The communication technologies used by IoT devices to communicate data with each other are called IoT networks. Some examples of IoT networks are cellular networks such as LTE-M and NB-IoT, WiFi, Bluetooth Low Energy, Sigfox, LoraWAN, Zigbee, RFID and Ethernet. IoT devices are often connected using wireless communication technologies. In some rare cases, you may find IoT devices connected via Ethernet. Although IoT protocols like MQTT, CoAP, AMQP, etc. operate at the application layer of the Internet, these communication technologies apply to the network layer of the Internet architecture. IoT is the backbone of the fourth industrial revolution. Industry 4.0 is nothing more than the Industrial Internet of Things (IIoT).
When designing an IoT application, choosing a network is the first thing that needs to be decided. Selecting an IoT network typically depends on the use case. IoT networks can be classified into four broad classes, as follows.
- Cellular networks like LTE-M, NB-IoT, etc.
- LAN/PAN such as Bluetooth, WiFi, etc.
- LPWAN like LoRaWAN, Sigfox, etc.
- Mesh protocols like RFID, ZigBee, Z-wave, etc.
Classifying IoT networks is useful for selecting them for a specific application. Selection of a specific IoT network may depend on the required coverage area, cost, device environment, density of IoT devices, power consumption, nature of machine-to-machine communication, required network bandwidth, security, etc. will discuss the broad categories of IoT networks along with some popular networks.
Cellular Networks (3G, 4G, 5G, Next Generation 5G) Cellular networks such as 3G, 4G and 5G are already prevalent in the consumer mobile market. Cellular networks have the widest coverage compared to any other wireless technology. However, these networks have high operational costs and high energy consumption. Despite large coverage and wide bandwidth, cellular networks are not always suitable for IoT devices only due to their high cost and large power consumption. For battery-powered IoT devices, cellular networks get a clear no. Still, cellular networks are suitable for some specific use cases that no other communications technology can suit.
For example, autonomous cars, connected healthcare infrastructures, real-time video surveillance, transportation fleet management and time-sensitive industrial automation are not possible without cellular networks. These applications not only require frequent data communication, but the volume of data involved is also very high. Again, IoT devices that communicate in these applications require very distant deployment. Cellular networks are ubiquitous and offer broad bandwidth that makes them viable for such use cases despite the cost and energy disadvantage. Most of these applications require streaming data with a high payload per day. Since cellular networks are capable of delivering a data rate greater than 380 kbps with a bandwidth of 5~20 MHz (3G/4G), neither high payload nor streaming is an issue. A real boost for most of these applications will be the next generation 5G cell phone.
LPWAN
Cellular networks are unsuitable for battery-powered applications as well as machine-to-machine communication. A viable solution for connecting remotely deployed IoT devices is the Low Power Wireless Area Network (LPWAN). There are licensed and unlicensed LPWANs. The licensee includes NB-IoT and LTE-M. Unlicensed ones include Sigfox and LoRaWAN. Although LPWANs allow battery-powered IoT devices to communicate over long distances, only a small amount of data can be communicated with these technologies due to lower bandwidth. LPWAN has several advantages over cellular networks. Like, these networks are cheap and can be integrated into small circuits. Unlike cellular networks, these networks can run on battery power for several years.
Let's discuss some of the common LPWANs.
NB-IoT
NB-IoT is a licensed LPWAN that allows you to communicate unlimited payload per day at a bandwidth of 180 MHz. This narrowband IoT protocol is low cost and has medium power consumption. NB-IoT devices do not require any gateway and can communicate data directly to the server. With a data rate of 200kbps and unlimited payload per day, NB-IoT allows for a large number of connections. Although the protocol does not offer greater mobility support, it is known for good performance in both outdoor and indoor environments.
LTE-M
LTE-M is a licensed LPWAN based on the use of LTE bases for communication between IoT devices. Also known as Cat-M1, LTE-M provides greater bandwidth, enabling the operation of massive connection density and even applications such as VoIP. Compared to NB-IoT, LTE-M devices have higher power consumption. power and require a gateway to communicate with the server. The devices are also more expensive compared to NB-IoT devices.
