[Updated in November 2023]
There are many IoT communication protocols out there, and it can be overwhelming to sift through their specifications and determine which technology is right for your application.
Meanwhile, opting for the wrong IoT communication protocol can drain your connected devices of power, cause signal interference and delays in data transfer, open security loopholes, and render the whole setup a failure.
To help your Internet of Things startup avoid this scenario, Expanice has written this article.
Read on to find out:
- What IoT protocols are
- How IoT devices communicate
- What sets wired and wireless IoT protocols apart
- Where the difference between network and data protocols lies
- Which IoT communication technologies currently dominate the market
- And how to select the right IoT connectivity tech stack for your project
IoT Protocol Essentials
Before diving into a detailed IoT protocol comparison, let’s figure out what an IoT protocol is exactly and what role this technology plays in IoT software development.
What Are IoT Communication Protocols?
An IoT protocol is a set of rules that govern how devices in an Internet of Things network communicate with each other.
Just like how we follow certain rules in a language to communicate effectively, devices in an interconnected network use IoT protocols to transmit and receive information in an understandable and organized manner.
Every IoT communication protocol has distinct characteristics, such as range, resource usage, and power consumption, which make it suitable for one project and useless for another and may affect its implementation costs.
For example, Bluetooth, an IoT connectivity technology commonly used in consumer electronics, healthcare IoT, and smart home solutions, doesn’t need much memory and power to operate, but its connection range is limited.
In the context of IoT, protocols play a crucial role in ensuring that data is transmitted efficiently, securely, and reliably between numerous devices that may vary greatly in their capabilities and functions.
By following the same set of rules or protocols, miscellaneous devices can work together harmoniously, sharing data and collaborating to create a smart, interconnected environment.
How Do IoT Devices Communicate with Each Other?
IoT devices communicate through complex networks using different protocols designed for specific tasks and environments.
These communications can be classified into three categories:
- Device-to-device
- Device-to-gateway
- Device-to-cloud or data center
The communication process involves collecting, transmitting, and receiving data, often with a feedback loop for making real-time adjustments.
Step 1: Data Collection
An IoT device collects data via sensors, measuring parameters like temperature, humidity, or light intensity. In edge IoT deployments, initial data processing can occur on the device.
Step 2: Data Transmission
Data, once processed, is transmitted using communication protocols like Wi-Fi, Bluetooth, or Zigbee, to another device, gateway, or central system.
Communication protocols operate at different layers of the IoT architecture. For example, Bluetooth enables communication between devices, while data distribution service (DDS) handles the distribution of data at the application layer. Understanding these layers and protocols is crucial for optimizing and securing IoT communications.
IoT communication protocols operate at different layers of a cyber-physical system
Step 3: Data Reception
The recipient, be it another device or central system, receives and processes the data. It's at this juncture where communication protocols end, and business logic begins.
- Business logic integration. Upon receiving the data, application or business logic is applied to analyze and respond to it. This could involve taking an action, like adjusting a thermostat, based on the temperature data that is received.
- Feedback loops. IoT systems often utilize feedback loops, in which devices constantly communicate and adjust their behaviors based on data analytics and responses. This enables the creation of automated and adaptive systems.
How Do Wired and Wireless IoT Protocols Compare to Each Other?
Wired IoT devices are connected through low-voltage or standard power lines. Every node has a unique ID and embedded software running on it. Such devices are self-sufficient and don’t depend on a central hub. They communicate via special protocols, such as X10 and Insteon.
Thanks to their reliability and real-time data transmission, wired IoT protocols have found a home in industrial automation deployments, security systems, automotive products, smart grids, and building automation solutions.
However, many innovation analysts, such as Sandra Wendelken of IDC, credit wireless IoT connectivity technology for the recent advancements in the Internet of Things field.
Even though wireless IoT solutions do not always offer real-time access to data, they allow for adding more devices to the network on the fly without complex configuration.
