Utilities’ transition to a smarter, more resilient and decentralized electrical grid requires a robust, scalable and secure communications network. 5G has enabled an evolution of connectivity. Its high-performance configurations like enhanced mobile broadband (eMBB) and ultrareliable low-latency communication (URLLC) are generational upgrades, but they are often out of proportion in capability and cost for many utility use cases. Conversely, legacy cellular user equipment (UE) categories like long-term evolution (LTE) Cat-1 and Cat-M1, while effective, face an uncertain future as networks move toward 5G standalone (SA) architectures.

RedCap was initially specified in 3rd Generation Partnership Project (3GPP) Release 17 (Rel-17) and known variously as NR-Light or NR-Lite. It is specified to enable performance for mid-tier Internet of Things (IoT) use cases. It provides a cost-effective and power-efficient migration path for UE that needs more bandwidth than NB-IoT or Cat-M1 provide but does not require the full performance capabilities of 5G. With the subsequent introduction of enhanced RedCap (eRedCap) in 3GPP Release 18 (Rel-18), the technology is further optimized for lower cost and power consumption, making 5G accessible to a vast new range of grid devices.

This paper provides a technical overview of RedCap and eRedCap — collectively referred to here as RedCap unless highlighting a technical difference between the two — and explores their capabilities, compares them to 4G, and analyzes why this new 5G UE category is a promising solution for the future of electric utility connectivity.

RedCap is a new category of 5G UE designed with intentional reductions in capability. The term “reduced capability” is not a pejorative; rather, it signifies a strategic optimization. By relaxing certain 5G requirements, RedCap achieves an efficient balance of performance, power consumption and 5G UE cost reduction that is well suited for utilities.

Primary reductions include:

• Reduced bandwidth. RedCap UE operates with a maximum channel bandwidth of 20 MHz, and eRedCap UE operates with a maximum channel bandwidth of 10 MHz in sub-6 GHz bands, a significant reduction from the 100+ MHz used by eMBB UE.
• Fewer antennas. Instead of the two or more antennas typically required for 5G, RedCap requires only one or two receive antennas, simplifying 5G UE design and lowering cost.
• Simpler duplex operation. RedCap supports half-duplex frequency division duplex (FDD) operation, which simplifies the radio frequency front end and reduces power draw in comparison to the simultaneous transmission and reception required by full-duplex FDD.
• Lower-order modulation. Processing requirements are relaxed, with 64QAM being optional, which lessens the complexity and power needs of the UE’s internal chipset.

A 5G UE is intended to operate with a minimum of two or four antennas, utilizing several megahertz of spectrum. With 4G, UE can operate with just one or two receive and transmit antennas. Due to this difference, there can be a large performance gap between a 4G UE and a 5G UE. It is important to understand that because utilities typically prioritize building out network coverage at the lowest possible cost, the preferred spectrum frequencies for utility applications are bands that are sub-1 gigahertz (GHz). Due to design and physical constraints, UEs cannot practically be built to support 4x4 MIMO for sub-1 GHz bands.

The RedCap reductions from the original 5G UE performance requirements translate into a smaller UE footprint, longer battery life and lower cost, making RedCap a compelling technology for deploying sensors, meters and controllers at scale on a 5G network.

For years, utilities have leveraged 4G LTE technologies like Cat-M1, Cat-1, Cat-4 and NB-IoT for grid communications. RedCap is not designed to immediately replace these technologies, but rather to provide a strategic evolution. RedCap offers a 5G-native solution that combines many of the top attributes of its predecessors with 5G advantages (see Figure 1).

*Data rates represent theoretical maximums. Real-world performance will vary based on factors such as network congestion, signal strength and specific device configurations.
**MIMO (DL): Multiple-Input Multiple-Output Downlink. This correlates to the number of simultaneous receive antennas of the UE. 1R means one receive antenna. 2R means two receive antennas. Theoretically, downlink throughput can increase with more receive antennas.
***Maximum Coupling Loss (MCL) is a 3GPP standardized metric that quantifies the maximum tolerable path loss in decibels (dB) between the radio access network (RAN) and UE. A UE with a higher MCL value can sustain reliable communication over greater distances or through higher levels of signal attenuation, resulting in a larger effective coverage area than one with a lower MCL.

Figure 1: Comparative attributes of grid communication technologies.

When comparing the RedCap categories with low-power wide area network (LPWAN) technologies such as Cat-M1, there is a drawback. LPWAN solutions have higher typical MCL values, while RedCap UE has lower MCL values. Cat-M1’s high MCL means this type of UE can tolerate more path loss, either from ground clutter or from the overall distance to a radio access network (RAN) site/sector. Higher MCL values can positively influence overall costs with RAN site build-outs; the trade-off is increased latency and reduced data rates. While Cat-M1’s extended coverage behavior is attractive, there is a performance cost to consider.

Deploying Cat-M1 requires using new overhead signaling on the RAN, adding to the LTE control plane signaling burden already in place to support “regular” broadband devices. This split configuration statically assigns radio resources for Cat-M1, regardless of whether the Cat-M1 UE is active or idle. This configuration has the negative effect of lowering the overall performance for all users that are being served by that RAN site/sector. Cat-M1 also requires 4G core network functions even when operating on a 5G SA network, which means a utility’s 5G SA network will need specific support for legacy 4G core functionality during the life of its Cat-M1 UE deployments.

Unlike Cat-M1, 5G RedCap UE leverages the same control plane signaling as the broadband 5G UE categories, and the RedCap resources are dynamically assigned during UE attachment negotiations. This reduces complexities, and users on the same RAN site/sector do not experience the same reduction in performance that accompanies a Cat-M1-enabled network.

