When people think about private cell migration, they think about the core network and the radios. But for operations teams, the device side is where the migration is felt most acutely. Every scanner, tablet, camera, router, and IoT sensor that connects to your private LTE/5G network has a SIM card, an APN configuration, and — often — device-specific network settings that must be updated.
At scale, this is a logistics challenge as much as a technical one. Here's how we approach it.
The Device Inventory
Before touching a single SIM, we build a complete device inventory. This includes:
- Device type and model: Barcode scanners, rugged tablets, fixed cameras, mobile routers, CPE gateways, IoT sensors, AGV controllers
- SIM type: Physical SIM (2FF, 3FF, 4FF), embedded SIM (MFF2), or eSIM-capable
- Current IMSI and ICCID: The subscriber identity and SIM card identifier on the legacy network
- APN and network settings: Current APN, authentication type, static IP assignments, VLAN tags
- Band support: Whether the device supports the target band (e.g., CBRS Band 48) — this is a hard requirement, not a configuration change
- Firmware version: Outdated firmware can cause compatibility issues with the new core
This inventory drives everything: which devices can be reprovisioned in place, which need SIM swaps, and which need to be replaced entirely.
SIM Migration Strategies
There are three approaches to SIM migration, and most deployments use a combination:
Option 1: SIM Reprovisioning (Over-the-Air)
If your legacy vendor provides IMSI/Ki export and your devices support remote SIM management, we can reprovision existing SIM profiles to authenticate against the BATS ECHO core without physically touching the SIM.
- Best for: eSIM-capable devices, large fleets where physical access is difficult
- Limitation: Requires the legacy vendor to release IMSI/Ki data — some won't
Option 2: Physical SIM Swap
We issue new SIM cards pre-provisioned for the BATS ECHO core. Each device gets a new SIM, and the old one is decommissioned. This is the most common approach for traditional SIM deployments.
- Best for: Devices with removable SIMs, environments where physical access is routine (shift changes, docking stations)
- Logistics: We pre-label SIMs by device, provide swap instructions, and can deploy technicians on-site for high-volume swaps
Option 3: eSIM Push
For eSIM-capable devices, we push a new profile to the device remotely. The device downloads the ECHO profile, activates it, and the old profile is disabled — no physical contact required.
- Best for: Modern smartphones, tablets, and IoT modules with eSIM support
- Advantage: Can be done in bulk, on a schedule, with no operational disruption
Device Reconfiguration
Beyond the SIM, many devices need configuration changes:
- APN settings: The Access Point Name must match the ECHO core's configuration. On managed devices, this can be pushed via MDM (Mobile Device Management). On unmanaged devices, it's a manual or scripted update.
- Static IP reassignment: If devices have static IPs on the legacy network, these must be mapped to the new core's IP plan. We preserve existing assignments wherever possible to avoid breaking application integrations.
- Band lock / carrier lock: Some devices are locked to specific bands or PLMNs. These locks must be updated or removed for the device to connect to ECHO.
- Firmware updates: We align firmware across the fleet to the latest stable version compatible with ECHO. This prevents the support headaches of running mixed firmware in production.
Validation at Scale
Every device must be validated after migration. For a fleet of 500+ devices, this can't be done manually one at a time. Our validation process:
- Automated attach testing: We monitor the ECHO core's subscriber log to confirm each IMSI successfully attaches, authenticates, and receives an IP address.
- Throughput spot checks: A sample of devices across each type and location are tested for uplink/downlink throughput and latency.
- Application-level validation: For critical devices (scanners on a WMS, cameras on a VMS), we verify that the end application works — not just that the device has an IP.
- Exception tracking: Devices that fail to attach or show degraded performance are flagged, diagnosed, and remediated individually.
Our target is 100% device validation. We don't close a migration until every device on the inventory list is confirmed working on ECHO.
Phased Rollout
For large deployments, we don't migrate all devices at once. A typical phased approach:
- Phase 1 — Pilot (5–10%): A representative sample of each device type, in each location. Validates that the SIM strategy, APN settings, and core configuration work across the fleet.
- Phase 2 — Batch migration (80–90%): The bulk of devices are migrated in scheduled batches, typically aligned with shift changes or maintenance windows. Both cores are live, so devices not yet migrated continue working on the legacy system.
- Phase 3 — Stragglers (5–10%): Devices that were offline, in repair, or in storage during the main migration. We track these against the inventory until every device is accounted for.
What You Need to Prepare
To make device migration smooth, have the following ready:
- A current device inventory (or access to your asset management system so we can build one)
- MDM access if you use one (Jamf, SOTI, VMware Workspace ONE, etc.)
- Physical access plan for SIM swaps (shift schedules, docking station locations, technician availability)
- Application owners identified for validation sign-off
We handle the rest — SIM procurement, provisioning, configuration, testing, and validation.