The benefits of wireless IoT communication protocols over their wired counterparts include:
- Scalability: standard protocols support adding new devices with minimal effort
- Interoperability: wireless IoT communication protocols can be programmed to work with different hardware, such as chips and gateways, and support devices from various vendors
- Reliability: standard communication technology ensures secure data transmission and robustness against interferences
Speaking of wireless IoT protocols, they can be further segmented into short-range and long-range connectivity technologies.
Let’s see how they stack up against each other.
Short-Range vs. Long-Range Wireless Communication Protocols
- Short-range IoT communication technologies operate over a limited range while keeping connectivity costs and power consumption down. Such protocols present a great option for smart home and commercial building automation. Some popular examples of this technology are Bluetooth and Zigbee protocols.
- Long-range IoT communication protocols cover larger distances. They mostly attempt to reduce throughput to conserve power for long-distance transmissions. Popular applications of this technology are industrial site monitoring solutions, agricultural systems, and smart cities. One example of a long-range protocol is LoRaWAN, which can span over 10 km if no physical obstacles are present.
To select the right IoT communication protocol, you should thoroughly analyze the functional and non-functional requirements of the IoT product you’re working on
IoT Сommunication Protocols Classification
One of the most common approaches is to divide IoT communication protocols into two groups — data and network protocols:
- Data protocols operate at the higher layers, such as application and presentation
- Network protocols work from data link, transport, network, and physical layers
Below you will find a rundown of the most-used data and network IoT protocols.
IoT Communication Technologies: Data Protocols
IoT data protocols connect low-power IoT devices and provide point-to-point communication with the hardware directly in offline mode. The connectivity is achieved through a wired or cellular network.
Advanced Message Queuing Protocol (AMQP)
This application layer protocol allows systems to communicate with each other regardless of the platform being used. It ensures compatibility between clients from different vendors. AMQP guarantees secure and reliable communication, even in cases where the network is weak or one of the systems is temporarily inaccessible. It specifies "forwarding addresses" that messages can be routed to in the event of a connection failure.
This protocol is popular in settings with server-based analytical environments, such as banking technology solutions. Otherwise, its application is rather limited due to its heaviness.
AMQP integrates with the Transport Layer Security (TLS) protocol, which ensures data encryption upon transfer and strengthens IoT security. Additionally, this IoT communication technology implements the Simple Authentication Security Layer (SASL) framework for secure authentication handshake between clients and servers.
Advantages:
- Reliability
- Security
- Support for different messaging patterns (publish-subscribe, store-and-forward, and classic messaging queues)
- Extendability with minimal effort
Disadvantages:
- Heavy memory requirements
- Slow data transmission due to large message size
Message Queuing Telemetry Transport (MQTT)
This lightweight IoT communication protocol ensures a reliable connection and operates on top of TCP/IP networks. MQTT is suitable for wireless systems with constrained bandwidth and high latency, such as mobile devices operating on an unreliable network. That’s why Facebook used it for its online chats. Another application is remote monitoring, as MQTT shines at gathering small messages from devices with limited capacity at remote locations.
Unlike AMQP, this IoT protocol is restricted to publish-subscribe architecture and has three main components — subscriber, publisher, and broker. The subscriber mechanism generates data, the publisher offers routing options, and the broker ensures security.
It doesn’t provide a device management structure or defined data representation. Hence, these parameters are vendor-specific.
Advantages:
- Low power consumption
- Low bandwidth usage
- Ability to function well with unreliable connections
Disadvantages:
- Limited interoperability between devices from different vendors
- Inherent security constraints (relies on short user names and passwords for authentication)
- Poor extendability
- Limited choice of messaging patterns (only publish-subscribe)
Constrained Application Protocol (CoAP)
The Internet Engineering Task Force designed this IoT communication protocol to address the needs of HTTP-based systems.
Even though the internet is free for everyone to use, it’s too heavy for many IoT applications. Therefore, the IoT community tends to dismiss HTTP, considering it unfeasible for IoT applications.
CoAP allows for seamless integration with HTTP, minimizing any additional overhead. It achieves this by supporting short wake-up and long sleep states. It enables HTTP clients to exchange information even with limited resources. The IoT protocol is widely used in building automation and smart energy applications.
