TL;DR:
- LTE-M offers the best balance of bandwidth, latency, and mobility support, making it the default choice for asset tracking, wearables, and anything that moves
- NB-IoT has the lowest power consumption and best penetration into basements and buildings, but no support for voice or handover across cells
- LTE Cat-1 (and Cat-1 bis) delivers the highest bandwidth and lowest latency of the three, at higher module cost and power draw
LoRaWAN and Sigfox get a lot of attention in the LPWAN space, but for most production IoT deployments in Europe and North America, the choice comes down to three 3GPP-standardised cellular technologies: LTE-M, NB-IoT, and LTE Cat-1. All three use existing LTE infrastructure. All three are covered by mobile operators without specialist network deployment. The differences that matter are in the technical details.
The Standards at a Glance
| Feature | LTE-M (Cat-M1) | NB-IoT (Cat-NB1/2) | LTE Cat-1 (bis) |
|---|---|---|---|
| Peak downlink | ~1 Mbps | ~250 kbps | ~10 Mbps |
| Peak uplink | ~1 Mbps | ~20 kbps (multi-tone) | ~5 Mbps |
| Typical latency | 10-15ms | 1.5-10s | <10ms |
| Voice support | Yes (VoLTE) | No | Yes |
| Mobility/handover | Yes | Limited (no handover) | Yes |
| Power saving modes | eDRX, PSM | eDRX, PSM (more aggressive) | Basic DRX |
| Module cost | Medium | Low | Medium-high |
| Antenna | Single or MIMO | Single | Single (Cat-1 bis) or MIMO |
LTE-M: The General-Purpose Workhorse
LTE-M (also called LTE Cat-M1 or eMTC) was designed for IoT devices that need to work on existing LTE networks with lower bandwidth and power requirements than a smartphone, but more capability than the deepest LPWAN options.
The key differentiator from NB-IoT is mobility support. LTE-M supports cell handover, meaning a device can move between cell towers while maintaining a connection. For asset tracking, fleet management, or wearables that follow users around cities, this matters enormously. NB-IoT devices that move between cells can lose connectivity or face extended reconnection times.
LTE-M also supports half-duplex voice (VoLTE), opening use cases like emergency buttons, wearables with voice communication, and some industrial handheld devices.
Battery life on LTE-M is excellent for periodic-reporting devices. Power Saving Mode (PSM) allows devices to stay connected in a low-power state for hours or days between transmission windows. A tracker reporting location every 15 minutes can easily run years on a small lithium battery.
Ideal use cases: asset tracking, vehicle fleet management, medical wearables, smart city sensors that span multiple cells, remote industrial equipment.
NB-IoT: Maximum Battery Life, Minimum Cost
NB-IoT was designed for the most resource-constrained devices imaginable: fixed sensors reporting small payloads infrequently, often in locations with marginal coverage.
The advantage of NB-IoT comes from its extremely narrow bandwidth (180 kHz) and the ability to use repetition coding to punch through walls, underground conduit, and basement installations that would prevent LTE-M signals from reaching. In building penetration tests, NB-IoT consistently outperforms LTE-M in the most challenging locations.
Power consumption on NB-IoT can be extraordinary. A smart meter or water sensor transmitting a small payload once per hour can achieve battery life measured in 10+ years with properly implemented PSM and eDRX configurations.
The limitations are real. No handover means a device moving between cells will disconnect and reconnect, making NB-IoT unsuitable for mobile applications. High latency (connections can take seconds to establish after waking from PSM) rules out real-time control applications. Uplink bandwidth is fine for sensor payloads but insufficient for anything involving firmware OTA updates of significant size.
Ideal use cases: smart metering (electricity, gas, water), building sensors (temperature, occupancy, air quality), agricultural soil sensors, fixed infrastructure monitoring.
LTE Cat-1 and Cat-1 bis: When You Need More Bandwidth
LTE Cat-1 predates both LTE-M and NB-IoT and targets IoT applications that need genuine LTE-level bandwidth and low latency but don’t need the full specification of a smartphone modem.
It delivers up to 10 Mbps downlink, supports voice, and has very low latency. Module costs were historically higher because Cat-1 requires a two-antenna implementation (MIMO). Cat-1 bis (Release 13) added a single-antenna option that dramatically reduced module cost, making Cat-1 bis competitive with LTE-M for devices where a second antenna isn’t practical.
Power consumption is higher than LTE-M or NB-IoT. Cat-1 is not suitable for battery-powered devices with long deployment cycles.
Ideal use cases: POS terminals, ATMs, industrial controllers that need real-time data, in-vehicle infotainment systems, vending machines, devices that process and upload images or larger data payloads.
Coverage Considerations
In the UK and Western Europe, both LTE-M and NB-IoT are broadly deployed by the major operators. EE, Vodafone, and Three UK all offer NB-IoT and LTE-M. Check your target deployment geography against operator coverage maps before committing to a technology, as rural and indoor coverage varies.
In the US, Verizon and AT&T have deployed LTE-M nationally; T-Mobile uses NB-IoT. This historically meant that US LTE-M devices on Verizon could not roam to T-Mobile, though the situation is improving as operators align.
Making the Decision
For anything that moves: LTE-M.
For fixed sensors on a battery with extreme life requirements: NB-IoT.
For high-bandwidth industrial or commercial applications: Cat-1 bis.
For applications needing voice: LTE-M or Cat-1.
One practical note: dual-mode modules (LTE-M + NB-IoT in the same chip) have become common and affordable. They let your firmware select the optimal technology based on signal conditions, and simplify global deployment where different operators prioritise different standards.