The Case for Incremental pLTE Coverage: Top Considerations for Utilities

Assessing the business case for your private LTE (pLTE) vision requires a deep understanding of mission-critical infrastructure that is operated by utilities and pLTE technology. Among the top reasons to shift from public cellular to pLTE include reliability, resiliency and financial benefits. 

While the overall drivers and benefits of pLTE adoption are inherent, a lingering question remains: Should utilities put all their chips on the table and invest in pLTE technology at once or take a more gradual approach? 

Here, we answer that question and share a more business-driven approach to pLTE adoption. 

How can Utilities deploy pLTE incrementally? 

Leading Utilities across the U.S., including Ameren, Southern Company, San Diego Gas & Electric and more, are deploying pLTE networks. While several Utilities are conducting pLTE assessments and trials, the pioneers have shared characteristics such as: 

• Assumed significant value and growth of connectivity use cases.
• Licensed spectrum.
• Plan to provide full coverage.

As they see an expansion of the quantity and value of use cases needing cost-effective, reliable and secure communications, they have invested in licensed spectrum as the foundation for a homogeneous pLTE network. These industry leaders have opted to fund programmatic coverage implementations (shown below). However, this model comes at a premium, requiring a nine-figure investment commitment from day one.

Unfortunately, not every utility can make that commitment. For example, your Advanced Metering Infrastructure (AMI) and Land Mobile Radio (LMR) refresh cycles may not align or you only have funding for smaller milestones. In that case, Utilities may prefer a business-driven implementation.

Key considerations as Utilities approach gradual pLTE adoption 

Several scenarios that demand a more gradual approach are worthy of consideration. Larger utilities may need pLTE coverage, but don't have on-hand capital. Organizations might forecast the need for adopting more grid control devices, but they are targeted for more focused areas within a grid. An organization may want to modernize a power plant with pLTE technology, but leverage components such as Evolved Packet Cores (EPCs) for future use in the distribution grid. These are just a few scenarios Utilities contend with. 

Historically, spectrum was only available for purchase across the entire service territory or not at all. EPCs were incapable of starting small and growing, and the endpoints, including the SIMs, were fixed to specific carriers. This meant pLTE required significant upfront costs with limited flexibility to adapt to different spectrum options or business needs in the long term. Hence, a service-territory-wide and homogenous deployment was required to justify the upfront costs. Some changes in these critical areas have made "starting small while planning big" with pLTE much more feasible today.

Spectrum

An initial decision for Utilities is selecting their radio spectrum, which can fall into several categories: licensed spectrum acquired from the Federal Communications Commission (FCC) or leased from existing owners; lightly-licensed, non-exclusive CBRS-GAA spectrum that requires an initial registration and a nominal monthly subscription fee; or public carrier spectrum acquired directly from the carrier or through a roaming partner.

If using a public Radio Access Network (RAN) through a carrier or roaming service provider, the factors to consider are: coverage, cost, ability to migrate to a private network, duration of the commitment to offer spectrum service and reliability. A roaming service provider might provide greater reliability and coverage at a lower cost with no commitment to the private network; however, most carriers also own spectrum that is set aside to sublet for private networks so they can provide a fully managed and private cellular option.

Roaming also affects ROI through system reliability, performance and security, drastically impacting user experience and device management. Moreover, roaming enables innovative advanced systems that would be difficult or impossible with a closed (non-interconnected) pLTE system. Utilities that allow roaming can fast-track their transition to pLTE even while seeking various approvals. All that is necessary is a core and an interconnection with a roaming partner.

With new, down-scaled cores, vendors are now offering budget impacts that are more accommodating, but not all roaming arrangements work in the same fashion as mentioned above. Endpoints might be from private or public LTE services that interwork with or are separated between the various cores. Interworked systems can peer with a favored carrier or an independent IP Exchange (IPX) with access to all service Utilities. Roaming might be driven by signal strength, reliability policies, security issues and even events. The choice of endpoints and SIMs play a key role in what roaming options might be open to service providers. If one did not initially anticipate roaming, there could be a hurdle to enabling some of these advanced and innovative roaming options.

