What Is eRedCap?

eRedCap is not a niche edge case in the 3GPP roadmap. It is the answer to one of the largest transition challenges in cellular IoT: what replaces the hundreds of millions of LTE Cat-1 and Cat-1bis modules deployed globally in smart meters, asset trackers, vehicle telematics, industrial M2M gateways, and point-of-sale terminals when 4G networks are eventually wound down.

This page covers the technical specification in full, explains where eRedCap sits in the 3GPP IoT family, distinguishes it precisely from its predecessors and relatives, and explains the hardware and network deployment trajectory through to 2027 and beyond.

Where eRedCap Sits in the 3GPP IoT Family

3GPP has progressively defined a layered set of cellular IoT standards from extremely low data rate applications (NB-IoT) through to full 5G NR. eRedCap occupies the middle tier – above LPWAN but well below mainstream 5G – specifically designed for devices that need more than NB-IoT or LTE-M can deliver, but do not justify the complexity and cost of full 5G NR or even Release 17 RedCap.

eRedCap vs RedCap: The Key Differences

eRedCap is frequently conflated with RedCap (Release 17). They are related but distinct – eRedCap is not simply an update to RedCap but a separate, lower-tier device class defined in Release 18 to address a different market segment. Understanding the distinction is essential.

Release 17 RedCap (sometimes called NR-Light) was designed for wearables, industrial sensors, and video surveillance. It reduced complexity compared to a full 5G smartphone UE but remained a capable device with two receive antennas and 10-20 MHz minimum bandwidth – delivering around 150 Mbps peak downlink. That is comparable to a mid-tier 4G handset, not an IoT module.

Release 18 eRedCap takes the complexity reduction further – specifically targeting the much larger market of devices that only need Cat-1-equivalent throughput. The reductions from RedCap to eRedCap are:

eRedCap Technical Specification

The following parameters are defined in 3GPP Release 18. Figures marked NEW IN REL.18 are specific to eRedCap and not present in Release 17 RedCap.

Half-Duplex FDD Explained

One of the most commercially significant eRedCap features is HD-FDD support – half-duplex Frequency Division Duplex. In standard FDD operation, a device transmits and receives simultaneously on separate frequency pairs. This requires a duplexer – an expensive RF component that isolates the transmit and receive chains from each other.

HD-FDD allows eRedCap devices to use FDD spectrum (paired uplink/downlink frequencies) but transmit and receive at different times rather than simultaneously. The device switches between transmitting on the uplink frequency and receiving on the downlink frequency. This eliminates the need for the duplexer, reducing both BOM cost and the physical size of the RF front end.

The practical result is cheaper modules. Duplexers and diplexers are among the more expensive RF components in a cellular modem design. Removing the requirement to operate both simultaneously is directly analogous to the simplification that made LTE Cat-1bis cheaper than LTE Cat-1 – Cat-1bis also used a single antenna to eliminate one of the two required receive chains.

Power Saving in eRedCap

Battery longevity is critical for a large fraction of the IoT devices eRedCap targets. Smart meters, asset trackers, and environmental sensors frequently operate on primary batteries for years. eRedCap introduces and enhances several power saving mechanisms:

eDRX in RRC_INACTIVE State

This is specific to Release 18 and is not present in RedCap. Extended Discontinuous Reception (eDRX) in the RRC_INACTIVE state allows a device to sleep for extended periods while remaining registered to the network in a suspended state. Unlike the fully detached state of Power Saving Mode (PSM), the device can be paged and wake to receive data relatively quickly – without going through the full attach and RRC establishment procedure.

The practical advantage over PSM is latency: a device in PSM may be unreachable until its next scheduled wakeup cycle (potentially hours). A device using eDRX in RRC_INACTIVE can be woken by a network page within a configurable window, making it suitable for applications requiring occasional server-initiated communication.

Power Saving Mode (PSM)

PSM allows the device to enter a deep sleep state between scheduled reporting cycles. It remains registered but unreachable. Ideal for sensors reporting once per hour or less, where network-initiated contact is not required between scheduled uploads.

Connected Mode eDRX (C-eDRX)

Allows a device in RRC_CONNECTED state to sleep for extended periods between downlink monitoring cycles, reducing the wake-up duty cycle without a full state transition.

Full Comparison: eRedCap vs the IoT Standards Family

Why eRedCap Requires 5G Standalone

eRedCap devices cannot operate on a 5G Non-Standalone (NSA) network. NSA uses a 4G LTE core network (EPC) with 5G NR radio access layered on top as an additional carrier. The 5G NR radio in an NSA network is an enhancement – the core network functions (authentication, session management, policy, mobility) remain 4G. eRedCap’s reduced complexity signalling and its power saving features – particularly eDRX in RRC_INACTIVE – require the 5G Core (5GC) to function correctly.

