Vahid Manian, Chief Operating Officer, Morse Micro
Through the application of smart technologies including machine-to-machine (M2M) communications and Industrial IoT (IIoT), Industry 4.0 is having a huge impact. Virtually synonymous with Industry 4.0, IIoT enables cost-effective, reliable, and secure wireless connectivity for sensors, actuators, instruments and other IoT devices networked throughout modern manufacturing plants, warehouses and energy grids. Think of IIoT as the logical of evolution of distributed control systems (DSC), which have been in use for decades.
According to a recent report by Meticulous Research, the IIoT market is expected to reach $263.4 billion by 2027, with a CAGR of 16.7 percent during the forecast period of 2020 to 2027. IIoT adoption is especially strong in manufacturing and assembly, logistics, oil and gas, transportation, aviation, and energy and utilities.
IIoT technology enables productivity improvements, more efficient manufacturing processes, and the production of higher quality goods and processed materials. Increasing the density of wireless sensors and controls interacting with cloud-based analysis tools provides more feedback and enhances predictive maintenance for manufacturing plants. Monitoring the health and efficiency of capital equipment improves management of these assets. However, the deployment of IoT solutions in industrial applications has been restricted by the practical and financial limitations of wireless connectivity technology available today. This is about to change.
Introducing Wi-Fi HaLow for the IIoT
Specified by the IEEE 802.11ah task group, Wi-Fi HaLow is a new wireless standard that will help make IIoT connectivity a practical reality for many manufacturing plants, production lines and warehouses. Wi-Fi HaLow’s unique combination of secure, long-range, low-power and high-performance connectivity vastly increases the number of process automation functions that can be implemented wirelessly (Fig. 1). Wi-Fi HaLow enables thousands of wireless battery-powered sensors and actuators to be securely connected to a single access point (AP), transforming IIoT as we know it.
Distributed control systems and programmable logic controllers (PLCs) traditionally have been installed at the edge of plant networks with shared-wired connections. Wireline local area network (LAN) connections such as IEEE 802.3 Ethernet often have been used to ensure rapid, secure data communications. IEEE 802.11 wireless LAN solutions also have been deployed in some industrial control applications to connect end points where line power is available, and where the distance from the Wi-Fi AP is relatively short, within 100 meters.
Given the diversity of industrial applications and communications requirements, wireless network vendors have been struggling to provide the optimal wireless solution capable of addressing the wide range of IIoT use cases. Many wireless technologies today involve complex mesh networks, derived from IEEE 802.15.4 radio platforms such as Bluetooth mesh or Zigbee. These mesh solutions were developed as personal area networks (PANs) for short-range and even body-worn products ranging from headphones to smart LED bulbs.
Efforts to extend these PAN standards into full LAN solutions have required significant compromises in performance, reach and power. Mesh networks built on 2.4 GHz radio devices often come with incomplete media access control (MAC) architectures, resulting in severe network congestion or latency issues. These problems escalate as node counts and relay hops increase. Wireless technologies like Bluetooth mesh that advertise 32,000 addressable nodes or Zigbee, which touts 65,000 nodes, in reality have very low capacity in large mesh environments. Furthermore, the use of PAN technologies requires additional layers of protocol gateways or hubs to convert data to L3 packets for IP connections.
Wi-Fi HaLow was designed from the ground up to be IP addressable, support high capacity and enable long-range connectivity. For these reasons alone, HaLow is an optimal wireless technology outperforming other Personal Area Networks (PAN), Local Area Networks (LAN) and Low-Power Wide Area Networks (LP-WAN) for industrial process and control functions (Fig. 2).
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Fig. 2: Wi-Fi HaLow performance versus other Personal Area Networks (PAN), Local Area Networks (LAN) and Low-Power Wide Area Networks (LP-WAN) for industrial process and control functions
Wi-Fi HaLow includes full MAC capability, higher data bandwidth, and stronger authentication and encryption security protocols. In addition, sub-GHz Wi-Fi HaLow signals can reach longer distances at lower power while supporting L3 packets out of the box. The HaLow standard supports 8,191 nodes per access point, and its star network topology guarantees low network congestion and low latency.
The benefits of Wi-Fi HaLow for IIoT can be summarized in four key points: range, power, spectral efficiency, and security. Let’s explore each of these benefits in more detail.
Long Range, Low Power
The IEEE 802.11ah Wi-Fi HaLow protocol was purposefully designed to tackle use cases that are not addressed by traditional Wi-Fi. The lower sub-GHz frequencies and narrower band RF channels of HaLow provide 10x the reach of 2.4 GHz Wi-Fi at the same transmitter power levels. A HaLow AP can cover 100x the area and 1000x the volume of traditional Wi-Fi APs. Wi-Fi HaLow also supports ultra-low-power modes, enabling battery-operated IoT devices to run on a coin cell for many years. When paired with thermal or vibration energy harvesting solutions, wireless sensors based on HaLow can last indefinitely in the field.
