LTE-M vs NB-IoT vs 4G LTE vs 5G RedCap

Key takeaways

Once you have decided that cellular is the right connectivity choice for your IoT device, the next question is: which cellular technology? There are four major options today — LTE-M, NB-IoT, standard 4G LTE, and the newer 5G RedCap. This micro-module breaks down each one so you can distinguish their design goals, capabilities, and target applications.

What you'll learn

What NB-IoT is designed for and where it excels

NB-IoT (Narrowband IoT) uses just 200 kHz of bandwidth, making it the narrowest channel of any cellular technology. It was designed from the ground up for stationary devices that send small amounts of data infrequently: smart meters reporting hourly readings, soil moisture sensors updating every few hours, or parking space detectors. NB-IoT achieves peak download speeds of about 170 Kbps and has relatively high latency oftypically 1.6 to 10 seconds. It does not support mobility (no handover between cell towers) and cannot carry voice. What it offers is exceptional indoor penetration (164 dB maximum coupling loss) and the potential for 10+ year battery life. Module costs range from $5 to $12, making it economically viable for massive deployments of stationary sensors in deep indoor or underground locations.

How LTE-M adds mobility, voice, and faster data rates

LTE-M (LTE for Machines, also called Cat-M1) uses 1.4 MHz of bandwidth, about seven times more than NB-IoT. It was designed for IoT devices that need more capability: faster data rates (up to about 1 Mbps), lower latency (50–300 ms), full mobility with handover support, and voice over LTE (VoLTE). LTE-M is the go-to technology for asset trackers, wearables, personal emergency response devices, and alarm systems. It is the right choice when the device moves (vehicles, containers, people), when you need voice or SMS fallback, or when latency under one second matters. LTE-M is also the dominant LPWA technology in North America.

When standard 4G LTE is the appropriate choice

Standard 4G LTE (categories like Cat-1, Cat-4, and higher) offers significantly more throughput of up to 150 Mbps downlink for Cat-4. It supports full mobility, low latency, and can handle demanding applications like streaming video from a security camera, running a mobile router, or connecting an industrial gateway that aggregates data from dozens of local sensors. The tradeoff is higher power consumption and higher module cost ($20–40+). Standard 4G LTE is not designed for battery-powered devices. It is meant for devices with a reliable power source that need high throughput or real-time performance.

What 5G RedCap brings to IoT and how it differs from full 5G

5G RedCap (Reduced Capability), standardized in 3GPP Release 17, bridges the gap between high-throughput 5G NR (New Radio) and low-power LPWA technologies. It limits bandwidth to 20 MHz (compared to 100 MHz for standard 5G NR), reduces antenna count to 1–2 receivers, and uses simpler modulation — achieving approximately 65% lower modem complexity. Peak speeds reach about 220 Mbps downlink with latency comparable to standard 4G.

RedCap also inherits advanced 5G features like network slicing (dedicating virtual network resources to specific application classes) and enhanced positioning (centimeter-level accuracy by aggregating signals across frequency layers).

How Release 18 eRedCap targets even simpler IoT devices

Enhanced RedCap (eRedCap) in 3GPP Release 18 goes further in reducing complexity. It caps peak data rate at 10 Mbps (both downlink and uplink) and typically uses a single receive antenna. This targets direct replacement of LTE Cat-1 and Cat-1bis for the simplest IoT devices. Basic trackers, smart meters, and environmental sensors that need slightly more capability than NB-IoT or LTE-M but do not require full 5G performance.

How to position these four technologies on the capability spectrum

These four technologies sit on a spectrum from lowest-power, lowest-throughput to highest-capability: NB-IoT is for stationary, low-data, long-battery-life devices. LTE-M adds mobility, voice, and faster speeds for trackers and wearables. Standard 4G LTE handles high-throughput, always-powered applications. 5G RedCap brings 5G capabilities to IoT at lower complexity and cost than full 5G NR, with network slicing and enhanced positioning as key differentiators.

Lesson 1.3 Self-assessment

Frequently asked questions