co-Authored by Rick Schmidt & Kathy Nelson
In the rapidly evolving landscape of cellular technology, a new standard is emerging that promises to revolutionize the reliability and flexibility of IoT device connectivity for utilities, particularly in field area network (FAN) backhaul systems. The Multi-Carrier eSIM, defined by the SGP.32 standard, represents a significant leap forward in addressing the longstanding challenges of network redundancy and automated failover in remote locations.
This innovation dramatically improves reliability and resiliency by allowing devices such as to switch seamlessly between multiple commercial cellular networks. While utility-owned private networks remain the gold standard for security and control, the multi-carrier eSIM provides a more secure and resilient solution that cleverly leverages existing commercial infrastructure. As we delve into the details of this groundbreaking technology, we will explore how it is set to transform the way utilities manage their smart grids and how it could potentially reshape the broader IoT ecosystem. The implications of this development extend far beyond just improved connectivity – they herald a new era of resilience, adaptability, and security in our increasingly connected world, all while optimizing the use of commercial cellular networks.
The International Global System for Mobile Communications (GSMA) is an organization with over seven hundred members that has been focusing on mobile technology standards 4G, 5G, and beyond for nearly 30 years. For several years, GSMA and their members have been working toward standards to move away from physical SIMs and the introduction of the capability to offer carrier diversity by device allowing cell carrier redundancy and automated fail-over capability.
While some companies have been able to offer software-based SIMs allowing multi-carrier flexibility to exist in the same remote device, and some modem manufacturers offer dual physical SIMs, this has been possible with proprietary hardware/software.
The ratification of the SGP.32 standard for IoT devices in May 2023 marks a significant milestone, introducing an international standard across cell carriers, SIM providers, and modem manufacturers. Several vendors are now building products to offer eSIM/eUICC capabilities with product releases planned for mid-2025. This development promises to revolutionize connectivity solutions for various industries, particularly in the utility FAN backhaul applications with promises to revolutionize non-mobile fixed location connectivity.
This article defines the technology behind the Multi-Carrier SIM and explores the overall value proposition for the eSIM for utility FAN backhaul, highlighting its potential to enhance reliability, flexibility, and efficiency in smart grid operations.
What does this mean for utility backhaul?
The implementation of eSIM technology can significantly enhance the reliability and flexibility of utility FANs. Various devices within the FAN can benefit from this technology, including:
- Advanced metering infrastructure (AMI) collectors
- Distribution automation devices in the feeders
- Video security cameras at substations
- Growth of cellular in the meter
- Communication solutions for emerging DER backhaul
- Other critical devices located throughout the utility FAN
These devices can be equipped with LTE modems featuring software-based SIMs. This technology offers a game-changing capability: the ability to switch between multiple cellular carriers (such as AT&T, T-Mobile, Verizon, and, in some cases, FirstNet - a dedicated network for first responders or switch to a Private LTE profile if that is also loaded into the eSIM) based on predefined business rules that can now include cellular connectivity performance.
For example, if the primary designated carrier's signal is lost, the device can automatically switch to a secondary carrier. Some systems even allow for third or fourth backup options if the device is provisioned with multiple cellular carriers. This redundancy ensures consistent connectivity, which is crucial for the reliable operation of utility networks.
The diagram below illustrates the structure of a Field Area Network in relation to the utility backbone, highlighting common use cases within the utility FAN. This visual representation helps to contextualize where and how eSIM technology can be applied to improve network resilience and efficiency.
What Challenges does eSIM Address for Utility Backhaul and Grid Modernization?
Communications Backhaul Resiliency: Many utility applications such as AMI and distribution automation are considered mission-critical, or operationally mission-critical, programs. The current use of cellular typically relies on a single physical carrier SIM, which is a single point of failure and presents two main challenges:
- If the carrier's signal strength is weak at a specific location, long-term backhaul communications could be problematic.
- If the carrier experiences an outage or service degradation, the device may enter a communication failure mode.
The Multi-Carrier SIM solution addresses these issues:
- If the primary carrier fails, the eSIM can fail-over to a secondary carrier profile.
