While use cases for IoT abound and deployments are growing rapidly, the technology landscape can still overwhelm newcomers. This article gives an overview of wireless connectivity protocols and their respective strengths, weaknesses, and recommended fields of application.
The Ever-Expanding IoT
Enterprises and government agencies are leveraging the Internet of Things (IoT) technology to maximize efficiency and reduce operating expenses while improving service delivery to their constituents. IoT is driving advancements across a wide variety of vertical industries by implementing connected solutions, including utilities, connected vehicles, agriculture, healthcare, transportation, and security for businesses and homes. IoT is also driving new opportunities for innovation – solving problems while delivering global economic and environmental change.
The growth in IoT over the past few years and its future market potential are both impressive. The market intelligence firm International Data Corporation (IDC) estimates IoT spending was approximately $742 billion in 2020. Looking forward, IDC’s Internet of Things Spending Guide expects global IoT to achieve a compound annual growth rate (CAGR) of 11.3% over the 2020-2024 forecast period.
Wireless IoT Connectivity Options
The networking technology landscape remains complex and fragmented when it comes to connecting devices, with no one-size-fits-all protocol capable of addressing all IoT use cases. Each connectivity option has trade-offs between power consumption, bandwidth, and range, as the following diagram shows:
Due to the overwhelming variety of options (and an array of acronyms), it can be difficult to select the appropriate wireless connectivity solution to deploy for specific vertical market use cases.
To help make sense of this connectivity conundrum, here is an overview of the top six wireless categories, detailing their unique advantages/disadvantages, power consumption, range, and bandwidth capabilities.
The following three IoT connectivity options transfer data over small distances – usually less than 150 meters between the “thing” that collects the data and the hub or gateway that processes the data or sends it over the internet to another (often cloud) platform for processing.
Although critical in providing high-throughput data transfer in both enterprise and home environments, Wi-Fi has limitations as to coverage, scalability, and power consumption in the IoT space. For consumers, it is mostly used with smart home gadgets, appliances, and security cameras that connect to power outlets and directly to the internet.
Wi-Fi is a good choice for office environments and smart factories where sensors monitoring production efficiency send data frequently but limited to a relatively small physical range. While technically suited for use in smart offices and similar corporate or public spaces, IT departments often do not allow IoT devices on their networks for security reasons.
Like Wi-Fi, Bluetooth technology can send data continuously but works within an even shorter range (usually less than 10 meters). Bluetooth was originally intended for point-to-point or point-to-multipoint data exchange among consumer devices.
Optimized for power consumption, Bluetooth Low-Energy (BLE) was later introduced to small-scale consumer IoT applications, such as fitness and medical wearables, smart home devices, as well as beacons. Often the data is conveniently communicated to and visualized on smartphones.
Mesh Networks (Zigbee, Z-Wave, Thread)
These solutions are deployed using a mesh topology to extend coverage by relaying sensor data over multiple wireless sensor nodes distributed nearby. Powered nodes cooperate in the distribution of data. Zigbee and similar mesh protocols (e.g., Z-Wave, Thread) operate best within a medium physical range (less than 100 meters).
Mesh network connectivity is most commonly used for wireless control and monitoring applications in smart homes or smart building spaces, like connected lighting, HVAC controls, smoke and CO2 detectors, security, and energy management.
Low-Power, Wide-Area Network (LPWAN) is an umbrella term for any network that allows communication over long distances (at least 500 meters of signal range from the gateway device to endpoint) and uses minimal power. They are best suited for use cases that send small and infrequent amounts of data that are not overly time-sensitive, such as smart utility metering, asset tracking, smart agriculture, environmental monitoring, facility management, occupancy detection, and consumables monitoring. LPWAN connectivity breaks down into two categories: unlicensed and licensed frequencies.
Unlicensed LPWAN (LoRaWAN, Sigfox)
Approximately 25 different LPWAN technologies use unlicensed frequencies, yet LoRaWAN and Sigfox have emerged as the clear leaders in this arena.
LoRaWAN is a long-range LPWAN specification developed and maintained by the LoRa Alliance, a non-profit with over 500 global member companies. LoRaWAN architecture utilizes gateways that relay messages between end-devices and a central network server. It can be deployed as a private network or offered as a public network through integrators. Although based on an open standard, LoRa devices from various manufacturers rely on on-chip technology from the US-based company Semtech.
Sigfox, on the other hand, is a single company in France that developed a patented, proprietary technology. Sigfox rolls out and maintains its own network, sometimes through partnerships, and profits directly from subscriptions to the network. Currently, Sigfox is more popular in the EU region than in the US.
Non-cellular unlicensed band technology can serve some organizations better than the following cellular options because they are less expensive. Still, these LPWANs often perform slower and are less reliable than standard licensed cellular technology.
The term “cellular,” by the way, refers to the land areas over which cellular networks are distributed, with each area being served by at least one fixed-location transceiver; these land areas are called “cells.”