Wireless industrial networks will become the standard: technologies, protocols, and implementation

Why wireless industrial networks are replacing cables

For decades, wired Fieldbus, Profibus, and Modbus RTU networks remained the only option for communication between controllers, sensors, and actuators. They provided reliable data transfer but required significant investment in cable infrastructure: conduit installation, shielding, and electromagnetic interference protection. According to leading industry analysts, cable infrastructure accounts for 40 to 60 percent of the total automation budget for a facility. This single factor has become the primary driver behind the transition to wireless industrial networks.

Modern manufacturing demands new capabilities: equipment mobility, rapid line changeover, and data collection from hard-to-reach areas. The traditional wired approach becomes an obstacle for flexible production systems. Wireless protocols allow deploying a sensor network in days rather than weeks, without shutting down the production process. This is particularly relevant for facilities modernizing existing equipment or deploying smart sensors on already operating sites.

WirelessHART: the first standard that proved reliability

WirelessHART (IEC 62591) became the first internationally recognized wireless communication standard for industrial automation. Ratified in 2010, it is built on IEEE 802.15.4 and operates in the 2.4 GHz band using TDMA (Time Division Multiple Access) technology and frequency hopping. Each packet is transmitted on a different frequency, significantly improving interference resistance even in the harsh electromagnetic environment of industrial plants.

The main advantage of WirelessHART lies in its compatibility with the existing HART device ecosystem. Facilities already using HART sensors and HART transmitters can gradually transition them to wireless communication without replacing the instruments themselves. It is sufficient to install a wireless adapter on an existing HART device and a gateway that collects data and forwards it to the control system.

A WirelessHART network is built on the principle of a self-organizing mesh: each node can act as a relay for neighboring devices. If one route becomes unavailable due to obstacles or failure, data is automatically rerouted through an alternative path. Experience from large oil refineries shows that WirelessHART networks with several hundred nodes achieve packet delivery reliability of 99.7 percent and above.

ISA100.11a: flexibility for complex facilities

The ISA100.11a standard (IEC 62734) was developed by the ISA organization as an alternative approach to industrial wireless communication. Unlike WirelessHART, it is not tied to a specific upper-layer protocol and allows tunneling various protocols: HART, Foundation Fieldbus, Profibus, and Modbus. This makes ISA100.11a a universal solution for facilities with mixed infrastructure, where devices of different generations and manufacturers coexist.

ISA100.11a also uses the 2.4 GHz band, TDMA, and frequency hopping, but features a more flexible routing architecture. The standard provides three types of network topology: star, mesh, and combined. This allows adapting the network to specific site conditions: for open areas, a star topology with a larger radius is more efficient, while for workshops with metal partitions, a mesh with multiple paths works better.

In practice, both standards — WirelessHART and ISA100.11a — often coexist at the same facility. Gateways of modern industrial controllers support both protocols, giving engineers freedom to choose the optimal solution for each specific task. For example, WirelessHART for monitoring temperatures and pressures, and ISA100.11a for integrating existing Fieldbus segments.

Wi-Fi 6 and 6E: industrial transformation of a classic standard

Wi-Fi was long considered an exclusively office technology, unsuitable for shop floor conditions. However, Wi-Fi 6 (802.11ax) and Wi-Fi 6E standards fundamentally changed the situation. Key innovations that made Wi-Fi suitable for industrial applications:

• OFDMA (Orthogonal Frequency Division Multiple Access) technology, enabling simultaneous service of dozens of devices without competitive channel access
• Target Wake Time (TWT) — a device activity scheduling mechanism that radically reduces power consumption of battery-powered IoT sensors
• Support for the 6 GHz band (Wi-Fi 6E), which is significantly less congested in industrial environments than the traditional 2.4 and 5 GHz bands
• BSS Coloring — protection against inter-network interference in dense deployments where multiple access points operate in the same workshop
• Increased throughput up to 9.6 Gbps — sufficient for transmitting video from quality control cameras and streaming vibration diagnostics data

Specialized industrial Wi-Fi 6 access points are manufactured in IP67-rated enclosures, withstand vibration, and operate in an extended temperature range from minus 40 to plus 75 degrees Celsius. Automation equipment manufacturers, including Siemens (SCALANCE), Cisco, and Moxa, offer solutions with deterministic latency below 1 millisecond for real-time applications.

Wi-Fi 6 is particularly effective for communication with operator panels and mobile terminals where high throughput and bidirectional data exchange are required. Combined with OPC UA or MQTT protocols, industrial Wi-Fi networks become a full-featured transport layer for Industry 4.0 systems.

Private 5G networks: a new level of industrial connectivity

Private 5G networks have become one of the most discussed technological solutions for industrial automation. Unlike public mobile operator networks, a private 5G network is deployed directly on the facility premises using dedicated spectrum or a local license. This guarantees full control over latency, bandwidth, and data security.

Advantages of 5G for the industrial environment:

• Ultra-low latency (URLLC) below 1 ms — critical for closed-loop control and remote robot operation
• Massive device connectivity (mMTC) — up to one million nodes per square kilometer, covering the needs of even the densest production sites
• High mobility — continuous connectivity with automated guided vehicles (AGVs), cranes, and mobile robots while in motion
• Network Slicing — the ability to create virtual networks with different quality parameters: one for critical control, another for video surveillance, a third for office traffic
• Large area coverage — a single base unit provides connectivity within a radius of several kilometers, ideal for mining quarries, ports, and logistics hubs

In Europe and Asia, dozens of enterprises have already deployed private 5G networks. BMW at its Regensburg plant uses 5G for communication with mobile robots on the assembly line. Bosch uses a private network for real-time quality control data transmission.

