Choosing how a device connects is the decision that constrains everything else: how long the battery lasts, how much data it can send, how far it can be from infrastructure, what the hardware costs and what the monthly bill looks like. There is no best radio, only a best fit for a particular combination of range, power, data volume and environment. The technologies that matter for IoT each occupy a distinct region of that space.
This guide compares the main options on the axes that drive the decision, groups them by the kind of deployment they suit, and ends with a method for narrowing the choice. Individual protocol guides go deeper on each one.
The axes that matter
Range. From a few meters (Bluetooth, UWB) through a building (Wi-Fi, Zigbee, Thread) to kilometers (LoRaWAN, cellular) and anywhere on Earth (satellite IoT). Range depends on frequency, transmit power and the link budget of the system; sub-GHz radios penetrate walls and travel farther than 2.4 GHz ones at the same power.
Power. Whether a device can run on a coin cell for years, a battery for months, or needs mains. The determining factor is how much energy each transmission costs and whether the radio can sleep between transmissions.
Bandwidth. From a few bytes a few times a day (LoRaWAN, Sigfox) to video streams (Wi-Fi, 5G). High bandwidth and low power do not coexist.
Latency. Whether a command reaches the device in milliseconds, seconds, or whenever it next wakes. Matters for actuators and real-time control, not for a soil sensor.
Topology. Star topology, where every device talks to a central point, versus mesh network, where devices relay for each other. Mesh extends coverage indoors at the cost of complexity and, for relaying nodes, power.
Infrastructure and cost. Whether you need to deploy gateways, rely on a public network you pay for, or use whatever Wi-Fi is already there. Also the radio module cost and certification effort.
Short range: Bluetooth and UWB
Bluetooth Low Energy is the default for devices that pair with a phone: wearables, beacons, medical sensors, locks. It is cheap, universally supported by phones, and sips power. Its limits are range (tens of meters) and the need for a phone or hub to reach the internet. Bluetooth mesh extends it to lighting and building networks. The BLE guide covers the details.
UWB is a specialist option for precise indoor positioning, measuring distance to centimeters, used for asset location and secure keyless entry.
In the building: Wi-Fi, Zigbee, Thread, Z-Wave
Wi-Fi is everywhere, needs no extra hub and carries lots of data, which makes it the easy choice for mains-powered consumer devices and cameras. It is poor on batteries, because keeping an association alive is expensive, and it performs badly when hundreds of devices share one access point. Wi-Fi HaLow is a sub-GHz variant designed to fix both problems for IoT, with longer range and lower power, at the cost of needing dedicated access points.
Zigbee and Thread both build on the IEEE 802.15.4 low-power radio and form self-healing mesh networks where mains-powered devices route for battery-powered ones. Zigbee has a long track record in smart home and lighting and its own application profiles; Thread is newer, carries native IPv6 via 6LoWPAN, and is the low-power transport under Matter. Both need a hub or border router to reach the internet. The Zigbee guide and Thread guide compare them in depth.
Z-Wave is a sub-GHz mesh used mainly in home security and automation, with strong interoperability inside its own ecosystem.
Wide area, low power: LoRaWAN, NB-IoT, LTE-M, Sigfox
LPWAN technologies trade bandwidth for range and battery life: kilometers of reach, years on a battery, payloads of a few dozen bytes.
LoRaWAN uses unlicensed ISM band spectrum and the LoRa modulation, which lets a spreading factor trade data rate for range. You can run your own gateways and network server or use a public operator, which makes it attractive for campuses, farms and cities where a single organization owns the infrastructure. Downlink capacity is limited and regulatory duty cycle limits apply. See the LoRaWAN guide.
NB-IoT and LTE-M are cellular IoT standards from 3GPP that run on operator networks in licensed spectrum. No gateways to deploy, coverage wherever the operator provides it, and a SIM or eSIM per device with a data plan. NB-IoT is the lowest power and deepest penetrating; LTE-M offers more bandwidth, mobility and voice. The NB-IoT and LTE-M guide explains the trade-offs.
Sigfox is an operator-run ultra-narrowband network with very small messages; mioty and Wi-SUN are further options for industrial and utility networks.
High bandwidth and mobility: cellular and satellite
Standard LTE and 5G suit vehicles, cameras, gateways and anything that moves or streams. 5G RedCap is a reduced-capability 5G profile aimed at mid-range IoT devices that need more than LTE-M but less than a phone. Private 5G networks give factories and ports their own licensed-grade coverage with network slicing for traffic isolation.
Satellite IoT covers oceans, deserts and remote infrastructure where nothing else reaches, with small messages, higher cost and latency that depends on the constellation.
Wired options
Not everything needs a radio. Ethernet with Power over Ethernet delivers data and power on one cable and is the most reliable choice for fixed devices such as cameras, access points and building controllers. Industrial fieldbuses (Modbus, PROFINET, EtherCAT) connect machines to controllers and are bridged to IP at a gateway.
A method for choosing
Start with the two constraints that are hardest to change: power source and location.
If the device has mains power and sits inside a building with Wi-Fi, use Wi-Fi unless there will be many devices per access point, in which case use Thread or Zigbee through a hub. If it must run on a battery inside a building, use BLE if a phone is always nearby, otherwise Thread or Zigbee. If it runs on a battery outdoors or across a large site, use LoRaWAN where you can deploy gateways and NB-IoT or LTE-M where you cannot. If it moves or streams, use LTE, 5G or LTE-M depending on data needs. If it is beyond any terrestrial coverage, use satellite.
Then check the remaining axes. Does the device need to receive commands promptly? That rules out the deep-sleeping LPWAN modes. Is there a monthly fee you can pass on? Cellular costs per device per month; LoRaWAN and mesh do not. Does the product need to work in many countries? Regional spectrum rules for ISM bands and operator coverage for NB-IoT vary.
Finally, consider the application layer separately. The radio determines how bytes move; MQTT, CoAP or a LoRaWAN network server determine what those bytes mean to the platform. The MQTT and CoAP guides pick up from here.
Where to go next
- LoRaWAN explained for the most widely deployed private LPWAN.
- Zigbee explained and Thread explained for in-building mesh.
- NB-IoT and LTE-M explained for cellular IoT.
- Bluetooth Low Energy for IoT for phone-paired devices.
Topics: connectivity, wireless, LPWAN, cellular, protocols