How to find the right radio system for every application
Pros and cons of wireless technologies like Bluetooth, WLAN, 5G and more
Manufacturing companies that want to continue to be successful in the long run, need to embrace the digitalization of processes and production. To keep up with the competition you need to utilize state-of-the-art networked technology. Wireless data transmission is a crucial component in this: Wireless is increasingly replacing cable connectors, enabling fast, secure and stable communication between components and systems. But, to choose the right one you need an overview: What technologies are out there, and how to find the technology best suited for a specific industrial application? Look no further - we are giving you the overview you need.
For the last 30 years we at Schildknecht AG have developed, produced and sold the DATAEAGLE® radio data transmissions systems tailor-made for industrial use. Our core skill is the patented, ultra-stable radio transmission of data needed in e.g. crane engineering, stage equipment, water management, cable railways, autonomous vehicles and much more. Due to pre-processing of data at the software level the system reliably prevents fieldbus errors in automation systems and thus machine downtime.
Especially, applications within automation engineering involving rotary or linear motion are ideal for data radio solutions (Blog article about wireless communication as an alternative to cables). We know that the choice of transmission technology depends on various factors, that are crucial in regards to system performance and stability.
These are the questions you need to ask to prepare yourself to make the right choice about a radio system:
- What kind of data is being transmitted?
In an industrial setting mostly control data or simple I/O data are transmitted, together with image and video data. Bluetooth for instance is a narrow-band radio technology, utilizing a very specific frequency spectrum, while transmitting on different channels simultaneously. This makes it very resilient towards interference.
WLAN however is broadband and uses a larger spectrum to transmit more data in a similar amount of time, which is preferable when it comes to streaming of image or video data. But WLAN is more prone to malfunction because it transmits on a fixed frequency and thus is unable to avoid other users. Therefore, the crucial factors to consider are the kind of data you want to transmit, together with transmission distance and energy usage.
- What is the size of the data?
Compared to cables the data throughput of a wireless system is significantly lower – at least with a factor of 1.000. Moreover, data will arrive with a short delay. The technical term for this is latency. In general, radio technologies using the free frequency bands below 1 GHz in general have higher latency and lower data throughput. Therefore, high-performance applications like for instance automated guided vehicles (AGVs) will be placed in the 2,4 and 5 GHz range, while 869 or 433 MHz will be fully adequate at e.g., a sewage plant, due to less strict real-time requirements and lower data volume such as simple sensor values.
- In which countries will you deploy radio data systems?
Using a pre-certified radio module, transmitting in a globally applicable spectrum, for instance 2.4 GHz, does not mean that you can distribute and operate your product globally. Each country and economic region has its own specific guidelines for radio communication systems. In the European economic area, it’s the Radio Equipment Directive (RED 2014/53/EU). In the US it’s the FCC. In most cases you need to request a device-dependent licence from the manufacturer, to allow for import and operation.
WLAN and Bluetooth both use the 2,4 GHz band and are global technical standards. That means you can apply for a global authorisation to use these transmission systems. In contrast, the 868/869 MHz frequency is used in Europe, while its American counterpart is the 900-915 MHz band. These frequency bands have hardly any technical standards, like for instance LoRa. The numerous proprietary radio transmission technologies are incompatible with each other. That means the distributor’s certification effort will be significantly larger.
Wireless technologies for radio systems at a glance
If you have considered these basic questions, you currently have the choice between the following radio technologies:
Bluetooth
Bluetooth is for short-range transmission of speech, music and data. However, dependent on version and performance class you can achieve transmission distances of several 100 metres, and with line of sight between transmitter and receiver it can even be up to 1 km. Furthermore, the legislators have defined a special coexistence procedure for Bluetooth, which allows for an optimized latency jitter for industrial applications, which means a lower spread of transmission times.
Apart from hands-free functions for cars and smartphones the preferred use cases for Bluetooth Low Energy (from version 4.1) are sensor applications. On the other hand, Bluetooth 2.x, and since 2020 Bluetooth 5 as well, are especially well-suited for industrial applications in automation technology: In this domain Bluetooth is in fact the currently most robust radio technology, primarily due to its frequency hopping abilities. This allows for minimal latency, and due to its multi-channel approach Bluetooth is very resilient towards interference, for instance reflections. This is why we at Schildknecht AG prefer Bluetooth in the 2,4 MHz band over WLAN for applications within automation technology.
Preferred application areas:
- Industrial automation technology
- Consumer applications
- Sensor systems
Bandwidth:
- 1 or 2 MHz in the 2,402 to 2,480 GHz frequency range
Participants:
- Numerous parallel independent radio paths with up to 8 participants on one BT base station (Master)
WLAN
For transmission of large amounts of data like video or images, WLAN would be the preferred choice. Wireless communication by Industrial Wireless LAN is already operational in many applications, for instance regarding mobile network participants like AGVs or in crane technology. Specific standards like WiFi (Wireless Fidelity, Standard IEEE-802.11) or the newest WLAN 6 (IEEE 802.11ax) offer in-depth descriptions of the system functionalities.
In addition to operating in the 2,4 GHz area, WLAN works at 5 GHz as well. Connectivity is established via fixed access points connected to the network, with an unlimited number of access points. In the 2,4 GHz band WLAN utilizes only 3 channels, to avoid interference between neighbouring routers. Due to CSMA/CA media access, which prevents network participants from transmitting simultaneously between each other (Listen Before Talk) to avoid collision, data transmission can be delayed indefinitely. This is problematic regarding data communication in control engineering, because data packets are expected within narrow time limits.
