What is M2M ?

M2M (Machine-to-Machine) communications enable devices and machines to communicate and exchange data without human intervention. Various standards and protocols facilitate M2M communication such as MQTT, CoAP, LwM2M, HTTP, DDS, Zigbee and Z-Wave. M2M architecture is designed in such a way that its capabilities can be used for remote monitoring, predictive maintenance, automation, environmental monitoring, asset tracking and more.

M2M System Architecture

Following are the elements of M2M system. Let us understand functions or working of M2M system architecture components.
• Things/Devices : They are equipped with communication capabilities to interact with other components of M2M system. They can range from simple sensors, actuators to complex machines which can collect data or perform specific tasks.
• Connectivity : Devices require connectivity to communicate with each other and exchange data. The communication technologies can be wired and wireless which include cellular networks (2G, 3G, 4G or 5G), wifi, ethernet, zigbee, LoRaWAN or satellite etc.
• Network Infrastructure : It facilitates communication between devices and servers or cloud platforms. It also includes switches, routers (or access points), base stations and other networking equipments that ensure data transmission and routing.
• Gateway : In some M2M systems, gateway is needed as intermediary between devices and servers/cloud. It can perform functions such as data pre-processing, protocol translation or security functions. It also enables devices having different protocols to communicate with each other.
• Cloud platform or central server : It serves as central repository to collect data, process it (if required) and store the same. It may host applications and services for specific actions or analysis. The cloud platform includes databases where data is stored for analysis, reporting and retrieval.
• Analytics and other apps : They help in analyzing the data and to process the data to derive insights and to generate reports. They are also used to trigger actions based on analysis.
• User interface : This can be in the form of mobile apps or web portals. They allow end users or admins to monitor and control devices and to check overall system remotely.

M2M Phases

The generic architecture of M2M can also be categorized into four phases as shown. It consists of collection of the data, transmission of the data through the communication medium/network, assessment of the data collected and response to the machine based on the assessment.

Example :
Let us take example of smart meter to understand the M2M concept. Smart meter records the electricity rate which will be communicated to the software application over some medium using internet. This application process the data sent by the smart meter and decides whether the consumer device can be switched on at this time or at later stage to conserve the energy. Hence smart electricity meter here acts as interface between both consumer as well as for electric company to save the energy and save the money.

M2M system support a mechanism to manage and interact with multiple M2M Applications. The M2M system Architecture consists of following:
•  M2M Applications
•  M2M Transport network, which covers Access network,core network(CN) and M2M service capabilities
The architecture is devided into M2M Device domain, and a Network and applications domain.

M2M Capabilities

Following capabilities of M2M have the potential to revolutionize various industries and applications. Some key M2M capabilities are as follows.
• Remote monitoring
• Data collection and analysis
• Automation of various processes and tasks
• Remote control and management of devices and systems
• Smart grids and energy management to allow real time monitoring and control of energy
• Predictive maintenance
• Asset tracking
• Environmental monitoring
• Healthcare and telemedicine
• Smart home and IoT applications

M2M Applications

The cellular based M2M solutions provide easier installation and provisioning targetted mainly for short term deployments. M2M communication could be carried over mobile networks such as GSM-GPRS, CDMA EVDO networks, 4G LTE etc. In the M2M communication, the role of mobile network is largely confined to serve as a transport network.
M2M devices vary from highly-mobile vehicles communicating in real-time, to im-mobile meter-reading appliances that send small amounts of data at random instants.
It covers the communications between the M2M Gateway(s) and M2M application(s), e.g. xDSL, LTE, WiMAX, and WLAN.

Cellular M2M is widely adopted in energy,transport,real estate and agriculture sectors. As mentioned previously smart meter utilizes the energy efficiently and hence bring down CO2 emissions. Hence M2M helps in lowering the effect of global warming.
In the transport sector, M2M helps by providing information regarding best optimized routes to trucks,ships,trains and planes so that wastage of fuel can be avoided. This also helps reduce CO2 emissions by cutting the distance of the travel.
M2M helps in building and home management by conserving energy for various systems viz. cooling, lighting,heating,ventillation and other electronic appliances. It also provides security for the home or building owner with the M2M compliant security enabled devices.
In agriculture sector, M2M provides solutions to monitor cattle health and grazing style, soil monitoring,smart farming and smart watering. This helps grow large amount of crops with lesser resources and hence save money for the farmers.

M2M Protocols

M2M (Machine-to-Machine) Communication rely on various standards and protocols to ensure interoperability and efficient data exchange between devices and systems. Some of these key standards are described below.
MQTT (Message Queuing Telemetry Transport) : It is public subscribe messaging protocol designed for IoT and M2M applications. it operates on broker based architecture which allows devices to publish messages to central server (i.e. broker) which later distributes those messages to other devices (subscribers) as per their requests.
CoAP (Constrained Application Protocol) : It is designed for M2M communication in constrained environments such as low power devices and networks. it is based on REST architecture.
LwM2M (Lightweight M2M) : It is a protocol developed by Open Mobile Alliance (PMA) for M2M communication in IoT devices. It is used to manage and control devices remotely. It can be used for firmware updates, monitoring and configurations of devices.
HTTP (Hypertext Transfer Protocol) : It is widely used for web communication. It is used when interacting with web based services and APIs.
DDS (Data Distribution Service) : It is a standard for real time data distribution.
AMQP (Advanced Message Queuing Protocol) : It is a messaging protocol that allows reliable message delivery between devices and systems.
Zigbee : Low power wireless standard which works in mesh topology. It is defined in IEEE 802.15.4 standard. It is used in home automation and industrial settings for M2M communication.
Z-wave : It is another wireless communication standard used in smart home automation and other M2M applications.
3GPP : It defines various cellular standards which include GSM, LTE and 5G etc. These standards are often used for M2M communication.
OPC UA : It is machine to machine communication protocol used in industrial automation to enable interoperability and data exchange between different machines and systems.

There are several more M2M standards and protocols which include Modbus, CAN, Thread, Bluetooth, LoRaWAN, Sigfox, AMT, XMPP etc.


Standard -ETSI TS 102 689 Machine to Machine Communications (M2M); M2M service requirements Standard -ETSI TS 102 690 Machine to Machine Communications (M2M); M2M functional architecture
These documents can be downloaded from website https://www.etsi.org/Website/Technologies/M2M.aspx

Conclusion : The M2M communication offer increased efficiency and improved user experiences. M2M protocols offer unique capabilities such as MQTT/CoAP are used for lightweight messaging, LwM2M for remote device management, DDS for real-time data distribution, HTTP for web-based interactions etc. The Zigbee and Z-Wave are used for low power wireless connections.

M2M Related Links

Difference between M2M and IoT

IoT Wireless Technologies

WLAN    THREAD    EnOcean    LoRa    SIGFOX    WHDI   
Zigbee   6LoWPAN   Zigbee RF4CE   Z-Wave   NFC   RFID   INSTEON  

Difference between MQTT and REST, DDS, SMQTT and CoAP protocols

RF and Wireless Terminologies