5G SA deployment is progressing steadily. In the UK, EE and Vodafone have live 5G SA networks. Globally, major operators in South Korea, Japan, China, the United States, and across Europe have deployed or committed to 5G SA. The eRedCap hardware availability timeline (2026 onwards) aligns closely with the period in which 5G SA coverage will be sufficiently widespread to make eRedCap commercially viable at scale.

Hardware Landscape: Chipsets and Modules

The eRedCap chipset and module ecosystem is forming ahead of commercial network deployment. Key developments as of 2025-2026:

• Qualcomm: The Snapdragon X35 supports Release 17 RedCap. A successor addressing eRedCap (Rel.18) is in development. Qualcomm has been the leading chipset vendor for RedCap adoption.
• MediaTek: Active in the 5G IoT chipset space with RedCap silicon; eRedCap development in progress.
• Telit Cinterion: A significant module vendor with an eRedCap roadmap alongside existing Cat-1bis and RedCap portfolio. Their FE910C04 uses the Qualcomm X35 (RedCap).
• Sequans Communications: Specialist IoT chipset vendor with established NB-IoT and LTE-M silicon; 5G NR IoT roadmap includes eRedCap.
• Nordic Semiconductor, u-blox, Fibocom, Sierra Wireless, Quectel: All active in cellular IoT module supply chains with eRedCap on product roadmaps.

The first commercial eRedCap modules are expected in M.2 and LCC form factors, targeting industrial and automotive integrations. Consumer IoT device formats (compact SIP modules, LGA packages) will follow as volumes develop through 2027.

3GPP Release Timeline and eRedCap Roadmap

eRedCap Target Applications

eRedCap is purpose-built for applications in the 1-10 Mbps throughput tier that require cellular connectivity with reasonable latency but not the full complexity of mainstream 5G. The use case profile closely mirrors the existing LTE Cat-1 and Cat-1bis installed base.

Migrating from LTE Cat-1bis to eRedCap

For device designers and procurement teams currently specifying LTE Cat-1bis hardware, eRedCap is the natural forward specification – but the timeline matters. LTE Cat-1bis remains the right choice for any design that needs to ship and operate reliably today. The eRedCap ecosystem is not yet commercially mature.

The practical migration path is:

1. Short term (now to 2026): Specify Cat-1bis for devices shipping today. Good global coverage, proven module supply chain, extensive operator certification. Use Cat-1bis modules with an eye to end-of-life planning around 2030-2032 as 4G spectrum refarming accelerates.
2. Medium term (2026-2027): Evaluate first-generation eRedCap modules as they emerge. Prioritise dual-mode designs (Cat-1bis + eRedCap) for products with long lifecycle requirements. Confirm 5G SA coverage in your target deployment regions before committing.
3. Long term (2027+): eRedCap becomes the default mid-tier IoT specification as 5G SA coverage becomes widespread and module costs converge with Cat-1bis. Legacy LTE Cat-1/Cat-1bis devices face increasing migration pressure as operators accelerate 4G wind-down.

eRedCap and eSIM / eUICC

eRedCap devices are fully compatible with eSIM and eUICC provisioning. The GSMA SGP.32 specification – IoT eUICC architecture – is directly applicable to eRedCap devices, enabling over-the-air SIM profile management without physical SIM replacement. This is relevant for large-scale IoT deployments where physical SIM changes are operationally expensive.

For more on eSIM in the IoT context, see euicc.co.uk and the GSMA’s SGP.32 IoT eSIM specification documentation.

Network Slicing and 5G Core Benefits

Because eRedCap requires a 5G Standalone core, devices automatically gain access to 5G Core features that are unavailable on 4G LTE. The most commercially relevant for IoT is network slicing.

Network slicing allows operators to partition a single physical network into multiple virtual networks, each with different QoS characteristics. An eRedCap smart meter deployment could be placed on a slice optimised for high device density, low-bandwidth, high-reliability communications – entirely separate from the slice used by 5G smartphones or broadband CPE. This is a significant capability for critical infrastructure operators who need assured service levels for grid communications or SCADA telemetry.

For more on 5G network slicing and its applications in IoT, see 5gslicing.co.uk.

eRedCap, RedCap, and the Wider 5G Reduced Capability Family

It is worth being precise about terminology, as the marketing language in this space can be loose:

• RedCap = 3GPP Release 17. NR-Light. ~150 Mbps. 2 Rx antennas. Wearables, industrial sensors, video surveillance. Hardware available from 2024.
• eRedCap = 3GPP Release 18. Enhanced Reduced Capability. ~10 Mbps. 1 Rx antenna. 5 MHz bandwidth. LTE Cat-1 replacement. Hardware from 2026.
• ultraRedCap = informal term for Release 19 NTN-capable 5G NR IoT devices with satellite fallback potential. Not a 3GPP official term. In development.

These are three distinct device classes at different points in the standardisation and commercialisation cycle. For the Release 17 RedCap standard, operator deployment coverage and available hardware, see 5gredcap.co.uk.

Related Standards and Resources