Reference Guide · Cellular IoT
Choosing the Right Cellular Technology
for Your IoT Application
A practical comparison of 2G, 4G, 5G, LTE-M, and NB-IoT across the parameters that matter most when specifying connectivity for industrial, commercial, and infrastructure deployments.
2G (GPRS / EDGE)
4G LTE
5G NR
LTE-M (Cat-M1)
NB-IoT (Cat-NB)
Specification Comparison
| Parameter | 2GGPRS / EDGE | 4G LTECat-4 / Cat-6 | 5G NRSub-6 / mmWave | LTE-MCat-M1 | NB-IoTCat-NB1/2 |
|---|---|---|---|---|---|
| Data SpeedsTypical throughput range | 20-40 kbps typical; up to 80-100 kbps with EDGE | 5-30 Mbps typical; up to 150 Mbps peak | 100-300 Mbps typical; 300 Mbps-1 Gbps+ at peak | 200-400 kbps typical; up to 1 Mbps | 20-60 kbps typical; up to 250 kbps |
| Frequency BandsOperating spectrum | 850-1900 MHz | 700 MHz – 2.5 GHz (wide band selection) | Sub-6 GHz (e.g. 3.5 GHz) + mmWave where deployed | Band 20 (800 MHz), Band 8 (900 MHz) – extended range focus | 800 MHz, 900 MHz and select LTE bands – deep coverage priority |
| Channel BandwidthSpectrum per connection | 200 kHz per channel | 1.4 MHz – 20 MHz (scalable) | Up to 400 MHz with carrier aggregation | 1.4 MHz narrowband channel, optimised for low-power IoT | 180 kHz narrowband channel – minimal spectrum footprint |
| Power EfficiencyBattery life suitability | Basic – limited power-saving capability; not suitable for battery-only operation | Improved over 2G; DRX sleep modes available but still relatively power-hungry | Energy-saving and sleep modes supported; still higher draw than LPWAN | PSM and eDRX support – potential for years of operation from a single battery pack | Exceptional – PSM and eDRX with minimal standby current; designed for decade-long battery life |
| Signal PenetrationIndoor / underground reach | Basic indoor and outdoor coverage | Good indoor and outdoor performance at sub-1 GHz bands | Excellent at lower frequencies; mmWave limited to line-of-sight outdoors | Exceptional – deep indoor reach and underground capability via low-band operation | Outstanding – purpose-built for challenging environments including basements, vaults, and thick-walled plant rooms |
| LatencyRound-trip delay | Up to 300 ms – too slow for any time-sensitive application | 30-50 ms – acceptable for most IoT control and monitoring | 10-20 ms typical; sub-1 ms with URLLC – genuinely real-time capable | 100-150 ms – suitable for periodic reporting; not real-time control | 1.6-10 seconds – not intended for real-time use; designed for infrequent data bursts |
| Mobility SupportPerformance while moving | Basic voice-era handover – limited for fast-moving assets | Full mobility support up to 120+ km/h – solid for vehicles and fleet | Full mobility with advanced beam management | Moderate – supports handover but optimised for slow-moving or static assets | Minimal – designed for static or very slow-moving deployments |
| Network AvailabilityUK coverage status 2025 | Being phased out – EE, Vodafone, Three 2G sunset underway or complete | Mature, near-universal UK coverage – most reliable choice today | Growing – major urban areas and transport corridors well served | Good UK coverage via EE and Vodafone; improving | Strong UK coverage via EE, Vodafone, Three; BT Wholesale available |
| Typical ApplicationsPrimary use cases | Legacy telematics, basic SMS alerting, heritage M2M – replacing | Video surveillance, mobile workers, broadband failover, connected vehicles | Real-time automation, AR/VR, autonomous systems, dense urban IoT | Asset tracking, industrial monitoring, mobile sensors, wearables | Smart metering, environmental monitoring, static sensors, infrastructure monitoring |
Real-World Application Examples
Technology choice depends on three key variables: how much data the device sends, how often it sends it, and whether it runs from mains or battery. The examples below illustrate how those factors drive the decision in practice.
NB-IoT
Water Meter Network
Battery-powered meters installed in pavement chambers transmit a daily consumption reading. Deep signal penetration reaches below ground, PSM keeps current draw under 5 µA between reports, and a single AA cell lasts 10+ years.
LTE-M
Cold Chain Asset Tracker
A temperature logger fitted to a pharmaceutical shipment reports every 15 minutes and triggers an immediate alert if the threshold is breached. eDRX keeps the battery running across multi-day journeys while eSIM roaming handles cross-border coverage.
4G LTE
Remote Site CCTV
A construction site compound streams H.264 video from four cameras to a cloud VMS. 4G delivers the consistent throughput needed for reliable recording and live viewing, with a dual-SIM router providing MNO failover.
4G LTE
BESS / Grid-Scale Energy Storage
A battery energy storage system running DNP3 SCADA over TCP requires low-latency, always-on connectivity. A dual-SIM router with MWAN3 failover across two MNOs, backed by a third WAN path, delivers the resilience required by ENA and NIS obligations.
LTE-M
Industrial Sensor Array
Vibration, temperature, and pressure sensors on rotating plant equipment report periodically with occasional high-frequency bursts on anomaly detection. LTE-M provides the bandwidth headroom that NB-IoT cannot while still supporting years of battery operation.
