A stronger signal for a steadier grid

How South Louisiana Electric Membership Corporation (SLEMCO) traded aging radio towers for a cellular network that holds through lightning, fog, and heatwaves

South Louisiana Electric Membership Corporation (SLEMCO) is a U.S. public utility that purchases electricity from a generating partner in Florida and distributes it to customers across the region. The substations scattered across that territory are the backbone of the whole operation. When they go quiet, so does everything else.

For years, substation communications ran on a combination of 900 MHz radios and legacy point-to-point radio links arranged in a hub-and-spoke topology, with clusters of sites reporting to a central master device that relayed data back to headquarters. The architecture had a flaw baked into it: one failed master, and every substation connected to it went dark, regardless of whether those individual sites had any problems of their own. Ten locations could lose communication because of a single device.

Louisiana’s climate compounded those vulnerabilities. Lightning strikes took equipment offline. Dense fog swallowed signals. On certain perfectly clear days, sunlight intense enough to disrupt the radio links would quietly knock out communications across entire regions. Restoring service meant scheduling tower climbers for equipment mounted 50 to 100 feet up, billed by the foot, with after-hours premiums on top. Outages could stretch four hours or more. In the meantime, the team had limited alerts, little visibility into where outages were happening, and a harder time getting crews where they needed to be.

All that fell to a five-person IT team covering networking, cybersecurity, help desk, and everything in between. The infrastructure wasn’t just operationally fragile, it was a constant drain on a team that had no bandwidth to absorb it.

A network where every substation stands on its own

Working with Ericsson Enterprise Wireless Solutions and managed mobility services (MMS) provider Stratix, SLEMCO replaced its hub-and-spoke radio setup with a cellular network where each substation operates independently.

Stratix provided upfront consultation to identify the right combination of Ericsson Cradlepoint routers and Parsec antennas for the use case—ensuring optimal performance before full deployment.

Stratix coordinated AT&T FirstNet connectivity, including SIM provisioning, activation, and static IP configuration. Each device was asset-tagged with its assigned mobile number, simplifying identification, support, and troubleshooting in the field.

Now, a router at each SLEMCO site connects to the local controller, collects SCADA (supervisory control and data acquisition) data from equipment across the station, and routes it securely back to headquarters. At the data center, a dedicated router connects directly to the firewall protecting SLEMCO’s operational technology (OT) network through a hardwired port, keeping sensitive traffic isolated from the broader IT environment at all times. Because cellular connectivity does not require line-of-sight between sites, antennas mount directly at the substation rather than high on a tower, bringing installation heights down from as high as 100 feet to 25 feet or less.

All sites are managed through Ericsson’s cloud-delivered SD-WAN service, with every device monitored centrally through Ericsson’s NetCloud platform. Coverage runs on AT&T FirstNet; the priority network built for utilities and first responders. Strict network segregation and firewall rules ensure that only authorized sites can access the SCADA network, meeting compliance requirements without any compromise to the operational design.

Connecting across state lines, securely

SLEMCO’s network doesn’t just provide connectivity for its own substations. The cooperative works with a power generation partner based in Florida, and that relationship requires secure, reliable data exchange across hundreds of miles without creating an opening into SLEMCO’s infrastructure.

Ericsson’s Cradlepoint routers and enterprise networking capabilities made that possible. Using IPSec VPN tunnels, VTI tunnels, NAT rules, and routing policies configured within the platform, SLEMCO established a dedicated, controlled channel for its Florida partner to communicate with systems in Louisiana. The partner gets the access it needs, and SLEMCO retains full control of what crosses its perimeter, with documentation demonstrating that the connection meets the security requirements governing utility infrastructure.

What used to require a truck now takes 30 seconds

All of the approximately 130 deployed devices are centrally managed through Ericsson NetCloud, providing the team with real-time visibility, remote configuration, and instant alerts from a single platform. When a site drops off, the team knows immediately and can pull up the NetCloud mobile app to determine within seconds whether it’s a cellular issue, a VPN problem, or something at the station itself. That triage used to mean phone calls, guesswork, and sometimes a truck rolling out on a hunch. The after-hours on-call rotation that once revolved around lost sites and uncertain causes now looks very different.

With substation communications proven and stable, attention is turning to the field vehicle fleet, where crews currently rely on tablet hotspots for connectivity while staking, mapping, and completing job documentation in the field. The plan is to potentially add in-vehicle cellular routers that consolidate connectivity for an incoming radio system, GPS, and crew Wi-Fi into a single managed device, extending the same visibility already built into the grid to the people who maintain it.