LoRaWAN
Maintained by LoRa-Alliance, LoRaWAN offers a coverage area of 15 km. This unlicensed LPWAN has a bandwidth of 125 ~ 500 KHz and a data rate of up to 27 kbps. Operates in a free ISM frequency band. Due to lower power consumption, LoRa is best suited for battery-powered industrial IoT devices. LoRa devices can run on battery power for up to 10 years. Because they are not licensed, LoRa networks have a limitation. They can only use 1% of your bandwidth. Typically, LoRa allows up to 140 12-byte messages to be transmitted uplink per day. There is more flexibility regarding downlinks. Data is always transmitted in 12-byte packets. LoRa is best suited for battery-powered sensor networks where the controller spends most of its time in sleep mode and transmits sensor data intermittently. Data needs to be communicated to a gateway before being transmitted to the server.
Sigfox
Maintained by Sigfox, a global communications services provider, Sigfox is an unlicensed LPWAN. With a bandwidth of 200 kHz, it is an Ultra Narrow Band (UNB) technology. It is based on the same ISM frequency band as LoRaWAN. Allows coverage of 30~50 km. Sigfox allows up to 140 12-byte messages to be transmitted uplink per day. The downlink is limited to 4 messages per day. Despite a lower data rate and narrow bandwidth, Sigfox has the advantage of global reach.
LAN/PAN
The coverage area of local area networks (LAN) and personal area networks (PAN) is limited to the local environment, such as within a building or small facility. Bluetooth/BLE and WiFi are the two most prominent wireless LAN technologies. Despite the small coverage, these technologies offer high bandwidth and excellent data transfer rates.
Let's discuss Bluetooth and WLAN.
Bluetooth/Bluetooth Low Energy
Bluetooth and Bluetooth Low Energy are short-range communication technologies. BLE was designed for consumer IoT applications. It can be used for point-to-point and point-to-multipoint data communication. It is mainly used by smartwatches and smart home devices to communicate with cell phones or smart hubs. The new Bluetooth Mesh specification has increased the scalability of BLE networks. With low power and low power consumption, Bluetooth beacon networks can be used in retail stores for consumer services such as in-store navigation, personalization and content delivery.
WiFi
WiFi networks offer high bandwidth and excellent data transfer rates, but at the cost of high power consumption and limited coverage. Due to limited coverage, high power consumption, and lack of scalability, WiFi networks are never used in industrial IoT applications. Because WiFi networks are primarily available as broadband services for homes, they are useful for smart home and home security applications. The newest generation of WiFi – WiFi 6.0 is applicable to retail applications and open WiFi infrastructures serving digital mobile services.
Mesh Protocols
Mesh protocols are best suited for low-range distributed networks, such as sensor networks and low-range industrial IoT. Data is communicated to a central gateway or hub. These communication technologies are robust solutions for building applications.
Let's discuss some of the mesh protocols/technologies.
Zigbee
Zigbee is a popular unlicensed mesh protocol widely used in distributed IoT applications. This is a short-range protocol that covers a distance of less than 100 meters. In industrial applications, it is directly compared with LPWANs. Compared to LPWAN, Zigbee offers higher data transfer rate and greater energy efficiency. If short range is not an issue, Zigbee devices can run for years without battery replacement. Because Zigbee devices operate in a mesh topology, the network remains operational by routing communication through other devices, even if a device within the network is turned off or malfunctions. Along with WiFi, Zigbee is also widely used for home automation.
Z wave
Z-wave is also a mesh protocol like Zigbee. It has greater coverage and was designed to serve applications such as smart homes and home surveillance. Z-wave uses low-frequency radio waves that are not interfered with by WiFi signals. Compared to Zigbee, Z-wave is a proprietary technology and requires a license to use. One issue with Z-wave devices is interoperability. The Z wave operates in different frequency bands in Europe and the USA.
RFID
RFID is mainly used for asset tracking. RFID tags communicate minimal data over a short range, usually for identification. To read RFID tags, line of sight is not required, as is the case with barcodes. This technology is widely used in the retail and logistics sector. Some popular applications of RFID include supply chain management, asset tracking, electronic passport, automated checkouts, human implants, medical monitoring, security access control, and payment systems. In India, FASTag, a passive RFID technology, is used to automate toll payments.
Conclusion
There are several different IoT networks. These communication technologies can be broadly classified into cellular networks, LPWAN, LAN/PAN, and Mesh technologies. The classification is mainly based on coverage and bandwidth. Most IoT networks are wireless communication technologies. Each class of IoT network has its pros and cons. After selecting a suitable category, IoT developers can make a selection of specific networks based on cost, device environment, security, device density, data bandwidth, data transfer rate, data frequency, quality service, network architecture, and management.
