M2M/IoT Gateways

Many M2M and IoT solutions rely on gateways. A gateway is a specialized computer that is typically deployed on or close to an asset (at least in our Enterprise IoT context). Gateways provide connectivity to different devices, to the Internet, or to enterprise networks. In addition, gateways usually run local logic, from simple routing logic and more complex data collection and filtering to highly complex automation, analytics, and application logic, depending on the solution.

Working with an M2M/IoT gateway-centric architecture has many advantages:

• Multiple, heterogeneous devices can be more easily integrated by utilizing gateways for protocol mappings and local connectivity
• Gateways enable more semantically rich applications by providing abstractions
• Execution of local business logic enables real-time behavior and helps to reduce response times
• Gateways help to implement a level of autonomy that ensures stability, for instance in the event of network problems
• Local data analysis and filtering helps to reduce network traffic
• Gateways can deploy local security solutions that help to improve overall solution security
• Gateways can ensure consistent enterprise policies across a field of work
• Decoupling gateway functionality from the hardware for on-board business logic facilitates individual lifecycles

There are many different types of M2M/IoT gateways in use today. Consumer gateways are used in home automation and security, as well as in home energy management. Specialized commercial gateways are employed in a wide range of verticals, including transportation, connected vehicles, manufacturing, and energy.

Adi Reschenhofer, CEO of Wyconn, says: “Most M2M/IoT gateways share some common features like wireless and/or wired connectivity for integration with local devices, local compute and storage capacities, as well as backend connectivity. Our M2M/IoT gateway matrix [see figure below] provides an overview of the most common gateway types and their key features.”

In the following section, we will take a look at the main features of M2M/IoT gateways before discussing current trends and recommendations for gateway selection.

Local Compute and Storage

Not only are chips getting smaller and more powerful with every generation, but today we have complete computer systems available in incredibly small sizes and at very low cost. Modern smartphones have the processing power and storage capacity of yesterday’s high-end servers. Astonishingly powerful, credit card-sized, single-board computers like the Raspberry Pi are now available at minimal cost.

At a Gartner conference in 2014, the savvy IT research firm presented its predictions for IoT processors. We have summarized our learnings in the figure below. In the presentation, Gartner focused on predicting unit shipments for IoT-enabling processors. The interesting message was that they actually foresaw a steep increase in more powerful, 32-bit microcontrollers, with slower growth predicted for 8-bit and 16-bit microcontrollers. According to Gartner, embedded processors and application processors will only represent a fraction of the processing power of the IoT.

In general, it is interesting to note that more and more domains of traditional embedded systems are now being replaced by higher-level systems, such as Linux-based platforms. This is driven by the need for functionally rich solutions, which require rich middleware functionality (for communication, for instance). Higher-level solutions are extremely expensive to develop for low-level embedded systems. The image below provides an overview of the most common IoT platforms, their main technical characteristics, and typical use cases.

Roman Wambacher, Managing Director of Dr. Wehner, Jungmann & Wambacher GmbH, provides the following explanation: Full OS systems such as Linux and Windows Embedded are now used as IoT gateways, but also for applications such as car infotainment systems. Smaller footprint systems like Intel Galileo or full embedded OS systems like VxWorks or QNX are often used for complex applications with heterogeneous devices and specialized requirements (i.e. functional safety, real-time requirements, or mission criticality), and/or because of the need to support a broad range of embedded processors and microcontrollers. Minimal embedded systems like TinyOS, Contiki, and RIOT are often used for single-purpose applications in homogeneous environments with limited local computing resources. They are also employed for sensor nodes in sensor networks. Finally, microkernel architecture – often implemented as a custom solution – is used for simple sensor nodes, and is typically optimized for size, cost, or energy consumption.

Local Wireless Connectivity

A key feature of many gateways is that they enable local wireless connectivity to distributed devices and sensor nodes. There are many different standards and technologies, most of which deal with bridging distances below 100 meters. The key differentiators are distance/range, bandwidth and latency, power consumption, and cost. The following figure provides an overview of some of the key local wireless technologies.

The following provides a very brief outline of the different technologies:

• Bluetooth low energy: Probably the technology with the largest ecosystem (smartphones, tablets, etc.). Low power, good range, moderate data rates
• 15.4: Low-level standard used in closed ecosystems like smart energy. Foundation for higher-level standards like ZigBee and WirelessHART
• ZigBee: Strong focus on low power consumption. Targeted towards smart meters, home automation, sensor networks, remote control units, etc. Especially useful for battery-operated devices
• Wi-Fi: Widely adopted, high data transfer rates. But also high power consumption and relatively complex infrastructure requirements
• NFC: Low power, but also very short range
• IrDA: Good data transfer rates, but requires line of sight

Backend Connectivity

In order to integrate the gateway with a remote backend over a long distance, gateways usually have to rely on technologies such as satellite communication, carrier networks (2G, 3G, 4G), Low Power Wide Area networks (LPWA), Metropolitan Area Networks (MANs), or fixed-line/power-line communication. Because this is an important and complex area in itself, we have dedicated the next technology profile in this section to this topic (M2M/IoT Communication Services).