5G NR
Autonomous Mobile Robots
AMRs operating in a distribution centre require sub-20 ms latency for real-time navigation commands and HD camera feeds for obstacle avoidance. 5G with network slicing delivers dedicated bandwidth guarantees that shared 4G cannot reliably provide.
NB-IoT
Environmental Monitoring Network
Solar-assisted nodes across a river catchment send hourly flood risk readings. Infrequent small payloads, remote locations with patchy coverage, and a 10-year deployment horizon make NB-IoT the only credible choice.
4G LTE
Fleet Telematics
HGVs transmit CAN-bus data, driver behaviour scores, and tachograph records in near-real-time. 4G provides the speed and nationwide coverage needed while Cat-M fallback ensures connectivity in rural and motorway fringe areas.
Quick Selection Guide
If your device is battery-only and sends small payloads
NB-IoT or LTE-M
Choose NB-IoT for static sensors sending under 1 kB per day. Choose LTE-M if the device moves, needs SMS, or occasionally needs higher throughput.
If you need video, broadband, or VPN throughput
4G LTE
Proven, near-universal UK coverage with sufficient throughput for all but the most demanding real-time applications. Dual-SIM with MWAN3 delivers resilience for critical sites.
If latency under 20 ms is genuinely required
5G NR
Only 5G with URLLC slicing delivers sub-10 ms. Verify coverage at your specific site – 5G availability outside major cities and transport corridors remains patchy.
If the device is in a basement, vault, or thick-walled plant room
NB-IoT or LTE-M
Both technologies operate with 20 dB additional link budget over standard 4G. Where even these fail, consider an external antenna routed to a wall penetration.
If you’re replacing legacy 2G / GPRS hardware
4G LTE or LTE-M
Avoid 2G entirely for new deployments – sunset is underway across UK networks. LTE-M is the natural migration path for low-data M2M; 4G for anything needing real throughput.
If the deployment is across multiple countries
LTE-M with eUICC
LTE-M with roaming eSIM (SGP.32 / eUICC) provides the most robust path for cross-border asset tracking – programmable MNO switching without physical SIM changes.
Glossary of Key Terms
PSM – Power Saving Mode
A 3GPP feature allowing a device to enter an extremely low-power dormant state between data transmissions. The device remains registered to the network but is unreachable until it wakes. Critical for multi-year battery operation in NB-IoT and LTE-M.
eDRX – Extended Discontinuous Reception
Extends the standard DRX sleep cycle from milliseconds to minutes or hours, allowing the device to remain reachable but check for downlink data far less frequently. Complements PSM by offering a middle ground between availability and power draw.
LPWAN – Low Power Wide Area Network
A category of wireless technologies optimised for long range, low power, and small payloads. NB-IoT and LTE-M are the cellular LPWAN standards; LoRaWAN and Sigfox are unlicensed alternatives. Cellular LPWAN benefits from licensed spectrum and existing network infrastructure.
URLLC – Ultra-Reliable Low Latency Comms
A 5G NR service category targeting sub-1 ms latency with 99.9999% reliability. Requires network slicing support from the operator. Relevant for industrial automation, remote surgery, and autonomous vehicle control but rarely deployed outside specialist private 5G networks today.
MWAN3
A multi-WAN load balancing and failover package for OpenWrt-based routers (including Teltonika RUT/RUTM series). Monitors each WAN interface independently and routes traffic based on configurable rules – enabling dual-SIM, dual-MNO resilience without dropping persistent TCP sessions when properly configured.
eUICC / eSIM
An embedded, reprogrammable SIM that can switch between MNO profiles over-the-air without a physical swap. SGP.02 covers M2M profiles (server-managed); SGP.32 is the new IoT-specific standard enabling lightweight, device-initiated profile management – key for global deployments.
Cat-M1 / Cat-NB1
3GPP LTE device categories defining modem capability. Cat-M1 (LTE-M) supports up to 1 Mbps and voice; Cat-NB1 (NB-IoT release 13) supports 250 kbps downlink. Cat-NB2 (release 14) doubled this to 127 kbps uplink. These categories determine which chipset and SIM tariff applies.
Link Budget (MCL)
Maximum Coupling Loss – the total signal attenuation a radio link can tolerate. NB-IoT achieves 164 dB MCL, vs 144 dB for standard LTE. Those 20 dB translate directly into penetration through walls, underground reach, and extended range in rural areas.
DNP3 / SCADA
DNP3 (Distributed Network Protocol 3) is a serial and TCP/IP protocol used in utility SCADA systems – common in electricity substations, water treatment, and energy storage. Runs on TCP port 20000. Requires always-on, low-latency connectivity; session drops cause control system alarms.
mmWave
Millimetre-wave spectrum above 24 GHz used in 5G NR for very high throughput at short range. Offers multi-Gbps speeds but attenuates rapidly through walls and rain. UK mmWave 5G is deployed in limited hotspot locations – largely unsuitable for wide-area IoT.
Carrier Aggregation (CA)
Combining multiple spectrum bands simultaneously to increase throughput – a key enabler of 4G Cat-6 (300 Mbps) and 5G peak speeds. Requires modem and network support for each band combination. The Teltonika RUTM55, for example, supports 4CA on LTE.
MNO Diversity
Using SIMs from two different Mobile Network Operators simultaneously, typically across separate modem interfaces. Where single-MNO signal is marginal or unreliable, MNO diversity is the most robust resilience strategy – particularly relevant for critical national infrastructure and energy sector deployments.