CoAP depends on User Datagram Protocol (UDP) packets for communication and message passing. This technology is utilized for machine-to-machine applications and allows devices with limited capacity, like low availability, to join the IoT environment. It can even work with microcontrollers with only 10 KiB of RAM.
Advantages:
- Highly secure as it uses DTSL parameters by default
- Easy to deploy
- Works efficiently with devices that have limited capabilities.
Disadvantages:
- Messages can reach a destination in the wrong order, which is a common issue with UDP
- Difficulties communicating with devices behind Network Address Translation (NAT), which can generate dynamic IP addresses
Data Distribution Service (DDS)
Object Management Group (OMG) developed this IoT communication protocol for real-time systems. DDS offers a reliable and scalable data exchange using a publish-subscribe pattern. Its scalability is attributed to the fact that DDS supports the dynamic discovery of publishers and subscribers. It works well with the cloud and low-footprint devices and provides interoperable data sharing, which is software and hardware-independent.
This protocol is believed to be the first open international middleware IoT standard.
Advantages:
- Scalable
- Highly secure and powerful QoS mechanism
- Guarantees low-latency communication
- Connects devices from different vendors
Disadvantages:
- Heavy on bandwidth (consumes twice as much traffic as MQTT)
- Only interfaces with web services via a gateway
IoT Communication Technologies: Network Protocols
IoT network communication protocols connect medium and high-power IoT devices over a network. This technology typically operates over the internet.
There are three common ways to connect IoT devices: point-to-point, star networks, and mesh topology.
When choosing between a point-to-point, star, and mesh network, you should weigh in on the availability and performance requirements of your product, as well as your development budget
- In point-to-point deployments, two nodes are connected directly, forming a close network. Data on this network doesn’t travel on the public internet, making this connection very secure.
- In a star network, all nodes are connected to a central gateway. The gateway collects and transmits data for further processing and storage. This approach requires less energy because devices can rest between transmissions. However, if a node cannot access the gateway, it is unable to transmit data. Another drawback is that the gateway presents a single point of failure. If it is disconnected, the entire system will cease to function.
- Mesh networks are more reliable, as other nodes can also receive data from their neighbors and pass it further to the gateway. So, a node’s functionality isn’t limited by its ability to access the gateway directly. This type of network can cover larger distances than star networks and heals itself. It automatically recalculates data transmission routes in case of a node failure.
There are several IoT communication protocols you could use to create these types of networks.
Bluetooth and Bluetooth Low Energy (BLE)
Bluetooth is a wireless technology that allows data to be exchanged in small amounts over short distances at a high speed. Its ability to transfer data faster comes at the cost of relatively high power consumption.
In 2010, Bluetooth was optimized for short-range IoT communications. Known as BLE, this version of the connectivity protocol boasts greater energy efficiency. However, their data transfer speed is also slower compared to Bluetooth.
It’s worth mentioning that a BLE-enabled gadget can’t communicate with a classic Bluetooth device unless both of them support both versions of the IoT protocol.
Advantages:
- Low latency
- Lower implementation costs due to hardware simplicity
- Easy internet access via a smartphone
- Data encryption by default
Disadvantages:
- Uses the crowded 2.4 GHz frequency
- Might not be suitable for large files
- A limited number of connected devices
Zigbee
Zigbee is a robust and scalable IoT protocol that is used to gather sensor data in home automation and industrial applications. It transfers small amounts of data over moderate distances. Zigbee operates on a self-healing mesh topology, which makes it highly reliable. New devices can join the network after performing the “handshake” process, which takes merely 30 milliseconds.
This IoT connectivity protocol demands a custom gateway to control connected devices, which is expensive compared to Bluetooth.
