Managing eSIM Profiles in Massive IoT: Addressing the Latency Challenge

For decades, SIM cards — or Subscriber Identity Modules — have served mobile phone users well, enabling easy switching between devices. However, traditional SIMs aren’t always ideal for other device types, especially those that don’t require regular replacement. This is particularly true in the Internet of Things (IoT), where devices are often deployed at scale, in groups, and have long service lifespans.

In these cases, using physical SIMs presents logistical challenges. Managing the supply chain for both the device and the SIM adds complexity. Moreover, as devices age, switching connectivity providers becomes harder if it depends on replacing a physical SIM.

Cellular IoT devices vary widely in form factor, capabilities, and deployment context. Broadly, we can divide them into two categories:

• Unconstrained Devices: These include connected cars, industrial equipment, and agricultural machinery. They typically have ample power, memory, and compute, and often remain continuously connected.
• Constrained Devices: These are cost-sensitive, limited in compute, memory, and power, and built for narrowband, low-throughput use cases. This category is known as Massive IoT.

Why eSIM for Massive IoT is Different

Massive IoT devices exhibit several defining characteristics:

• Deployed at very large scale (up to millions of units)
• Minimal bill of materials, especially for storage and compute
• Low bandwidth usage and infrequent data transmission
• Operate in deep indoor or rural environments
• No user interface and limited protocol support (often no SMS)
• Extremely low power consumption, designed for 10+ year lifespans

These traits make traditional device and connectivity management methods unsuitable. In particular, the power budget is highly constrained — and wireless communication is often the largest consumer of energy.

To address this, the 3GPP has standardized narrowband cellular technologies, such as NB-IoT and LTE-M (Cat-M1), which support efficient radio use. Devices on these networks typically stay offline most of the time, activating radios briefly and infrequently.

Managing eSIM Profiles in IoT

In constrained environments, embedded SIMs (eSIMs) offer clear benefits: no physical swap is needed, and profile management can be done remotely. However, the management mechanisms must be adapted to suit limited devices.

The GSMA’s SGP.31 and SGP.32 specifications define a modern framework for eSIM profile management in IoT:

• SGP.31: Defines the high-level architecture, roles, and interfaces
• SGP.32: Provides the normative implementation for constrained devices

These standards allow profile management over several protocols:

Among these, LwM2M is particularly well suited for Massive IoT. It provides a structured application layer, built-in security (DTLS/OSCORE), notifications, and remote management capabilities — all optimized for low-power devices.

This framework supersedes SGP.02, the earlier standard used for consumer eSIM management, which lacks the protocol flexibility and IoT-specific optimizations offered by SGP.31/32.

The Latency Trade-Off

In typical Massive IoT deployments, eSIM profile changes are infrequent — often only once or twice over a device’s lifetime. As a result, devices should avoid maintaining constant connectivity to conserve power.

In devices with SMS support, servers can use SMS wake-up messages to request a connection. However, many Massive IoT devices do not support SMS and often remain offline for extended periods due to Power Saving Mode (PSM) or eDRX. This introduces a latency challenge: if a server requests a profile change, it may have to wait hours or even days until the device next connects.

Optimizing the Latency Trade-Off

Managing this latency–power trade-off is critical for practical eSIM management in Massive IoT. Several techniques can help:

1. Use of IPv6

IPv6 allows for globally unique, persistent addresses, which can improve addressability across power cycles. In contrast, IPv4 addresses often change, especially in low-cost M2M deployments.

2. LwM2M-Based Addressability

LwM2M supports observation and notification models that allow devices to pull configuration updates upon waking. It also supports registration-based events, allowing the network or server to act when a device reconnects.

3. Network-Assisted Triggers

Instead of polling, the mobile network can inform the eSIM IoT Remote Manager (EIM) when a device becomes available. The EIM can then initiate profile management workflows while the device is online.

Massive IoT presents unique challenges for eSIM lifecycle management, particularly around minimizing power consumption while retaining the ability to switch connectivity providers. The GSMA SGP.31 and SGP.32 standards provide a robust framework for this, especially when implemented over efficient protocols like LwM2M and CoAP.

The Motive IMPACT IoT platform supports the full range of SGP.31/32-compliant management options, including patented mechanisms to address the latency–battery trade-off. This enables network operators and enterprises to maximize device lifespan, reduce costs, and retain flexibility in managing connectivity over the entire device lifecycle.