The use of Wi-Fi HaLow enables gas and fluid meters to be placed in difficult locations where there is no convenient power source or nearby PLC. For example, placing a vibration monitor in a dangerous location to listen to a pump bearing can enable predictive maintenance while improving worker safety. Reductions in the cost of labor and low power consumption quickly offset the expense of deploying wireless sensor technology. With HaLow, manufacturing and processing plants can be designed with more wireless connections that are easier to add, move and change over time.
Noise Immunity in an Unlicensed Spectrum
Wi-Fi HaLow operates in the global, license-free industrial, scientific, and medical (ISM) radio frequency bands below 1 GHz. Available sub-GHz frequency ranges vary around the world; 902 MHz to 928 MHz is available in the US, 863 MHz to 868 MHz for Europe.
Within the ISM band, Wi-Fi HaLow can use a variety of channel bandwidths including 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz. The narrower the bandwidth, the farther the signals can travel, which is a significant benefit for industrial applications in large factories and sprawling campuses.
For a wireless technology to be suitable for IIoT applications, a robust connection is as important as secure data transmissions. Wi-Fi HaLow enables data to be transmitted in packets spread across multiple sub-channels using orthogonal frequency-division multiplexing (OFDM) modulation. This technique enhances wireless performance in challenging RF environments, especially when other radio devices generate strong interference.
Forward error correction (FEC) encoding provides additional protection for recovering packets, ensuring ultra-robust connections. Wi-Fi HaLow radios with highly selective filters and extremely linear front-end architectures provide exceptional receiver performance even in the presence of large, out-of-channel interferers in dense wireless deployments. This architecture works for all regions worldwide using a single hardware platform.
Protection of data packets that control factory operations is a critical concern. Wi-Fi HaLow radio products are tested and certified to comply with today’s highest security guidelines including the new WPA3 standard. This provides the basis for the authentication of devices connecting to the AP and strong encryption of data over the airwaves. HaLow is as secure as the latest versions of the Wi-Fi standard. Wi-Fi HaLow radio devices from Morse Micro also add unique, unclonable fingerprint technology to each chip. With this feature, a secure boot and signed/encrypted data transfer to trusted platforms in the enterprise or cloud can be supported using a protocol like transport layer security (TLS). Additional host application processor functionality can address the needs of proprietary solutions.
These security functions ensure that hacker exploits are thwarted to protect valuable plant data or prevent malicious control signals from being inserted into end devices that are critical to safe, reliable IIoT operations. In addition, over-the-air (OTA) firmware updates to improve security can be implemented with Wi-Fi HaLow products. Because Wi-Fi HaLow’s high data rates enable fast firmware updates, IoT devices can be updated continuously for security, unlike other low-data-rate technologies.
Large 802.15.4 mesh networks face congestion issues that limit their throughput and therefore hinder the delivery of firmware updates. The same congestion delays the acknowledgements of completed tasks back to the host. In an IIoT environment where minimal downtime can be tolerated for firmware updates, Wi-Fi HaLow provides a faster and more reliable solution for OTA updates and security.
Wi-Fi HaLow: Extending the Possibilities of IIoT
Growing demand or factory automation and flexible manufacturing solutions has driven IIoT technology to the forefront of today’s industrial control systems. There is no question that IIoT plays a critical role in industrial automation. The question is which wireless technology provides the optimal solution to connect an array of sensors, actuators and other IoT devices.
Today’s leading wireless technologies, ranging from standards-based to proprietary solutions operating in sub-GHz and 2.4 GHz bands and even higher frequencies, were developed to address specific application and market challenges. While industry pundits often advise there’s no “one-size-fits-all” wireless solution and that many IoT applications will use a mix of protocols, it makes sense to reduce network complexity by minimizing the number of wireless technologies in use. Of all the wireless PAN and LAN technologies available, Wi-Fi HaLow offers the right balance of features and capabilities to address the diverse requirements of IIoT networks.
The Wi-Fi HaLow standard offers significant advantages over alternative 2.4 GHz wireless PAN/LAN technologies. HaLow extends wireless range, minimizes power consumption, reduces latency, and enables secure connections for a wide range of IIoT applications. A new breed of wireless sensors and actuators enabled by Wi-Fi HaLow ICs will provide manufacturers with faster, more reliable, and more secure cloud-based insight into plant operations and controls.