Advantages:
- Can accommodate up to 65,000 devices
- Low power consumption (small devices can operate on one battery for several years)
- Relatively long range of communication
Disadvantages:
- Uses the common 2.4 GHz frequency, which is prone to interferences
- Requires a custom gateway, which is expensive
Z-Wave
This is a low-power wireless IoT protocol, which is commonly used for smart home solutions and business applications. Z-Wave offers the lowest latency among network IoT communication protocols presented in this article. A single Z-Wave network can potentially handle a maximum of 232 devices, including the central controller.
It’s important to note that this technology operates at a different frequency in each country, meaning that users must purchase a new device when changing their location.
Z-Wave is a proprietary technology managed by Z-Wave Alliance that oversees certifications. So, every Z-Wave device is compatible with every Z-Wave controller independently of the manufacturer. Also, all the specifications were released to the public back in 2016, making this standard accessible to developers.
Advantages:
- Avoids the crowded 2.4 GHz frequency used by Wi-Fi, Bluetooth, and Zigbee
- Low latency
- Low power consumption
- Reasonable coverage
Disadvantages:
- Low data transfer rate
- Premium prices
Wi-Fi
Wi-Fi uses Internet Protocol (IP) to connect devices on a Local Area Network (LAN). It ensures reliable and secure communication between closely located devices — for instance, gadgets within one smart home deployment. This IoT protocol is relatively cheap and easy to implement. It works well with heavy files and can handle vast amounts of data.
However, this IoT communication protocol is too power-consuming and has inherent coverage limitations.
Advantages:
- Convenient and easy to install
- High data transfer rate
Disadvantages:
- High power consumption
- Lack of scalability
- Short-distance communications
Long-Range Radio Wide Area Network (LoRaWAN)
This is a noncellular wireless wide area network technology that connects devices over a long range, which makes it suitable for smart cities and industrial systems. LoRaWAN can potentially connect millions of IoT devices and is optimized for low power consumption. New devices can be either hard-coded or arranged into an over-the-air connection.
A LoRa gateway gathers data from different sensors and transmits it to a server or the cloud over a standard IP protocol. LoRaWAN offers two security layers — one for the network layer and the other for the application.
This IoT communication protocol is not an option for applications that require low latency or transfer a large amount of data.
Advantages:
- Scalability
- Covers large distances
- Low power consumption
- Operates on unlicensed frequency
Disadvantages:
- Low data transfer rate
- Custom LoRa gateway
- Not suitable for real-time applications
A detailed IoT communication protocols comparison based on their network topology, data transfer capabilities, frequency, power consumption, and cost
How to Select the Right IoT Protocol for Your Project
There is no single IoT communication protocol that will always save the day and work well for every task.
Selecting the right connectivity technology is therefore an important decision for an IoT startup, and it needs to be approached carefully.
When looking for the best option for your next IoT project, consider the following criteria:
- Device capabilities. Some devices support specific communication protocols. So, your hardware choices will restrict IoT protocol options.
- Synchronous response requirements. If the system doesn’t expect an immediate response to actions, you can use asynchronous communication patterns and select from a wide range of MQ protocols, such as MQTT.
- Connectivity. Depending on the connection type and device requirements, you need to consider such factors as data transmission rate, communication range, and latency.
- Power consumption. This is not a problem if you can afford to plug your devices into power sockets, like with stationary home automation products. But if your devices run on batteries and can’t be recharged, then a low-power protocol would be a better alternative.
- Allocated budget. IoT communication protocols vary significantly in their associated costs. Some protocols offer low installation expenses, allowing an ordinary smartphone to serve as a gateway. In contrast, others entail substantial upfront fees to join the respective alliance, in addition to ongoing charges for each connected device. Furthermore, the expense of integrating custom gateways into your IoT deployment should not be overlooked. To learn how much you could pay for custom IoT product development, check our IoT cost article. Additionally, you can use our software development cost calculator to better plan our development budget.
Data transfer rates, coverage, and power consumption are among the key criteria for selecting a suitable IoT connectivity tech stack for your IoT project
How Expanice Approaches IoT Protocol Selection
To shed light on our IoT protocol selection process, we’d like to walk you through several projects from the Expanice portfolio and explain why we opted for a particular connectivity tech stack in each case.
