Sergey Nivens - Fotolia
The type of IoT connectivity an organization uses is critical to the success or failure of a new IoT project. Considerations such as the length of battery life, network coverage and cost all come into play when an organization needs a connectivity mechanism.
Since Kevin Ashton invented the concept of the internet of things in 1999, the number of IoT devices available has grown from zero to around 27 billion. Today, connectivity options include proprietary and cellular wireless transceivers that broadcast data to IoT devices a few feet or a few miles away and satellites that transmit data from orbit.
Organizations have significantly more technologies available to connect an IoT device to the internet or the cloud, including Ethernet, Wi-Fi, low-power WAN (LPWAN), cellular options and satellites. Each option has advantages and disadvantages that organizations must understand to meet their needs.
Ethernet offers a fixed connection
Ethernet connections were among the first methods organizations used to link an IoT device to a network. They remain a suitable choice if a device is heavy and doesn't need to move from a fixed position. Power over Ethernet, a technology that carries electrical currents through data cables instead of power cords, can also minimize the amount of cabling used in a wired deployment.
Wi-Fi works best for offices and buildings
IoT devices, such as sensors, security cameras, and home and enterprise IoT units use Wi-Fi as a connection mechanism.
Wi-Fi is one of the most popular wireless connectivity options worldwide. The unlicensed spectrum at 2.4 GHz and 5 GHz offers real-world ranges that top out at around 410 feet from the access point. Connections of 2.4 GHz can support data rates of 150 Mbps and can better penetrate walls and other solid objects. Organizations would use 2.4 GHz for IoT devices in offices or other buildings. Links of 5 GHz can support data rates of around 1 Gbps. Unless the organization boosts the signal on the 5 GHz band, the range of the Wi-Fi signal drops by about half.
The average Wi-Fi battery life for 2.4 GHz or 5 GHz bands lasts for eight or nine hours. That battery lifespan works for office computers and phones, but not for sensors and IoT devices that require weeks, months or even years of battery.
LPWAN can support thousands of sensors
Low-power WAN IoT standards are specifically designed for IoT usage to wirelessly deliver low amounts of data from proprietary base stations to sensors and devices.
Organizations most commonly use the LPWAN technologies LoRa, which is short for long range and championed by chipmaker Semtech, and Sigfox. LoRa and Sigfox both use the unlicensed industrial, scientific and medical bands to support their bidirectional communications, which includes the 868 MHz band in Europe, 915 MHz spectrum in North America and the 433 MHz frequency in Asia.
Both LoRa and Sigfox offer a realistic range of about 10 kilometers (km) in urban deployments and more than double that range in open rural areas with fewer buildings on the skyline.
Sigfox and Semtech each offer gateways to simplify and inexpensively deploy their separate technologies as private networks. In corporate buildings and worksites that support thousands of sensors and other IoT devices, these LPWAN technologies have gained a lot of recognition for use in IoT deployments.
LoRa leads the pack in terms of LPWAN technologies, partly due to a startup called Helium that has introduced a DIY IoT network based on the LoRaWAN technology across North America and Europe.
Cellular adds range to coverage
Narrowband IoT (NB-IoT) is the cellular alternative to the LPWAN technologies. The technology uses licensed 4G LTE spectrum. Unlike Wi-Fi or LPWAN, it doesn't require an Ethernet connection back to the internet, and major carriers across the world have supported its deployment.
NB-IoT has a range of 10 km and offers good coverage, even indoors or underground, such as parking sensors that monitor deep in a garage.
The technology offers data rates of 20 to 100 KBps and supports a battery life of up to 10 years in sensors and other devices. Its cellular sibling LTE-M offers similar range capabilities but supports higher data rates of 1 MBps and lower latency.
The major difference between NB-IoT and LTE-M is that the former doesn't support mobility on a network. NB-IoT better suits static connections, rather than devices that move. While NB-IoT doesn't support voice commands, LTE-M does, making it better suited to applications such as voice-controlled security panels, fleet data sensors or anything that require high data downlink channels.
The 5G standard will incorporate LTE-M and NB-IoT as IoT specifications, most likely in the coming year.
Satellite makes off-the-grid areas accessible
Satellites offer truly ubiquitous coverage for IoT devices, capable of reaching objects with limited or no access to ground-based networks. If an organization needs IoT coverage in the middle of an ocean, then they need a satellite connection. Geostationary satellites that orbit 23,000 miles above earth can already connect IoT devices all over the world. Low earth orbit satellites are also coming into vogue as companies, such as SpaceX, start to launch massive constellations of micro satellites that target the IoT market.