Selecting a Suitable Communication method for an IoT project is a crucial part of implementing an IoT system. In IoT, communication methods play a key role, which allows the devices to connect and exchange information. Due to the wide range of applications in IoT and the modern approach to the construction of IoT networks, it is challenging to decide which communication method is suitable for your IoT Project. So, many IoT applications exist and they range from controlling smart homes to industrial automation thus implying that there is no unique communication method that can be adopted.

In this article, we will go through,

• Why are communication methods needed in an IoT project?
• Types of communication methods commonly exist
• Key factors to be considered when selecting the Communication method
• breakdown and use case of each communication method with real-world examples

Why do you need a Communication Method ?

IoT is a network of interrelated devices that connect and exchange data with other IoT devices and the cloud.  IoT devices are typically embedded with sensors and software and can include mechanical and digital machines and consumer objects.

In simple terms, IoT is about connecting a device to the internet and to other devices to make intelligent decisions by processing the data collected by the devices connected to it.

The IoT devices talk to each other or the rest of the network using communication protocols which is a medium to transfer the data and commands within the master device to the slave, sensors, or the cloud server.

When selecting we can examine the characteristics of data transmission such as the maximum range, the power, and the security of the transmission.

We can select a suitable communication method by considering the above-mentioned characteristics. For example, if we want to transmit data nearby, we can use Bluetooth whereas if the distance is very much high, we can use LoRa.

Types of IoT Communication Methods

IoT communication methods can be broadly categorized based on their range and data requirements. We will discuss shortly before getting to know how to select a suitable Communication protocol.

• Wireless Protocol:
  • Short-Range Protocols: Wi-Fi, Bluetooth Smart or Bluetooth Low Energy, Zigbee, and. They are suitable for use in areas that are small in that they can work within the confines of a smart home, wearables, and personal gadgets.
  • Long-Range Protocols: There are LoRa, Cellular (4G, LTE, NB-IoT), and Ultra-Wideband (UWB) under this classification. These protocols are suitable in areas that need to have a large coverage like tracking of assets, smart city, and farming.
• Wired Protocols: Even if wireless communication is the most commonly used in IoT, wired protocols such as Modbus RTU, Universal Asynchronous Receiver-Transmitter (UART), and I2C are used in industries where reliability and security are crucial. Moreover, most of the sensor actuators get connected through this protocol.
• Application Layer Protocols: Some of the protocols that exist in this layer include TCP/ IP and CoAP which deal with the format in which the information data is transmitted and received in the IoT network. These are useful where some data communications in resource-poor settings (limited power/low memory/in harsh environments) are faster and more reliable.

With the above, we look into some divisions of communication methods and such things. Now, we will get into the Key considerations to be considered while selecting a communication protocol for an IoT project.

Key factors to be considered

In choosing the communication protocol for your IoT project the following aspects should be put into consideration. Here are the most important considerations

1. Range and Coverage

• LoRa or Cellular Transmissions like Long-range protocols are appropriate for communicating over long distances for large-scale projects like smart farming or asset tracking. Moreover, Lora-WAN is now rarely using extremely beneficial communication based on LoRa.
• Bluetooth Low Energy (BLE), Zigbee, and Wi-Fi are short-range protocols more suitable for home automation or wearable devices as the communication range is short.

2. Power Consumption

• Minimizing power usage is important, especially for battery-operated gadgets. These protocols include LoRa, BLE, Zigbee, and so on for IoT mainly to reduce their power consumption and thus the battery lifetime should be long since the IoT devices need to work for long durations before battery recharge.
• Closely related to battery utilization, High power consumption protocols like Wi-Fi and Cellular might be used in cases where devices are charged from wall outlets, Smart appliances, or industrial IoT.

3. Data Rate

• Bandwidth is required in applications that require sending large volumes of data such as video or actual sensor data in real time. It is for these uses that Wi-Fi and Cellular networks are a perfect fit.
• The sample data amount is enough for those applications that require only a limited number of bytes, like environmental control, smart metering, and others using LoRa, Zigbee, and NB-IoT networks.