When assessing spectrum options for a private network, factors for consideration include the cost and capacity of the spectrum, propagation characteristics, exclusivity/congestion, availability of approved endpoints and coverage. See the below chart as a reference point.  

The availability of spectrum, like its uses, will evolve over time, so architecting in a way that delivers short-term value while enabling long-term flexibility is critical to the Business-Driven Expansion model. Traffic analysis of initial use cases and an RF study for differing options can clarify relative costs and capabilities to help assess the right "starter spectrum." Integrators can help identify creative structures that work for each specific instance.

Evolved Packet Core (EPC)

EPC is a framework for providing data on an LTE network. Sizing for an EPC can be a complex design task. It usually begins with estimating the number of devices the system might eventually serve and the estimated quantity of traffic it will generate. If the initial system only needs to serve fixed devices, then some features, such as mobile voice, can be deferred. But features should not be dismissed as rearchitecting for mobility later can become costly. Thus, Utilities have traditionally had to weigh expensive and large EPCs from the start or face the risk of needing a complete rebuild in the long term.

Fortunately, EPC vendors are introducing innovative solutions that can start small and scale up. Choosing a "modular" EPC is also very strategic. Modular EPCs allow you to scale up gradually and allow scaling out by adding distributed EPC gateways around the operating territory. A small, scalable, modular EPC that can grow as your needs evolve is a great choice. 

Additional considerations for using EPC include on-premises versus in the cloud, required redundancy and geographic location. If you are interested in more context around these factors, please contact your WWT account team or click the Contact Us button at the bottom of this article. 

Radio Access Network 

RAN represents a sizable portion of any pLTE system as most electric utility pioneers are deploying macro-cell RAN infrastructure for ubiquitous coverage. However, intense design efforts go into planning and deploying RAN to maximize coverage while minimizing costs. If Utilities decide on using licensed coverage, it would be wise to invest in traffic analysis and complete coverage studies. Conversely, Utilities can omit RAN technology altogether and still have a fully functioning pLTE network by leveraging a private EPC with a roaming service provider. 

Next, organizations need to make decisions regarding the civil aspects of the RAN. Some spectrums benefit from higher installations, thus leaning towards tall towers. Alternatively, for CBRS, you can consider using monopoles, which often get zoning approvals more easily than towers. In WWT's experience, separating those aspects of the project is better than asking communications suppliers to bundle their construction. This leads to sales cost, insurance stacking and margin stacking with little value to Utilities. 

Lastly, organizations need to decide the scale of the RAN equipment for chosen sites. If one is attempting to "start small and plan big," they might want to acquire RAN equipment that is modular and allows them to add capacity (more throughput) or capability (more spectrums or radio channels) at a later date. 

UE endpoints

Another critical decision for Utilities is determining the viability of having their endpoints operating exclusively on their pLTE network or on a public LTE network. This decision will guide their end user, SIM, EPC and RAN strategy. It is essential to make this decision early to avoid CAPEX and OPEX issues later, as this can drastically impact return on investment. 

Other considerations

Owning versus X-as-a-Service (XaaS) solution elements

As the pLTE market evolves, more "As-a-Service" models have emerged to support various technology elements. Some offerings include:

• Mobile Virtual Network Operator (MVNO).
• EPC-as-a-Service (EPCaaS).
• RAN-as-a-Service.
• MOCN.
• Neutral Host RAN.

These represent a quickly evolving field of options to consider, and each has several factors to weigh. For further details, please contact your WWT account team or click the Contact Us button at the bottom of this article. 

Conclusion

There are several approaches Utilities need to consider throughout their pLTE journey. Some may have all the pieces, like funding and executive championship that warrant an "all in" approach. However, several Utilities require a gradual approach.  WWT's blend between Consulting and Infrastructure services, Advanced Technology Center Lab, Supply Chain and Integration services and more can help your organization define the right communcations strategy to enable grid modernization and improve grid safety, reliability, affordability, security and profitability.