- A third carrier can be set up as an additional backup.
- The statistical probability of multiple carriers failing simultaneously at the same location is significantly lower than with a single carrier.
Common Network Management Software: The introduction of the eSIM SGP.32 standard brings significant operational improvements. Vendors are developing headend software that can communicate with remote modems and eSIMs, allowing a single network management software platform to manage multiple carriers and various utility FANs. This network management software offers a comprehensive suite of features, including provisioning new locations, tracking end-device performance, monitoring cellular consumption, and making over-the-air changes to carrier profiles. Also, having a single software application helps reduce the touch points that the security team needs to monitor. Historically, utilities have faced challenges due to the diverse array of communication products deployed over 10–20-year lifecycles, including various licensed and unlicensed point-to-multipoint products, cellular modem vendors, and carrier-specific network management software. Managing these diverse end-devices required specialized knowledge of multiple radio network software packages. The Multi-Carrier eSIM, coupled with a single software solution from a specialized vendor, can significantly reduce the network management challenges, thereby streamlining operations and improving overall efficiency.
Competitive Cost/Capitalization of Costs: The landscape of cellular consumption costs is evolving favorably for utilities. As the cost per gigabyte (GB) declines, which is positive, other new types of costs are introduced with this business model such as for the sophisticated software that manages the SIMs, integration costs between the eSIM, modem and head end software. New pricing models are surfacing to allow a “bundle” of all costs with an upfront prepayment cost model.
Possible Longer Service Life: The advent of LTE and 5G modems and eSIMs brings with it a significant shift towards software-centric operations. This transition involves a greater reliance on software and enhanced capabilities for over-the-air (OTA) device firmware upgrades. As a result, these newer technologies offer greater possibilities for extended service life and improved scalability compared to their predecessors (2.5G, 3G, or 4G).
What utility applications can the new eSIM address effectively?
The adoption of eSIM technology in the utility sector is expanding, with various vendors offering solutions tailored to different device types and applications. These solutions generally fall into two categories:
- IoT-focused eSIM solutions: Some vendors, such as Semtech.com (formerly Sierra Wireless), offer eSIM solutions specifically designed for IoT devices with integrated modems. These are typically used in fixed or semi-fixed utility assets.
- Broad-spectrum eSIM solutions: Other vendors provide eSIM capabilities that can communicate with both IoT devices and mobile devices (iOS and Android), enabling applications like mobile workforce management.
The versatility of eSIM technology makes it suitable for a wide range of utility Field Area Network (FAN) applications. Some of the most common areas where eSIM can be effectively deployed include:
- Advanced Metering Infrastructure (AMI)
- Distribution Energy Resource Management (DERMS) residential and C&I
- Distribution Automation
- Substation Automation
- Mobile Workforce Management
- Video Surveillance and Security
- Demand Response Systems and DER backhaul such as solar farm monitoring
In the following sections, we will explore each of these applications in detail, discussing how eSIM technology can enhance their functionality, reliability, and cost-effectiveness.
AMI Backhaul: Regardless of the AMI vendor—mesh-based (e.g., Itron, Landis + Gyr, Honeywell, Eaton, Tantalus) or licensed point-to-multipoint (e.g., Sensus, Aclara)—metering data is collected at network gateway locations.
Investor-Owned Utilities (IOUs) may have 1,000+ collectors/gateways across their territory, each handling 1,000-2,000 meters. While distribution cooperatives and municipal utilities typically have fewer collectors, their operational needs are similar but can differ due to a geological cellular coverage in rural areas where one carrier may be more prevalent than another.
Most utilities record metering data at 15-minute intervals, routing it to AMI collectors every 15, 60, or 240 minutes via private AMI systems. Each meter generates 700-1,200 bytes of data per 15-minute interval, depending on the AMI vendor. Consequently, cellular data consumption correlates with the number of deployed meters and the recording frequency.
AMI backhaul has moderate latency requirements since the data isn't time-sensitive for human use. Instead, interval data is typically sent to the meter data management system. A cellular modem in the collector with 500 Kbps throughput can adequately meet AMI backhaul bandwidth needs.