4. Network Reliability

• Network reliability can be described as the compatibility of a particular communication network to provide a steady and uninterrupted service even in harsh environments. This is particularly important within IoT applications since a lack of signal connectivity may cause the loss of data, operations, or safety concerns.
• In the context of industrial IoT where the sensors constantly observe the mechanical structures a dependable conveyance path guarantees that significant information is delivered unceasingly. Supplies like cellular (for instance, LTE) and wired links (for instance, Modbus RTU) are trendy concerning arrangements where high reliability is a priority because they are much less prone to interference than certain sorts of wireless links like Wi-Fi.

5. Cost of Implementation

• The cost tied up in the adoption of a particular IoT communication method comprises physical instrumentation costs such as sensors, gateways, and modules, the infrastructural costs including network establishment and data servers, plus the operational costs such as data tariff, and frequent service charges for hardware maintenance. This cost varies depending on the chosen technology.
• In rural areas, the implementation of LoRa and Sigfox promises to be relatively cheap. This implies that these technologies are cheaper since they do not need much infrastructure to be established; the likes of smart farming or environmental monitoring that is hard to do through normal cellular technology.

6. Regulatory Compliance

• Another requirement of wireless networks is that of following laws governing the utilization of particular frequencies and communications equipment on regional, national, and global levels. Some of the frequencies may be prohibited or require a license in some areas, meaning that the IoT communication approaches are affected.
• LoRa uses unlicensed ISM bands (for example, in Sri Lanka 433MHz and 868MHz in Europe, and 915MHz in North America) and although it may be freely used, it is restricted in terms of power and time usage. Cellular networks on the other hand, run in the licensed bands where authorities such as the FCC in the United States, or Ofcom in the United Kingdom set some frequencies that may be used Compliance with these legal requirements is very important so that the network is not in violation of the law.

7. Latency

• In applications where real-time exchanges of data are needed, they always involve Low Latency e.g. industrial automation or remote-control systems. Rules such as Wi-Fi, BLE, and UWB are frequently applied to these sorts of applications.
• Low latency is less of a requirement in those cases where the frequency of data transmission is not extremely high, say in emissions monitoring where LoRa or Zigbee might do better.

8. Environmental Considerations

• There could be so many environmental constraints which include range, interference, and physical barriers that affect IoT communication protocols. Thus, the appropriate protocol to be used depends on whether the deployment is indoor or outdoor, deployed in urban or rural areas, and whether there are barriers or interference sources within the deployment area.
• Example:
  • LoRa and Sigfox: They can be applied in outdoor, rural, or remote areas thanks to their long-distance operation (up to a few km) and power-saving options. They are used in cases such as wildlife tracking or in smart agriculture, where devices are required to send information over vast areas with few base stations.
• BLE and Wi-Fi: Mainly, these are appropriate when devices are closely situated indoors, where ubiquity is not likely to be a problem. BLE is mostly used in wearables, where interference is close to zero and power conservation is paramount. Wireless is preferably applied in smart homes and offices where more data rates are required and power is not imperative.

9. Network Topology

• Permanent, point-to-point, or point-to-multipoint structures that are typical for UART and Cellular protocols are good for simple structures.
• Some of the mesh networks include Zigbee and some of the BLE implementations. These are more of a hierarchy and allow devices to forward messages across the network structure as seen in smart city applications. LoRa WAN is an example of connecting a huge number of devices to the network through a relevant gateway whereas it’s used in industry-level applications.

10. Security

• The high-security protocols are relevant for applications that require the protection of sensitive data, for instance, IoT devices in the healthcare sector or handling financial operations. Some of the standard protocol securities are MQTT with TLS, Cellular, and Wi-Fi with WPA3.
• Lighter protocols may be suitable for use in contexts where security risks are not extremely high or where extra security measures are employed on the application layer.

11. Scalability

• Flexible processes are useful in projects that might grow in the future. Some of the examples are LoRa WAN and Cellular which have the capability to connect numerous devices spread across an extensive geography, which will be ideal for expanding IoT applications.
• UART or I2C, for example, are not as scalable as SPI, and they could be implemented in places where the number of devices and connections is not going to change much.

12.  Ease of Integration

• Sustainability in terms of compatibility with already existing structures or other systems is another factor. For example, Wi-Fi does not pose compatibility issues with the home or office LAN, whereas RTU-based protocols such as Modbus RTU are best used in industries where ancient infrastructure is employed.
• Frameworks such as ESPNow or ESP SmartConfig may be selected for particular microcontroller-based initiatives where low complicated device connection or communication is indispensable.