Key takeaways from the table in Figure 1:

• RedCap’s efficient use of network resources makes it a good 5G-native alternative to Cat-M1. Furthermore, RedCap UEs are natural replacements for mid-tier LTE UE categories.
• While NB-IoT and Cat-M1 can coexist with 5G for some time, this configuration requires legacy 4G elements and segregated spectrum (for Cat-M1 specifically).
• By operating on a 5G SA network, RedCap UE can leverage advanced features like slicing to segregate families of flows, support enhanced positioning and incorporate end-to-end security. These features are not available on 4G networks.

To understand the strategic importance of RedCap, it helps to understand the three primary service categories of 5G:

• eMBB (enhanced mobile broadband). Focused on maximizing data rates and capacity for applications like high-definition video streaming and broadband access.
• URLLC (ultrareliable low-latency communication). Designed for mission-critical applications requiring near-instantaneous guaranteed data delivery, such as autonomous vehicles and direct transfer trip.
• mMTC (massive machine-type communications). Built to support immense connection densities of low-power and low-data UEs, such as sensors and meters.

RedCap carves out a new domain within this framework. It sits comfortably between the high cost and performance of eMBB/URLLC and the low power and low data focus of mMTC. This position is precisely where the bulk of modern utility applications lie, requiring a balance of reliable connectivity, moderate throughput and sustainable cost.

The greatest advantage of RedCap for electric utilities is its alignment with the practical needs of grid modernization. A private 5G SA network powered by RedCap UE can address a wide spectrum of utility use cases with a single, converged cellular generation (5G).

Utility use cases for RedCap include:

• Distribution automation (DA). Devices like reclosers, capacitor bank controllers and fault circuit indicators require reliable, low-latency communications to operate effectively. RedCap’s latency (~10-20 ms) is a significant improvement over Cat-M1 and is more than sufficient for most DA schemes, while 5G support for network slicing can guarantee priority traffic for these critical assets.
• Advanced metering infrastructure (AMI). While first-generation smart meters could be served by NB-IoT, next-generation AMI requires more bandwidth for real-time data, remote disconnects/reconnects and firmware updates. eRedCap, with its peak data rate of 10 Mbps and power-saving modes, is perfectly sized for this application, offering a cost-effective and future-proof solution. RedCap UE has reduced coverage when compared to NB-IoT and Cat-M1, a delta that vendors perhaps could address by implementing workarounds with hybrid mesh-RedCap meters.
• Substation and field area networking. RedCap is an excellent connectivity option for intelligent electronic devices, remote terminal units (RTUs) and pole tilt sensors. It can support the backhaul of sensor data for grid monitoring and analytics, as well as provide connectivity for video surveillance cameras at remote sites.
• Renewable energy integration. Managing distributed energy resources (DER) like solar panels and battery storage requires constant communication for monitoring and control. RedCap continues to provide the necessary throughput and reliability as prior 3GPP technologies, but in an effective utility-scaled 5G UE for a 5G SA network.
• Workforce enablement. Field crews can benefit with a native 5G RAN configuration because RedCap and other 5G mobile UEs are seamlessly supported without a comparable capacity impact in a Cat-M1-enabled network.

The RedCap ecosystem is maturing at an accelerated pace, driven by strong demand from industrial, automotive and utility sectors.

Does it replace NB-IoT and Cat-M1? Not immediately, but it does provide a clear, long-term migration path. For the next several years, NB-IoT and Cat-M1 will continue to be supported as part of the 5G framework. However, as carriers repurpose spectrum and decommission older 4G networks, RedCap is poised to become the default standard for mid-tier and lower-power 5G UE.

There are different classes of RedCap UE. The initial Rel-17 RedCap specification provides the baseline for UE requiring up to 220 Mbps. The Rel-18 eRedCap standard defines a lower-tier UE, optimized for cost and power, to directly address the 10 Mbps market currently served by LTE Cat-1. Future releases are expected to introduce further optimizations, potentially including support for non-terrestrial networks (NTN) and even lower power modes.

In terms of availability, RedCap (Rel-17) UE is commercially available from major vendors like Qualcomm, Semtech and Telit Cinterion. eRedCap (Rel-18) UE is expected to become commercially available in the second half of 2026 or 2027.

3GPP RedCap is an evolution of the 5G UE standards that offers a path to integrating IoT and mid-tier data applications into an efficient 5G SA architecture. The performance gains and, more important, the dynamic and efficient use of network resources make RedCap a compelling successor to legacy 4G solutions.

This technological evolution is not without trade-offs. The impressive MCL values for Cat-M1 and NB-IoT are a direct consequence of their design, prioritizing deep coverage over performance. Utilities must confront a crucial question: Is the move away from Cat-M1, with its superior coverage, a step backward in some respects? For a utility whose primary challenge is reaching remote or underground assets, the burden of potentially requiring a denser RAN network to achieve the same reach with RedCap is a critical consideration.

Furthermore, while RedCap modules will be substantially more cost-effective than their 5G broadband counterparts, it is highly unlikely they will match the lower prices of mature Cat-M1, NB-IoT and other LTE categories. The decision represents a complex balance of factors. For many applications, Cat-M1 is and may remain good enough — a proven, cost-effective solution for low-bandwidth needs where coverage is critical.

The choice is not about whether RedCap is better, but about which technology is the right solution for a utility’s intended use cases. The path forward requires a nuanced evaluation, weighing the future-proofing of the network and security efficiencies of a 5G native solution against the tangible realities of continuing with Cat-M1: increased core network complexity and cost, improved coverage of Cat-M1 endpoints, and Cat-M1’s likely reduced module costs.