Cellular is an effective and commonly used backhaul medium. The AMI use case can be further strengthened by implementing carrier diversity and effective network management software with an eSIM SGP.32 standard, offering advantages over traditional single-carrier cellular solutions.
Distribution Automation Backhaul: Many electric utilities have implemented distribution automation (DA) programs and continue to expand them. DA often is considered a mission-critical application, with utilities expressing concerns about cellular reliability, particularly during major storms when high reliability is crucial.
Typical DA programs transmit approximately 300 bytes of data per device every 5 to 60 seconds. The ability to have seamless carrier diversity and effective network management software is extremely valuable for these near mission-critical DA programs. This is particularly important because in some locations, one carrier may have a coverage gap while another major carrier offers excellent coverage.
However, it's worth noting that certain DA use cases require very low latency, around 3 milliseconds, for which cellular technology is not optimal. In these specific scenarios, alternative communication methods, such as utility-controlled private wireless broadband networks, may be more suitable.
The implementation of multi-carrier solutions and advanced network management can significantly enhance the reliability and effectiveness of DA backhaul systems, addressing many of the concerns utilities have about using cellular networks for these critical operations.
DER Devices Behind the Meter: The use case for communicating with behind-the-meter distributed energy resources (DER) is gaining interest, particularly for programs like virtual power plants (VPP). This emerging field presents challenges due to the proprietary protocols used by various inverter and EV charger manufacturers, as well as high bandwidth requirements.
Some VPP scenarios demand near-streaming data, with approximately 1 MB files being transmitted every minute to the distributed energy resource management system (DERMS) headend. Cellular networks can meet these requirements, and having carrier diversity is particularly beneficial in ensuring reliable communication.
DER use cases involve various communication patterns:
- Some require the headend to push data down to the end devices
- Others involve end devices pushing data upstream
- Many scenarios necessitate bidirectional data flow between end devices and the DERMS master
Cellular technology, especially with multi-carrier solutions, can effectively support these diverse communication needs. This flexibility makes it a viable option for managing the complex data exchange required in DER systems.
Multi-Carrier eSIM in the Meter: Although the AMI vendor community has not yet widely adopted eSIMs with multi-carrier profiles and over-the-air configuration, this approach shows significant promise. Utilities should closely monitor industry developments in this direction.
The SGP.32 standard addresses lower-power NB-IoT and LTE-M devices capable of operating on battery power. This is particularly relevant for water and gas AMI and asset management programs, where such devices are becoming increasingly common.
Other Utility FAN Use Cases: Multi-Carrier eSIM technology is well-suited for various utility applications beyond metering, including:
- Video security cameras
- Substation SCADA systems
- Gas and water SCADA systems
- Street light controls
- RTUs for large renewable energy sites
These applications can benefit from the flexibility and reliability offered by multi-carrier eSIM solutions, potentially improving connectivity and operational efficiency across diverse utility infrastructure and various levels of carrier connectivity.
As the utility sector continues to evolve, the adoption of multi-carrier eSIM technology could play a crucial role in enhancing communication capabilities and network resilience for a wide range of utility applications.
FAN Use Case Communication Requirements
A sampling of communication requirements is listed below.
Communications Media Alternatives for the FAN
The following are effective communications media for the Field Area Network:
The adoption of Multi-Carrier SIM technology, utilizing the standard SGP.32 protocol, addresses several key challenges and limitations in existing FAN backhaul communications. This approach offers significant improvements in various areas:
- Enhanced Reliability: Mitigates concerns associated with single-carrier cellular dependence by providing access to multiple networks.
- Improved Bandwidth: Offers sufficient data throughput, surpassing the capabilities of traditional narrowband technologies.
- Versatility: Supports low-power NB-IoT options, making it suitable for battery-powered applications and devices.
- Cost-Effectiveness: Provides competitive pricing and greater flexibility in capital expenditure planning.