Breakdown and use case of each communication method 

• Wi-Fi: Wi-Fi is a fixed Wireless Local Area Network that enables devices within a certain radius (usually up to 100 meters for indoor use) to access the internet or other local networks. For example, we say, Smart Home Systems. Wi-Fi is used in Smart home products like Smart thermostats such as Nest Thermostat & Smart Security cameras like Ring cameras. It incorporates Wi-Fi to access the home network and relays data in real-time and remote control by smartphones.

• UART (Universal Asynchronous Receiver-Transmitter): UART is one of many serial communication protocols that is employed to directly connect two devices. It is often used in embedded systems where slow speed and short-range data communication are required. We commonly use Microcontroller Interfacing. UART Interfacing can again be used to connect a microcontroller, say Arduino with the peripheral devices such as the GPS module or Bluetooth module required for it to communicate directly with this.

• I2C (Inter-Integrated Circuit): I2C is a two-wire serial communication technique for interfacing several integrated circuits, also referred to as ‘ICs’ in a single board. It can adapt multiple devices on the same bus and is widely used for data exchange between the sensors. An example of an IoT system is the use of Linear I2C Sensors in environmental monitoring to give details such as the temperature and humidity by sending it to a microcontroller like Raspberry Pi through I2C BUS.

• MQTT (Message Queuing Telemetry Transport): This simple messaging protocol is suitable for small sensors and mobile devices and is most optimized for low bandwidths and high latencies. It works on the publisher/subscriber system which is quite suitable for IoT. In Industrial Automation, MQTT is employed in the industrial sector to collect data from sensors in industrial plants and forward the data and information collected to a server for processing. For instance, a factory might monitor in real-time the temperature and pressure of the equipment using MQTT.

• LoRa: LoRa is known as a low power wide area networking protocol which is having the capability of supporting long-range communication for more than 10 km depending on the environment of rural areas. It is applied in LoRaWAN networks and suits well when used in battery-supported devices. In Smart Agriculture, LoRa requires sensors that track the moisture and temperature of the soil and many others in big fields.

• UWB (Ultra-Wideband): UWB is a wireless communication that offers highly accurate characteristics in the short-range position location. It has to cover a broad spectrum of frequencies, to be able to transmit data at a very low power. Indoor Positioning is employed in smart buildings for the indoor positioning system or indoor navigation to find an object or a person within a building.

• BLE (Bluetooth Low Energy): Ultra-wideband low-energy (ULE) also known as Bluetooth low energy (BLE) is a wireless personal area network technology reserved for short-range communication. BLE is utilized in wearable fitness trackers such as Fitbit, to measure the health parameters of the clients such as heart rate, and beam this information back to smartphones for real-time tracking.

• Modbus RTU: Modbus RTU is a master-slave version of the serial communication protocol often deployed in the industrial setup. It is intended to be used for data transfer between devices and electronics in particularly noisy conditions most of the time. Modbus RTU is deployed in Slave PLC devices for controlling manufacturing line machinery’s operations. For instance, it may be utilized in controlling the movement of conveyors or their operation and relay the same back to a supervisory system.

• Zigbee: Zigbee is a physical and data link layer for wireless mesh networking technology designed for low-power, low-data rate applications. In Smart Home Automation, Zigbee is applied in smart home automation where many bulbs or switches work in one system and socialize to permit functions such as remote controls or timers that turn on or off automatically.

• ESPNow and ESP SmartConfig: ESPNow and ESP SmartConfig is a protocol created by Espressif for use in the wireless LV, peer-to-peer communication between the ESP8266 and ESP32 microcontrollers without even entering the details of the Wi-Fi in the module itself. These can be used in home automation to build systems of remote control like lights or appliances, where ESP8266/ESP32 devices directly talk to each other without any need for a Wi-Fi network.

Conclusion

These communication methods range from high power consumption to low power consumption, from low data rate to high data rate according to the application requirements. It’s therefore important for one to understand the type of method being used or intended for use in the specific project for it helps understand its strengths as well the weaknesses to avoid before making a decision.