Coverage, power, and bandwidth tradeoffs

Key takeaways

Choosing a cellular IoT technology is fundamentally an exercise in managing tradeoffs. You cannot maximize coverage range, minimize power consumption, and maximize data throughput all at the same time — every technology makes deliberate decisions about which dimension to prioritize. This micro-module explains how these three dimensions interact so you can evaluate the right balance for your specific product.

What you’ll learn

Why coverage, power, and bandwidth form a three-way tradeoff

Think of three competing dimensions: coverage range (how far and how deep the signal reaches), battery life (determined by power consumption), and data throughput (how much data you can send and how fast). Optimizing one dimension typically comes at the expense of another. A narrower channel concentrates energy for deeper penetration but limits throughput. A wider channel increases data rates but requires more power and reduces range. Each cellular IoT technology represents a different point in this tradeoff space.

How NB-IoT achieves the deepest coverage penetration

NB-IoT achieves the deepest coverage of any cellular IoT technology by concentrating energy into a narrow 200 kHz channel. It supports a Coverage Enhancement Mode that adds up to 20 dB of additional link budget compared to standard LTE. This is the equivalent of penetrating several more concrete walls. This makes NB-IoT the strongest option for devices deployed in basements, underground parking structures, utility vaults, and deep inside buildings. LTE-M also has good indoor coverage but does not match NB-IoT's extremes. Standard 4G LTE and 5G RedCap offer the same outdoor coverage as the broader cellular network but lack dedicated deep-indoor penetration features.

How PSM and eDRX enable multi-year battery life

Both NB-IoT and LTE-M support two critical 3GPP-defined power-saving mechanisms: Power Saving Mode (PSM) and extended Discontinuous Reception (eDRX). PSM puts the device into deep sleep where the radio is completely shut down between transmissions. Current draw drops to microamps, comparable to the battery's self-discharge rate. The device wakes only to transmit, then returns to sleep.

eDRX allows the device to negotiate longer paging cycles with the network: instead of listening for incoming messages every few seconds, it can listen every few minutes or even hours. eDRX can extend battery life 10–70x for stationary devices.

Combined, PSM and eDRX enable multi-year battery life. Standard 4G LTE does not support these modes in most deployments. 5G RedCap supports them but its higher baseline power draw (wider bandwidth and more complex processing) means it currently cannot match NB-IoT or LTE-M.

How bandwidth directly determines throughput and power consumption

The relationship is straightforward: more bandwidth means more throughput, but also more power consumption. NB-IoT's 200 kHz channel limits it to about 170 Kbps which is enough for sensor readings and small payloads, but not for firmware updates or image transfers. LTE-M's 1.4 MHz channel delivers up to about 1 Mbps, sufficient for firmware over-the-air (FOTA) updates and moderate payloads. Standard 4G LTE at 20 MHz delivers up to 150 Mbps, and 5G RedCap at 20 MHz achieves about 220 Mbps thanks to 5G NR's more efficient air interface. Each step up in bandwidth increases capability but also increases the power required to process and transmit the wider signal.

How to match tradeoff priorities to real deployment requirements

If you need a device to last 10 years on a single battery and only report data once an hour, NB-IoT's extreme power efficiency and deep coverage make it the clear choice, even though throughput is limited. If your device moves, needs periodic firmware updates, or sends larger data payloads, LTE-M's balance of power efficiency, mobility, and throughput is the sweet spot. If your device streams video, runs a gateway, or needs near-real-time performance, you need 4G LTE or 5G RedCap. You’ll also need a reliable power source (mains, solar with storage, or a vehicle battery).

Lesson 1.4 Self-assessment

Frequently asked questions