- Robust Ecosystem: Benefits from a thriving and maturing vendor community, primarily comprised of virtual network operators (VNOs).
This multi-carrier approach represents a significant step forward in utility communications, offering a more flexible, reliable, and capable solution for diverse FAN backhaul needs. It effectively bridges gaps in existing technologies while providing utilities with a future-proof communication infrastructure.
When it comes to utility FAN communications, it is crucial to understand that no single technology is universally best. The optimal choice varies depending on the utility's specific circumstances. For many larger investor-owned utilities (IOUs) with high-density electric, gas, or water assets, private LTE (PLTE) may be by far the most attractive FAN communications medium. In contrast, for many cooperatives with extensive rural areas, licensed wideband or narrowband point-to-multipoint technology might be more suitable due to numerous cellular coverage gaps. However, a larger utility with a mix of rural, suburban, and urban areas, planning to deploy over 5,000 devices, should consider a Multi-Carrier SIM solution. Smaller cooperatives and municipal utilities could benefit from collaborating with their generation and transmission provider or statewide municipal associations to achieve the necessary economies of scale, as use cases across neighboring utilities are often similar. Even for utilities that have PLTE, the multi-carrier SIM solution can complement the build-out timeline and also fill PLTE build-out gaps in less dense areas.
Creating a turnkey multi-carrier solution from a single provider requires partnering with various best-in-class vendors. The new SGP.32 protocol has opened the capability for organizations to create eSIMs and eUICCs with multiple carrier profiles loaded into the eSIM. This standard allows for switching between profiles using over-the-air commands or logic derived from the modem, such as loss of signal. SIM manufacturers play a crucial role in this ecosystem, providing headend software to communicate with the eSIMs. The term "SIM applet" is becoming more commonly used to define the software interface between the device and modem in eSIMs. This evolving ecosystem offers utilities greater flexibility and reliability in their communication infrastructure, allowing them to tailor solutions to their specific communication needs and geographical constraints.
eSIM Multi-Carrier Solution Infrastructure Components
The U.S. cellular landscape is dominated by a few major players, commonly known as mobile network operators (MNOs). These include AT&T, Verizon, T-Mobile, and US Cellular. Each of these companies owns and manages its cellular infrastructure, providing nationwide coverage through their networks.
In addition to these established operators, Dish Network is in the process of building a nationwide 5G network. To ensure comprehensive coverage during this expansion, Dish has secured roaming agreements with both AT&T and T-Mobile, allowing their customers to access these networks where Dish's infrastructure is not yet available.
Another significant player in the cellular market is FirstNet, a network dedicated to first responders and public safety. Traditionally, FirstNet services have been offered through AT&T, leveraging their extensive network infrastructure.
The term "MNO” specifically refers to these major cellular carriers who own, operate, and maintain their own network infrastructure. This distinction is important in the broader context of the cellular service industry, as it sets these companies apart from other types of service providers who may rely on MNO networks to offer their services.
MVNOs are wireless communication service providers that operate without owning their own network infrastructure. Instead, they forge business agreements with MNOs to secure wholesale access to network services. This arrangement allows MVNOs to offer cellular services to customers while setting their own retail prices independently.
The MVNO business model enables these companies to provide wireless services without the substantial capital investment required to build and maintain physical network infrastructure. By leveraging existing networks, MVNOs can often offer more flexible or specialized services than traditional MNOs.
Some notable companies operating under this MVNO model include:
KORE Wireless: http://korewireless.com
NWN Carousel: https://NWNCAROUSELcom
Semtech (Sierra Wireless): http://Semtech.com
Vodafone: http://vodafone.com
Worldwide Technology: http://WWT.com
Syniverse: http://syniverse.com
Itron: http://itron.com
These MVNOs play a significant role in the wireless market by often providing niche services, competitive pricing, or catering to specific customer segments that might be underserved by larger MNOs.
Multi-Carrier eUICC Architecture as Defined by Kigen
To better understand the components of a multi-carrier profile system, it is helpful to examine the architecture as described by a prominent industry player. Kigen, a globally recognized SIM provider, has offered a comprehensive illustration of the multi-carrier components.
