The "radio access technology" is the part of cellular that gets bits between your device and the cell tower. The choice you make here sets the upper bound on bandwidth, the lower bound on power consumption, and the breadth of coverage you can realistically expect. This article walks through each technology and where it fits in IoT.

Quick comparison

2G: GSM

Status: Sunsetting. Switched off in many countries (Australia, Switzerland, Singapore among others) and scheduled for shutdown in many more.

GSM was the first widely deployed digital cellular standard. For IoT, it's still relevant in two narrow contexts:

• Legacy fleets that have been running on 2G modems for years and aren't worth retrofitting.

• Coverage fallback in regions where LTE-M and NB-IoT haven't rolled out yet, usually emerging markets.

For new designs, don't pick 2G. Operators are reclaiming the spectrum, and devices deployed today on 2G will need replacement before they reach end-of-life.

3G: WCDMA / CDMA2000

Status: Sunsetting. Already switched off across the US, most of the EU, Australia, and much of Asia, with more shutdowns scheduled each year. Some networks remain live, mainly in emerging markets.

Don't include 3G in new designs. The remaining networks are being decommissioned faster than 2G in most regions, and a device deployed on 3G today will likely outlive the network it depends on. Existing 3G fleets need a migration plan.

4G: LTE

Status: Dominant. Available in essentially every country with cellular infrastructure.

LTE is the workhorse of IoT today. Most devices use plain LTE (Cat-1, Cat-4) for general-purpose connectivity:

• Cat-1 (~10 Mbps down, 5 Mbps up) is the entry point, cheap modules, decent throughput, broadly supported.

• Cat-4 (~150 Mbps down, 50 Mbps up) is what consumer hotspots and high-bandwidth IoT use.

• Higher categories (Cat-6, Cat-12, etc.) push bandwidth further but are rare in IoT.

If you're not sure what to use, LTE Cat-1 or Cat-4 is the safe default.

5G: NR (New Radio)

Status: Deployed in most major markets, expanding rapidly.

5G adds three things that matter for IoT:

• Higher bandwidth. Multi-gigabit throughput where the network supports it.

• Lower latency. Single-digit millisecond round-trip in the best case.

• Network slicing. The ability to provision a logical "slice" of the network with guaranteed characteristics (bandwidth, latency, reliability).

Choose 5G if you need real-time video, very high throughput, or guaranteed latency. For sensor reporting at kilobyte-per-day scale, 5G is overkill, LTE-M or NB-IoT is the right answer.

LTE-M: LTE Category M (Cat-M1)

Status: Deployed in most LTE markets in North America, Europe, and parts of Asia.

LTE-M is LTE optimised for IoT. It runs on existing LTE infrastructure but uses a narrower band, which means:

• Lower power. Years of battery life on small batteries, given infrequent transmission.

• Lower throughput. ~300 kbps typical; fine for sensor data, command-and-control, voice (yes, LTE-M supports voice), but not video.

• Better in-building penetration. The narrower band gets through walls better than full LTE.

• Mobility supported. LTE-M handles handover between cells, so it works for moving devices (asset tracking, vehicles).

LTE-M is the right answer for most IoT projects where battery life matters more than throughput.

NB-IoT: Narrowband IoT (Cat-NB1, Cat-NB2)

Status: Widely deployed in EU, China, and parts of Asia. Patchier in North America.

NB-IoT is the more aggressive cousin of LTE-M:

• Even lower power. Devices can sleep for hours between transmissions and last 10+ years on a battery.

• Even lower throughput. ~20–250 kbps. Designed for kilobytes-per-day workloads.

• Best-in-class deep coverage. Reaches into basements, underground meter pits, and rural fringe areas where LTE-M can't.

• Limited mobility. NB-IoT was designed for stationary devices; handover is slower or unsupported on some networks.

Pick NB-IoT for smart meters, agricultural sensors, parking sensors, environmental monitors, anything that reports infrequently from a fixed location.

One caveat: NB-IoT roaming is patchy. If your devices need to operate cross-border, verify roaming support per country before committing.

LoRa / LoRaWAN

Status: Non-cellular. Operates on unlicensed spectrum (sub-GHz ISM bands). Requires LoRaWAN gateways.

LoRa isn't a cellular technology, but it competes with NB-IoT for the very-low-power, very-low-bandwidth corner of IoT.

• Very long range. Several kilometres in cities, tens of kilometres in rural environments.

• Very low power. Multi-year battery life is standard.

• Very low bandwidth. Bytes per message, not kilobytes.

• Unlicensed spectrum. Subject to interference, no QoS guarantees.

• Infrastructure required. You need LoRaWAN gateways within range, either your own or a public network operator's.

LoRa is great when you control the gateway infrastructure (a campus, a farm, a factory) or when a national LoRaWAN operator covers your area. Otherwise, LTE-M or NB-IoT typically wins because cellular coverage is already there.

Simbase doesn't operate LoRa networks; it's listed here for completeness when you're picking a connectivity stack.

How to choose

1. What's the device's data budget per day?

   • Bytes → NB-IoT or LoRa

   • Kilobytes → LTE-M or NB-IoT

   • Megabytes → LTE Cat-1 or Cat-4

   • Gigabytes → 5G

2. What's the device's power budget?

   • Mains-powered → any LTE/5G category

   • Years on a battery → LTE-M or NB-IoT

   • Decade on a battery → NB-IoT or LoRa

3. Where does the device need to work?

   • Globally → LTE Cat-1 (most universal) or LTE-M (great coverage in major markets)

   • Region-specific → check NB-IoT support per country

   • Building interiors / underground → NB-IoT or LTE-M

   • Rural / remote → LTE-M or LoRa

4. Is the device mobile?

   • Yes (vehicles, trackers) → LTE Cat-1, Cat-4, or LTE-M

   • No (meters, sensors) → NB-IoT becomes viable

Simbase support

Simbase SIMs work with all the cellular technologies above (2G and 3G where those networks are still live, 4G LTE, 5G NR, LTE-M, NB-IoT). Which technologies any specific SIM can use depends on the SIM profile and the device. See SIM Profiles for the per-profile coverage.

Common questions

Related

• SIM Profiles, which radio technologies each profile supports

• Data Roaming, how a SIM uses networks beyond its home operator

• Quality of service (QCI), what latency and throughput to expect once connected

• Coverage, which networks and technologies are available per country

• Diagnostics, check which technology a SIM is currently using