Cryo Chamber Management for Hospitals and Spa Salons
Initially, the customer approached us asking to build a simple mobile app that would allow users to register and pay for cryo sauna services.
The scope of the project kept expanding, and after incorporating IoT hardware and software, the cryo chamber management system became fully automated. Our team fitted the sauna with different sensors to monitor oxygen levels, patients’ heart rate, temperature, etc., and a built-in safety control that would manage the chamber and make adjustments when needed.
The mobile app, besides registration and seamless payments, would permit users to connect with their EHR systems and medical records. The facility’s staff could rely on our software to access customers’ data, draft agreements, customize prices, conduct surveys, and perform other administrative tasks. They could also view the data coming from the chamber and make adjustments remotely.
As a result, energy and liquid nitrogen consumption became 17% lower compared to the competitors’ products.
IoT protocols used:
- HTTP to support communication between the receptionist’s tablet and the back end
- RabbitMQ for asynchronous communication with back-end services when no immediate response is expected and processing can be queued
- Modbus to facilitate communication between the tablet and the chamber’s sensors
Smart Curtains Control System
The client approached Expanice to develop back-end software for controlling IoT-powered smart curtains. After incorporating an increasing number of features, this project evolved into a comprehensive IoT solution. This solution encompasses an optimized cloud infrastructure hosted on AWS and a remote-control mobile application, in addition to the previously mentioned back-end components.
The system can manipulate smart curtains based on different patterns. For example, it can open and close the curtains at sunrise and sunset times considering the date and the house’s location. Or it can tie these actions to an alarm clock. The mobile app gives users the possibility to control their curtains remotely and open/close them at any time.
When the system was initially deployed, only a couple hundred devices were connected. The solution scales automatically as more devices are added without the need for expert interventions. Our team also managed to optimize AWS usage and save 66% on cloud-related costs.
IoT protocols used:
- HTTP to support communication between the mobile app and the back end
- MQTT for asynchronous communication with IoT hardware via AWS core services
Our Algorithm for IoT Protocol Selection
When selecting IoT protocols for these projects, we analyzed the hardware capabilities and product features and assessed the budget allocated for device purchase and software development.
Next, we shortlisted viable IoT communication protocols, considering the following factors:
- The feature set of the IoT products and the protocols that would support the desired functionality
- Our customers’ hardware requirements and budget limitations
For the list of protocols that satisfied these criteria, we prioritized the connectivity technologies by their price and functionality.
Our eventual choice was the protocols that scored higher on the priority list and were the easiest to integrate with the rest of the system.
Here’s another example that could help you choose the appropriate IoT communication technologies for your project.
A typical IoT solution contains the following components:
- Hardware
- A mobile application that allows users to control the hardware
- An admin program (back end) to view dashboards and manage the platform
Such a product will follow definite communication patterns:
- Mobile app -> hardware
- Mobile app -> back end
- Hardware -> back end
- Browser used by the admin -> back end
To choose IoT protocols that best meet your hardware requirements, answer the following questions:
- Are there any limitations on power consumption?
- Are there any requirements regarding local device connection?
- Do you need to integrate other hardware pieces, such as sensors?
- Can the system operate with asynchronous communication?
By answering these questions, you’ll be able to shortlist viable connectivity options and select an optimum tech stack together with your IoT development partner.
To Sum Up
Every IoT communication protocol has a set of parameters that make it a success in one application and utterly useless in another.
For example, Bluetooth is a cheap and reliable option for home automation systems, where devices are located within a short distance from one another. Meanwhile, LoRaWAN is the go-to protocol for industrial applications as its range spans up to 15 kilometers, all with minimal power consumption.
Also, you might end up using several IoT protocols for one project, with each connectivity technology being responsible for a specific task. For instance, Wi-Fi can handle large file transmission while Z-Wave can ensure interference-free communication, as it avoids the 2.4 GHz frequency band.
If you’re considering an IoT project but have doubts about which communication protocols are best suited for your needs, just contact us! Expanice can help you with the technology selection and deployment.