This architectural breakdown provides insight into the various elements that make up a multi-carrier eUICC (embedded universal integrated circuit card) system. In short, eUICC is the software component that allows the eSIM to be remotely provisioned. Kigen's perspective is particularly valuable given their extensive experience and leadership in the global SIM market. The carrier profiles can be provided at the factory with the modem or via OTA downloads.
The Multi-Profile eUICC
Source: Provided by Kigen with permission
eSIM Multi-Carrier Product Availability and Timeline
MVNOs have successfully offered multi-carrier solutions for many years, using dual physical SIMs or proprietary software. Many of these providers are well-established, multi-billion-dollar corporations with over two decades of global operations. Some have provided cellular services for AMI vendors or facilitated roaming arrangements for cellular carriers through private labels.
With the SGP.32 standard finalized in May 2023, vendors have been developing products incorporating this new standard, with availability expected by mid-2025. While these vendors may lack the brand recognition of companies like Cisco, Itron, Landis + Gyr (L+G), Eaton, or Honeywell in the utility sector, they are capable of providing mission-critical communications. They are creating multi-carrier solutions by partnering with major cellular carriers, SIM manufacturers, and software partners to deliver comprehensive solutions. Some large utilities are now entering the testing phase with pre-releases of the SGP.32 standard.
Complexity of Multi-Carrier Solution Implementation
It's important to note that the multi-carrier solution is not a simple "plug and play" system. Significant configuration is required to integrate the modem, billing/accounting, SIM applet, carrier profiles, and the application. This necessitates a development phase for each use case. As market share expands and we see consistency in applications interfacing with common vendors like Itron, L+G, OSI, Survalent, GE, or DERMS vendors, there is potential for API development between frequently deployed systems.
Value Proposition of the Multi-Carrier SGP.32 Solution
While cost is always a consideration in major infrastructure investments, grid modernization demands resiliency and high reliability. This has often led to the selection of private and licensed communication technologies. However, the multi-carrier solution is becoming increasingly attractive due to several factors:
- Security offered through LTE standards
- Architecture of MVNO providers
- Expected reliability of multi-carrier solutions
- Growing vendor community
- Competitive costs
It's worth noting that this protocol, business model and vendor turn-key solutions are breaking new ground. While promising, some caution is advisable, making it ripe for early adopters to explore and validate in real-world utility environments.
Acronyms defined and used within this article:
eSIM = Embedded Subscriber Identity Module - A programmable SIM chip embedded directly into a device which can be reprogrammed remotely.
eUICC = Is the software component that allows the eSIM to be remotely provisioned.
Applet or SIM Applet = A software application that runs on the SIM card (or eSIM). It handles communication between the modem and SIM and can be customized for specific use cases.
RSP = Remote SIM Provisioning
MNO = Mobile Network Operator – such as AT&T and Verizon
MVNO = Mobile Virtual Network Operator – non-infrastructure cell providers that resell cellular service and bundle various value-added software and networking support services.
About the Authors:
Rick Schmidt, long-time consultant in the electric utility sector that combines utility telecom and automation programs such as AMI, DA, MDM, Demand Response, new BTM meter programs and other digital technologies. Rick is now leading the digital deployment efforts of the City of Longmont Colorado Power and Communications. Rick Schmidt’s Contact Information: 608-358-5661 or [email protected]
Kathy Nelson, PE, is the Founder and Principal of KN Utility Telecom Consulting and a member of the UTECH Consultant Hub. With over 31 years in utility telecommunications, Kathy's experience spans leadership roles at Great River Energy, UTC, Ondas Networks, and West Monroe Partners. She's a former UTC Chairwoman and an advocate for women in STEM, hosting the podcast "Ordinarily Extraordinary-conversations with women in STEM."
Kathy is part of UTECH, which unites elite independent experts and specialized consulting firms in utility telecommunications and technology. UTECH delivers comprehensive capabilities with the agility of boutique providers.
Based in Minnesota, Kathy is a mother of three and owner of a lively sheepadoodle.