Private long-term evolution (LTE) networks offer considerable benefits to support utility operations. For utilities that pursue this technology, one of the most difficult decisions will be identifying the optimal evolved packet core deployment solution.
The benefits of a private LTE network for a utility include data collection, workforce management support and cybersecurity enhancement. Utilities can leverage private LTE to garner data from various grid assets, such as smart meters, sensors and distributed energy resources. This data can enhance grid reliability, help staff make informed decisions and reduce operating costs. Also, cybersecurity is critical to support an automated grid. Private LTE networks offer enhanced security, so utilities can implement additional protective measures.
As utilities explore their private LTE options, they have opportunities to shape and enhance their network architecture. Utility owners and operators can choose from on-premise, off-premise or a hybrid approach. For a utility, this decision will impact financials, operations and maintenance, and cybersecurity.
Private LTE Architecture
To differentiate among the various options for evolved packet core deployment, it is helpful to first understand the layers that encompass a utility private LTE network. The first layer involves utility devices — including smart meters, EV charging stations and security cameras — that are connected to and monitor the utility’s assets. The second layer is the LTE connection layer, which has two main parts: radio access network (RAN) and the backhaul network. The RAN comprises devices like remote radios and baseband units positioned at utility tall assets to send signals across the utility service territory. The RAN network connects to the core network layer via the backhaul network, which employs multiprotocol label switching over fiber, microwave or satellite. The third layer is the core network layer, which includes the 4G/LTE evolved packet core or 5GC. This layer manages device location, authentication, and communication with internal tools and the internet. This layer hosts the operations, administration and management front-end interface to monitor and control the performance of the RAN and evolved packet core network. The final layer is the application layer. This is where utility devices connect to various applications, which can be created by the utility or come from a third-party application that runs in the cloud.
Understanding the private LTE architecture can help utility owners and operators identify the optimal evolved packet core deployment solution for their operations. Evolved packet core deployment solutions include on premise, utility managed, vendor managed or off premise.
In this situation, the utility acquires the requisite hardware and software to operate the evolved packet core. The hardware and software are housed in a data center, or multiple data centers, in a geo-redundant setup, which is recommended to provide the utility complete control over the entire network and mitigating security risks. The utility can opt to self-manage the network or collaborate with a third-party vendor.
When utilities manage the deployment of the evolved packet core, its critical to budget for training and extra staff time in the operational costs. While training the in-house workforce, owners and operators can consider a temporary arrangement with the vendor. In this scenario, the original equipment manufacturer (OEM) would manage the network for a defined period, tending to hardware, upgrades and patches to verify that the mobile network meets or exceeds the service level agreement performance metrics. Ultimately, the utility will take over long-term network maintenance.
Third Party or Vendor Managed
Instead of the utility owning and operating the hardware and software required to support the mobile core network, a vendor can provide a functioning core networking — including the hardware — that will reside on the utility’s premise. The vendor takes responsibility for hardware maintenance, upgrades and patches. Opting for a third-party or vendor-hosted solution simplifies the utility’s responsibilities, especially for network setup and required hardware. One downside of this approach is that it often translates into an operational expense for the utility.
There are several off-premise deployment options for utilities to consider. One option involves an OEM offering to host the evolved packet core off-site, thus handling all core operations remotely. However, this approach requires the utility to route all RAN backhaul to the original equipment manufacturer’s core, potentially raising security concerns as device data leave the utility network to connect with its intended application. Financially, this approach would result in an operational expense for the utility.
Utilities can also deploy an evolved packet core off premise using a cloud provider. The core software can be deployed in the cloud, and the utility can choose to manage the LTE core itself or contract with a third party. This approach often raises both financial and cybersecurity concerns.
A hybrid approach — both on premise and off premise — is available to utilities in which a utility’s user plane function remains on premise while other core functions go off premise. This can mitigate security concerns associated with sending data outside of the utility network.
One final off-premise approach involves two utilities collaborating, especially if one utility already has a private LTE network to host the evolved packet core. This approach is especially beneficial for smaller utilities that want private LTE but lack the financial resources. Using this approach, the new utility piggybacking off the other utility’s private LTE can build the RAN, while the backhaul is sent to the core hosted by the utility with an established network. The new utility can avoid the complexities of operating an LTE core while benefiting from a shared security and reliability strategy. Also, it is likely that the two utilities could negotiate reasonable financial terms.
When identifying the optimal evolved packet core deployment solution, utilities can choose from an on-premise, utility-managed, vendor-managed or off-premise approach. Understanding the layers of private LTE network architecture can help make informed decisions about evolved packet core deployment. Ultimately, the deployment strategy should align with the utility’s needs, available resources and long-term objectives, especially regarding cybersecurity.
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