LPWAN: long-range technologies for distributed facilities

For tasks requiring long transmission range with minimal power consumption, there is a class of LPWAN (Low Power Wide Area Network) technologies. The most common protocols in this class are LoRaWAN and NB-IoT.

LoRaWAN

LoRaWAN operates in the unlicensed 868 MHz band (in Europe) using spread spectrum modulation. Communication range reaches 15 kilometers in open areas and 2-5 kilometers in urban environments. Battery-powered devices operate for up to 10 years due to ultra-low power consumption.

In industry, LoRaWAN is used for monitoring remote facilities: pipelines, tanks, electrical substations, and water treatment plants. A typical scenario involves transmitting temperature, pressure, or fluid level readings several times per hour. For managing frequency converters at pumping stations on remote water supply segments, LoRaWAN can transmit commands and status information without laying kilometers of cable.

NB-IoT

NB-IoT (Narrowband IoT) uses licensed mobile operator spectrum and operates as an overlay on existing LTE infrastructure. Its advantages include guaranteed coverage (wherever mobile service exists), better indoor penetration due to the narrowband signal, and centralized operator-managed security.

For industrial enterprises, NB-IoT is attractive because it eliminates the need to build proprietary network infrastructure. It is sufficient to purchase NB-IoT modules and connect them to an operator cloud platform. This reduces initial investment but creates dependency on a third-party connectivity provider.

Bluetooth 5.x Mesh and Zigbee: local industrial networks

Bluetooth 5.x with mesh topology support and Zigbee 3.0 occupy the niche of local industrial networks with short range but high node density and low power consumption.

Bluetooth Mesh allows creating a network of thousands of nodes where each device relays messages to neighbors. Typical applications include condition monitoring systems where dozens of vibration and temperature sensors are placed on electric motors, pumps, and compressors. Bluetooth 5.x provides a range of up to 200 meters in open space and throughput of up to 2 Mbps, sufficient for transmitting diagnostic data.

Zigbee 3.0 is used primarily in building automation and lighting systems but also finds applications in light industry. The protocol supports up to 65,000 nodes per network and has built-in security mechanisms based on AES-128. Expansion boards of certain industrial controllers support Zigbee, allowing integration of wireless sensors without additional gateways.

Comparison of industrial wireless technologies

Security of wireless industrial networks

Cybersecurity is the key barrier to adopting wireless technologies at critical industrial facilities. However, modern protocols feature multi-layered protection mechanisms.

WirelessHART and ISA100.11a use AES-128 encryption at the link layer, device authentication through shared keys, and message integrity control (MIC). Frequency hopping makes traffic interception difficult, while TDMA access prevents collision-type attacks.

Wi-Fi 6 supports WPA3 with protection against dictionary attacks (SAE — Simultaneous Authentication of Equals) and individual encryption for each client. Private 5G networks use SIM-based authentication, end-to-end encryption, and network slice isolation.

General recommendations for wireless industrial network security:

1. Network segmentation: isolate critical control loops from information networks
2. Deep Packet Inspection (DPI) at gateways between wireless and wired network segments
3. Regular firmware updates for wireless devices and access points
4. Radio frequency monitoring for unauthorized devices and interference sources
5. Implementing IEC 62443 as a comprehensive framework for industrial systems cybersecurity

Convergence: the future belongs to hybrid networks

At a real industrial facility, a single wireless technology is rarely used alone. A typical modern enterprise combines several protocols into a unified hybrid network. For example:

• WirelessHART or ISA100.11a — for monitoring process parameters (temperature, pressure, flow) in process manufacturing
• Wi-Fi 6 — for operator panels, mobile maintenance terminals, video analytics cameras, and augmented reality
• 5G — for communication with AGVs, mobile robots, and real-time remote control
• LoRaWAN or NB-IoT — for remote monitoring of distributed assets (pipelines, substations, tanks)
• Bluetooth Mesh — for equipment condition monitoring, asset tracking, and personnel positioning

All these networks connect through unified gateways and Industrial IoT platforms, where data is aggregated, analyzed, and forwarded to management systems (SCADA, MES, ERP). The OPC UA protocol is becoming the standard language for interoperability between different wireless and wired segments. Modern frequency converters already have built-in support for wireless protocols or the ability to add it through expansion modules.

Practical implementation recommendations

Transitioning to wireless industrial networks requires a systematic approach. Before choosing a specific technology, it is necessary to conduct a radio survey (site survey) of the facility, identify sources of electromagnetic interference, and assess latency and reliability requirements for each control loop.

Key implementation steps:

1. Audit existing infrastructure and identify tasks that are suitable for wireless communication
2. Radio survey of the facility, accounting for metal structures, moving equipment, and other signal attenuation factors
3. Pilot deployment on a limited area with measurement of actual reliability and latency metrics
4. Integration of wireless gateways with the existing control system and databases
5. Scaling based on pilot project results and personnel training

Wireless industrial networks are no longer an experimental technology. They have become a standard modernization tool that enables enterprises to reduce cable infrastructure costs, increase production flexibility, and gain access to previously unavailable data. The choice of a specific protocol depends on site conditions and latency and range requirements, while the optimal approach is building a hybrid network that combines the advantages of several technologies.