eRedCap vs LTE Cat-1bis: Migration Planning for IoT Device Designers

LTE Cat-1bis is the right choice for devices shipping today. It has proven module supply, global operator certification, and broad roaming support. eRedCap is the right specification for anything designed to last into the 2030s. These two facts are not in conflict – but they do require a deliberate planning position.

3GPP Release 18 was frozen in 2024. The eRedCap specification is complete. Chipset development is underway at Qualcomm, MediaTek and others. Commercial modules are expected from 2026, with wider availability through 2027. That timeline is close enough to demand attention from anyone in IoT hardware design or procurement today.

This post sets out what the transition means practically – the technical differences that matter for device design, the 5G SA network dependency, and a phased planning approach for teams currently specifying Cat-1bis hardware.

For a full technical overview of the eRedCap standard including specifications, comparison tables and SVG diagrams, see What is eRedCap?

What eRedCap Delivers Over LTE Cat-1bis

On headline throughput, eRedCap and LTE Cat-1bis look identical. Both deliver approximately 10 Mbps downlink and 5 Mbps uplink. Both use a single receive antenna. Both support half-duplex FDD operation. From an application data rate perspective, a device migrating from Cat-1bis to eRedCap will not notice a difference in normal operation.

The differences that matter are underneath the data rate:

Two of those rows deserve specific attention for device designers.

Power saving is a genuine gain

LTE Cat-1 and Cat-1bis have no Power Saving Mode (PSM) and no eDRX in RRC_INACTIVE. For devices that report infrequently – smart meters, environmental sensors, asset trackers with long reporting intervals – this is a meaningful limitation. The modem must stay awake and connected between reporting cycles, consuming power that primary batteries or small energy harvesters often cannot easily sustain.

eRedCap inherits PSM from the broader 5G NR IoT stack and adds a new feature not present in Release 17 RedCap: eDRX in RRC_INACTIVE state. This allows a device to sleep for extended periods while remaining registered without fully detaching from the network – reducing wakeup latency compared to PSM while consuming far less power than staying fully connected. For devices on a primary cell battery, this is a direct improvement in operational lifespan.

Network slicing opens new deployment models

Because eRedCap operates on a 5G Standalone core, devices have access to network slicing – the ability for operators to partition their network into virtual slices with different QoS characteristics. For utility-grade IoT (smart meters, SCADA, grid monitoring), a dedicated slice with guaranteed capacity, low latency and isolated traffic provides a level of service assurance that is simply not available on 4G LTE.

This is not hypothetical. UK operators are already offering network slicing capabilities on their 5G SA infrastructure. For critical infrastructure operators, this is a compelling reason to plan for eRedCap rather than extending Cat-1bis deployments.

The 5G SA Dependency – The Key Planning Constraint

eRedCap will not work on a 5G Non-Standalone (NSA) network. NSA – which accounts for the majority of current 5G consumer coverage globally – runs a 4G core (EPC) with 5G NR radio added as a second carrier. The eRedCap power saving mechanisms and reduced capability signalling require the 5G Core (5GC). Without SA, the device cannot attach.

This is the single most important planning constraint for any eRedCap migration. Before committing to eRedCap hardware for a specific deployment, you need to confirm:

• 5G SA coverage is available or committed in your target deployment geography
• Your target operator has a confirmed eRedCap device certification programme
• Your SIM provisioning and APN configuration is aligned with the operator’s 5G SA infrastructure
• Your fallback strategy is defined for locations without 5G SA (LTE fallback or dual-mode module)

In the UK, EE and Vodafone have live 5G SA networks today. Three UK and O2 are building SA capability. Globally, major operators in South Korea, Japan, China, Germany and the United States have committed 5G SA roadmaps. The picture by 2026-2027 – when eRedCap modules ship at volume – will be substantially better than today.

Chipset and Module Availability Timeline

3GPP Release 18 being frozen does not mean chips are shipping. The path from specification freeze to volume commercial modules typically runs 18-30 months, depending on chipset vendor timelines, operator certification requirements, and module vendor production cycles.

The current picture for eRedCap silicon:

• Qualcomm – The Snapdragon X35 (Release 17 RedCap) is in production. A Release 18 eRedCap successor is in development. Qualcomm has been the dominant chipset vendor for the first-generation RedCap ecosystem and is well-positioned for eRedCap.
• MediaTek – Active in 5G IoT chipsets with RedCap silicon in development. eRedCap roadmap in progress.
• Sequans Communications – IoT chipset specialist with established NB-IoT and LTE-M products. 5G NR IoT including eRedCap on roadmap.
• Telit Cinterion, Quectel, Fibocom, u-blox – Major module vendors all carrying eRedCap on product roadmaps for 2026-2027 availability.

Dual-Mode Designs: The Bridge Strategy

For devices with long design-to-deployment cycles or extended operational life requirements, the most robust approach through the transition period is a dual-mode module carrying both LTE (Cat-1bis) and 5G NR (eRedCap) capability. The device connects via eRedCap where 5G SA is available and falls back to LTE Cat-1bis where it is not.

This is not a new pattern. Dual-mode designs bridging 3G and 4G were common during the LTE rollout period. Several module vendors are already developing LTE + RedCap dual-mode products; eRedCap variants will follow. The additional BOM cost is typically modest compared to the operational risk of a connectivity gap in markets where 5G SA rollout is slower than planned.

For devices shipping in 2026-2027 with expected operational lifespans of five to ten years, dual-mode is worth the cost.

Industries Where the Transition Matters Most

Not all Cat-1bis deployments face the same urgency. The industries where eRedCap migration planning matters most are those with:

• Long device replacement cycles (utilities, infrastructure, grid metering)
• High device volumes where module unit cost is sensitive (smart meters, telematics)
• Battery-constrained designs where PSM and eDRX in RRC_INACTIVE are valuable (remote sensing, environmental monitoring)
• Critical reliability requirements where network slicing is commercially useful (SCADA, industrial M2M, energy grid)

Smart metering is the largest single category. UK smart meter rollout has placed tens of millions of Cat-1 and Cat-1bis connected devices in the field with expected service lives extending well into the 2030s. New meter designs being specified now will need to address the 4G wind-down timeline explicitly.

What to Do Now

The most useful action today is not a hardware decision – it is a supply chain conversation. Talk to your module vendor about their eRedCap roadmap and form factor compatibility plans. Talk to your target operators about their 5G SA coverage commitments in your specific deployment geographies. Get those answers on record before the first eRedCap RFQs land.

eRedCap is not a disruption to plan around. It is a straightforward standards evolution. The organisations that treat it as such – and plan the transition with the same deliberateness they applied to 2G-to-3G and 3G-to-4G migrations – will manage it cleanly.

For the full technical specification of the eRedCap standard, see What is eRedCap? – 3GPP Release 18 Explained.

Sources: 3GPP Release 18 | GSMA IoT | Telit Cinterion