IoT connectivity landscape

IoT connectivity technologies define the connection between a physical device, for example a sensor, and a second point in the IoT system, be it another IoT sensor, a gateway, or an IoT cloud platform.

The connectivity technologies usually differ in their power consumption, bandwidth capabilities and latency characteristics. In this article, we will give an overview of the IoT connectivity landscape and provide some examples of typical use cases for each technology.

If you are in a rush, jump directly to our summary table at the end of this article.

NFC: description

NFC, or Near-Field-Communication, is a communication protocol used to exchange information between two electronic devices at very short distances. It is part of the RFID protocols. NFC uses electromagnetic induction between two antennas to exchange data over the air. It operates on an unlicensed radio frequency band.

Technical details

• Max data throughput rates 424 kbit/s

• Maximal transmission distance <1m

• 13,56 MHz radio band

Typical use cases

NFC has become widely popular for mobile payment applications. It is what you use when you pay at the restaurant with your mobile phone.

RFID: description

RFID stands for Radio-frequency identification. It uses electromagnetic fields to communicate between a tag and a reader device. The tag is usually a passive device that transmits its data, typically an identification number, when the reader sends an electromagnetic interrogation pulse. Hence, passive RFID tags collect energy from the reader's message to transmit their own data. Active tags are powered by a battery and communicate up to a range of 100m.

Technical details

• Different data rate, typically more than 2 kBytes

• Maximal transmission distance 10m (passive)

• Several radio bands, including LF 150kHz and HF 13.56MHz

Typical use cases

Common RFID use cases include access control and asset tracking. Tags can be attached to clothes, consumer packaged goods, pharmaceuticals and even animals.

Zigbee: description

Zigbee is built on top of the IEEE 802.15.4 radio specification. Thanks to its low power, low data rate protocol, it became popular for monitoring applications in the smart home space as it supports mesh topology. It is typically used to transmit low amounts of data over short-range distances. The mesh topology allows extending the range by transmitting a packet through several nodes.

Technical details

• Max data throughput rates 250 kbit/s

• Maximal transmission distance 100m

• 2.4GHz radio band

Typical use cases

Zigbee is used mainly for home and building automation, but also for industrial control, security and smart metering.

IKEA smart lighting products use the ZigBee Light Link, specified by the ZigBee Alliance. Another popular example is the Philips Hue lighting solution.

Thread: description

Thread, just like Zigbee, is based on the IEEE 802.15.4 specification. It is derived from 6LoWPAN, or IPv6, as a mesh networking protocol to control a variety of home appliances. The IPv6 base enables a natural connection between Thread networks and existing IPv6-based networks like Wi-Fi.

Technical details

• Max data throughput rates 250 kbit/s

• Maximal transmission distance 100m

• 2.4GHz radio band

• Maximum number of nodes in the mesh network 250

Typical use cases

Thread is popular in the connected home and building landscapes. The Google Nest product line uses Thread among its supported protocols.

Z-wave: description

Z-wave is again a popular mesh network that started out as a protocol for controlling lighting systems and evolved towards the whole smart home field. It operates at 918/860MHz, a lower frequency range than ZigBee or Thread. Z-wave transmissions are considered extremely reliable as they do not suffer from any interference from the crowded 2.4 GHz band.

Technical details

• Max data throughput rates 100 kbit/s

• Maximal transmission distance 30m

• 908/915 MHz band in the U.S. and 868 MHz in Europe

• Maximum number of nodes in the mesh network 232

Typical use cases

Smart home use cases are the main focus of Z-wave. The Logitech Home Harmony Hub Extender supports Z-wave.

Bluetooth: description

Bluetooth technology is a widely adopted wireless solution used in countless applications that require a high communication data rate, with devices being separated by a few meters. There are two main versions of the protocol, namely Bluetooth Classic and Bluetooth Low Energy (BLE). The original Bluetooth Classic is widely used in streaming applications; think about your car audio streaming. BLE adoption has skyrocketed in the last years as its very low power consumption makes it very popular in many Personal Area Network applications. BLE supports as well point-to-point, star and mesh topologies. It is suitable for IoT applications, as it works with periodic transfers of data and therefore also reduces the amount of battery usage significantly.

Technical details

• Max data throughput rates 1-3 Mbit/s depending on the version

• Maximal transmission distance 100m

• Operates in the 2.4 GHz band

Typical use cases

You will find Bluetooth in many applications where the devices require continuous streaming of data and are in close proximity to each other: headsets, heart rate sports watches, bicycle speedometers, and smart tags. BLE applications are widely seen in smart buildings. Various sensor- and luminaire manufacturers are using BLE in use cases such as occupancy management, room climate monitoring and indoor asset tracking.

WiFi: description

Everyone knows the WiFi protocol for its primary use of connecting homes to the internet. In the IoT space, WiFi is well suited for devices that need to transmit large amounts of data where power consumption is not a concern. It is therefore ideal in confined spaces in buildings, but a poor choice for battery-powered devices.

Technical details

• Max data throughput rates 1 Gbit/s

• Operates in the 2.4 and 5 GHz ISM Bands

• Maximal transmission distance 100m (can be extended with a dedicated device)

Typical use cases

In the IoT spectrum, Wi-Fi is quite popular in video streaming applications. The Canary camera is an example in the B2C sector.