Preferred application areas:
- Mobile network participants
- Large amounts of data, e.g. image or video transmission
Bandwidth:
- 2,4 and 5 GHz, required bandwidth 20 or 40 MHz (802.11.n / WiFi 4), 80 und 160 MHz (WiFi 5 / 802.11.ac & WiFi 6 / 802.11.ax)
Participants:
- 3 independent channels at 2,4 GHz and 14 at 5 GHz, any number of participants per WLAN base station (Access Point)
EchoRing
The EchoRing technology is offering a particularly fail-safe connection between application components. Communication is highly reliable, realtime-capable, and deterministic. Its underlying “Token Ring Technology” is developed to fit into a service-level based network design. The radio system is characterized by extremely low latency (URLLC), which we have tested and documented in Schildknecht’s own test lab (Read full article). Combined with the patented DATAEAGLE® technology you can achieve reliable ultra-low latencies and real-time capability of the control system with an updating time of 1 ms.
Thus, EchoRing is suitable for solutions that require reliably low application time. In Germany, EchoRing uses the 5,8 GHz frequency band for data transfer, securing low latency and stable, interference-free operations. This makes EchoRing stand out compared to all other current radio systems.
Preferred application areas:
- High-speed use cases
- Sites which are distributed or difficult to access
Bandwidth:
- 5,8 GHz
Participants:
- 2 to 20 participants per radio channel
Proprietary technologies
Over time a great number of proprietary radio technologies have emerged. Some of them have evolved into international standards, managed and developed further by some type of organisation, like for instance the Bluetooth SIG. These organisations demand fees for patents and for using the name, together with other services. As a manufacturer, before you decide what radio technology to choose, it would be wise to examine the terms and conditions for its use. You are obligated to pay a fee to these organisations, dependent on the size of your company or units of production. However, we would advise against developing a system yourself: If it’s not a global standard, you can’t have global distribution and rollout.
5G and 5G campus networks
The latest mobile communications standard 5G allows for industrial applications. To begin with, 5G is a general term for different topics like frequency spectrum, bandwidth, data rate, latency, antenna technology etc. Only through its release versions 5G will get its specific technical definition. Currently, Release 15 specifies the technical parameters available in new 5G smartphones (enhanced mobile broad band - eMBB). Release 16 specifies industrial applications, due to its Service URLLC (Ultra-reliable Low-latency Communications), defining latency and data transmission reliability.
What’s new in this radio technology is the fact that for the first time in Germany a frequency band of 100 MHz between 3,7 and 3,8 GHz is being reserved for local applications: Private 5G campus networks.
That means companies can apply for exclusive, site specific 5G bandwidth in 10 MHz slices and use it to run their own base station. Such base stations are significantly more complex to manage, compared to a WLAN access point, which is why mobile service providers offer to operate and maintain them. An exclusive, proprietary on-site 5G base station (campus network) enables you to build your own highly reliable wireless network infrastructures, and to optimize them towards different use cases.
However, reliability is not so much related to the frequency band used but comes primarily from the exclusive use and from the 5G technology and performance classes like URLLC (ultra-reliable low latency communication). With exclusive frequency utilisation radio systems are not required to incorporate mandatory coexistence mechanisms, as is the case in the free ISM and SRD bands.
Preferred application areas:
- Industrial use cases with Release 16/17 & 18,
- Private 5G campus networks
Bandwidth:
- 3,7 to 3,8 GHz
Participants:
- Any desired number
Radio technologies compared
You might have guessed it already: There are unlimited possibilities when it comes to data transfer. Each wireless technology has its strengths and weaknesses, pros and cons. Reading this overview you might already have found out, which technology best fits your needs. But if you’re still uncertain, here we have a few more pieces of advice for you or you get in touch with us and we are happy to discuss in person.
Different frequencies and channels for data transfer
In the frequency range below 1 GHz there is only a relatively limited number of channels and thus independent data transmissions to choose from. Due to different technical procedures, Bluetooth at 2,4 GHz allows for several hundred independent parallel transmission without mutual interference. The new 3,7 – 3,8 MHz 5G campus networks, which are immediately useable, allow for up to 5 additional 20 MHz channels for local applications. In this setup, the capacity of a 5G channel can be compared to that of a WLAN channel.
Compared: Bluetooth vs. WLAN
The most significant difference between Bluetooth and WLAN is probably bandwidth and thus the fault susceptibility of both technologies. A quick reminder: Bluetooth is a narrow-band technology, which uses a small frequency spectrum and changes transmission channels constantly. This results in low fault susceptibility. WLAN however is broadband and thus uses a larger spectrum and can transmit larger amounts of data within the same timeframe. As WLAN transmits on a fixed frequency and is unable to avoid other users, it is significantly more fault susceptible than Bluetooth. If you have the choice between these two technologies, you need to prioritize: Do you have to transmit a lot of data and are you willing to accept a higher fault susceptibility? Or can you manage with a lower data transfer rate, so that you can use the less interference prone Bluetooth instead?
Bluetooth uses the license-free ISM band (Industrial, Scientific, Medical) and transmits at 2,402 to 2,480 GHz, the same frequency band as WLAN. The statuary spectral density can be higher than WLAN, making longer transmission paths possible. Another factor, at least when it comes to battery powered devices, is power consumption. This factor could point towards Bluetooth. Beyond these two there are numerous other wireless technologies that are developed and optimized for specific properties.
No matter which wireless technology you want to deploy, in any case it’s worth checking out our DATAEAGLE® wireless solution. Please contact us for a non-binding consultation appointment. We would also like to offer to send you a test system, for you to try out for four weeks - for free!
Please contact us via phone at +49 7144 89718-0 or via email at sales@schildknecht.ag. You can also use the chat function on our website. We’re looking forward to meeting you!