5G: description

5G is the fifth generation of cellular network technology. It is designed to communicate data at a higher speed than the previous generations with increased reliability. This new generation of cellular technology is currently being rolled out around the globe and generates large expectations in the IoT world. With its low latency and enhanced reliability, 5G could support mission-critical use cases in industrial environments.

Technical details

• Max data throughput rates 10 Gb/s

• Frequency range 1 is from 450 MHz to 6 GHz

• Frequency range 2 is from 24.25 GHz to 52.6 GHz

• Maximal transmission distance is around 450m

Typical use cases

The 5G network is not mature yet but shows potential applications in the Industrial IoT (IIoT) area or “smart factory”.

LoRa: description

Introduced by Semtech, LoRa, short form for Long Range, is a radio connectivity protocol developed especially for communications that require long-range and low power. Lora’s spread spectrum modulation and LoRaWAN’s (Low-Power, Wide-Area Network) star-shaped network architecture lay the groundwork for significant range and power-saving capabilities. Its range capabilities broke records in 2017 when a LoRaWAN packet was received over 702 km. This makes LoRa an attractive solution for many IoT- and M2M-enabled projects. It is an open specification which means that companies, cities and private individuals can set up their own LoRaWAN network. The Things Network community pushed the adoption of technology in the hobbyist space. Loriot is a popular network provider in the enterprise field.

Technical details

• Max data throughput rates 250 b/s to 11 kb/s

• Frequency 433 MHz, 868 MHz (Europe), 915 MHz (Australia and North America), 865 MHz to 867 MHz (India) and 923 MHz (Asia)

• Maximal transmission distance 5 km (urban), 20 km (rural)

Typical use cases

LoRaWAN is ideal for sensors that only seldom send a small amount of data, for example, an indoor air quality sensor sending its measurements every 15 minutes. It makes it well suited for smart city cases, energy metering or facility management. Utility companies, as main actors of digitization in our cities, are early adopters of the technology. Allgäuer Überlandwerk in Bavaria is an example of a utility company that sees LoRaWAN technology as an opportunity to optimize operations and resource management.

Sigfox: description

Sigfox is a proprietary network and radio communication protocol. Just like LoRaWAN, it is part of the Low Power Wide Area Network (LPWAN) family. It is used for long-range, low speed and low power applications. The use of Sigfox might be interesting where the coverage of the network allows it but the technology also shows some limitations in the numbers of messages that can be transmitted per day (one message every 10 mins (typ. 140 UL, 4 DL). Use cases that are a good fit are usually cases that do not need to have downlink messages to the device.

Technical details

• Max data throughput rates 100 b/s

• Frequency 868 MHz in Europe, 915 MHz in North America, and 433 MHz in Asia

• Max transmission distance 10 km (urban), 40 km (rural)

Typical use cases

Similar cases as LoRaWAN can be supported by Sigfox. The network coverage might here be a deciding factor, as well as the fact that Sigfox is usually used for uplink only messaging. Typically, remote meter readings (water, electricity) are good use cases. Another example is the case from Amber Loglay, which uses a Sigfox based service on-demand system for freight lifts on construction sites. Thanks to the service on demand Sigfox button, there is not one attendant for each lift but one person operating several. The button solution serves to call the lift attendant to the respective lift when someone needs it.

NB-IoT: description

NB-IoT stands for narrowband IoT. It is part of the cellular IoT technologies with LTE-M. NB-IoT can piggyback on the same mobile network as smartphones. It does it via unused GSM channels, or free space between LTE channels. It requires proper infrastructure and coverage, the use of SIM cards and a subscription to a network provider, just like for your smartphone. IoT cases that require frequent communications are a good fit for NB-IoT, which has no duty cycle limitations.

Technical details

• Max data throughput rates 200 kbps

• Frequency Licensed GSM & LTE frequency bands

• Max transmission distance 1 km (urban), 10 km (rural)

Typical use cases

NB-IoT is used in various applications such as smart agriculture, energy metering, facility management or smart city. The Swiss company Live Track developed for example a smart waste management system that allows the planning and optimization of disposal tours. During a test period of 16 weeks, they were able to reduce the total distance traveled by waste collection vehicles from over 800 km to approximately 540 km (over 30% decrease) with an estimated cost reduction of approximately 30%.

LTE-M: description

LTE-M, which stands for “Long Term Evolution for Machines,” is another cellular IoT technology. Not to be confused with LTE, the 4th generation of mobile network, LTE-M (LTE Cat M1) is an extension of the LTE network for IoT applications. One of the main advantages of LTE-M over NB-IoT is its voice over the network support. It is able to transmit at higher data rates but uses more bandwidth and is a bit more costly.

Technical details

• Max data throughput rates 1 Mbit/s

• Frequency Licensed LTE frequency bands

• Max transmission distance 1 km (urban), 10 km (rural)

Typical use cases

LTE-M is interesting for “mission-critical” applications such as self-driving cars or alerting systems in smart cities. In life-saving medical applications such as for AED-defibrillators, LTE-M is used to send a notification message to the medical authorities as soon as the device is used.

Connectivity technologies overview table

If you are interested in comparing further these connectivity technologies, consider the following references: Sciencedirect, Polymorph, Bluetooth.