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ISO/IEC 14543-3-10 – a new wireless standard

Compared to wired systems, wireless offers far greater flexibility and convenience in home and building automation, as well as in industrial installations. However, choosing the right wireless radio system is a challenge in a competitive market which offers a variety of different products, based on diverse wireless protocols, from a wide range of manufacturers.

Increasingly, system integrators, electrical installers, specifiers, architects and property owners must make a choice. With ISO/IEC 14543-3-10, the International Electrotechnical Commission (IEC) has recently ratified a new international wireless standard. The particular: It is the first and only wireless standard for wireless applications with ultra-low power consumption also optimised for energy harvesting solutions. So what is the new standard about, what are its specifications and application benefits?     

Energy harvesting has nestled its way into our everyday lives. Today, energy-autonomous wireless systems are found in all kinds of buildings, in industrial plant and many other sectors. Energy harvesting wireless modules gather the power they need to operate from the environment around them – from motion, light or changes in temperature – and, in doing so, make electronic control systems independent of an external power supply. Even humans can serve as a source of energy, generated by pressure on a button or heat given off by the body. The ambient energy obtained in this way, given a suitable low power wireless controller is sufficient to send a wireless signal as a command and control message.

Established energy harvesting
A key market for energy harvesting wireless technology is building or home automation, as most automated functions in a building only require short term wireless transmission of small amounts of information. Harvesting devices include light switches and devices transmitting the information from wireless sensors such as air-conditioning controls, occupancy sensors and CO2 detectors. All these applications require a wireless protocol that operates on relatively low power. EnOcean is a pacesetter in this field with its energy harvesting wireless modules that allow the implementation of fully energy-autonomous applications for automation. The messages sent by this wireless system are extremely brief and are repeated several times within a 40 millisecond time frame. By transmitting these data packets at random intervals, it is possible to ensure that the probability of collision and interference is extremely small. As a result, there is no issue with operating a range of switches and sensors in close proximity to each other.

Demand for interoperability
A major requirement of reliable and cost-efficient systems is interoperability between the products of different manufacturers – which is why building automation calls for standardised technologies. Interoperability of different end-products based on energy harvesting technology has been an important success factor for establishment of the technology on the market. For this reason a de facto wireless standard has been established by EnOcean and deployed through the EnOcean Alliance – a consortium of companies working to further develop and promote self-powered wireless monitoring and control systems for sustainable buildings by formalising standardised application profiles. This ensures that sensors from manufacturer “A” are able to communicate with receiver gateways manufactured by vendors “B” through “D” in the eco-system.

Standard for low power
Now these principles have been enshrined in the new standard, ISO/IEC 14543-3-10, which provides a "Wireless Short-Packet (WSP) protocol optimised for energy harvesting - Architecture and lower layer protocols”. The protocol is efficient enough to support energy harvested products for sensors and switches that do not require wires and batteries. It is the only standard specifically designed to keep the energy consumption of such sensors and switches extremely low, an order of magnitude lower than alternative standards. It achieves this by transmitting multiple, very short transmissions; and by selecting radio frequency bands with excellent signal propagation and minimal interference. The result is reliable, wireless communication that is energy efficient but long range, allowing the use of small, cost-effective, maintenance free energy harvesters that can compete with similar battery-powered devices.

Less crowded frequency
The standard utilises the less crowded 868 MHz and 315 MHz frequency bands, making it suitable for use worldwide. This provides a safeguard against other wireless transmitters, whilst offering fast system response and elimination of data collisions. This makes the 868 MHz and 315 MHz band much more suitable for reliable building automation than, for example, the 2.4 GHz band. In addition, 868 MHz radio waves have twice the range of 2.4 GHz signals, and double the penetration through materials like walls and furniture. As a consequence, a 2.4 GHz system requires about four times more receiver nodes area-wide. That increases its cost compared to an 868 MHz solution, for example. Telegrams transmitted by the standard are just 0.7 milliseconds in duration and are transmitted at a data rate of 125 kilobits per second. The range of standard-based wireless sensors is about 300 metres in an open field and up to 30 metres inside buildings.

In many respects the structure of ISO/IEC 14543-3-10 is identical to most wireless standards where upper layers of the protocol (creating interoperable products) are governed by technology alliances and sit on top of the radio – physical and data link layer defined by an open international standard. This is the case with Bluetooth and IEEE 802.15.1, Wireless HART/ZigBee/RF4CE and IEEE 802.15.4, or WiFi and IEEE 802.11.

Where other wireless standards integrate physical and data link layers and the network layer is integrated in the protocol stacks, in the case of ISO/IEC 14543-3-10, the standard offers physical and data link layer as well as the network layer, with the EnOcean Alliance offering the application level. These application profiles sit on top of ISO/IEC 14543-3-10 and are defined in order to achieve interoperability between products from different vendors. These application level protocols are referred to as EEPs (EnOcean Equipment Profiles).   

Potentials of the new standard
Based on the open standard any manufacturer can now develop and build products. For example, a transceiver or a module which is “EnOcean compatible”. There are already over 850 products developed by the members of the EnOcean Alliance according to the standardised technology. With this rich ecosystem of field-proven devices adhering to the standard, developers and manufacturers can therefore benefit from this extensive practical experience, huge product range and installed base.

An example for a standard-based application is the stop button for buses from BMAC. While other pushbuttons need to be connected to the signal at the driver’s position via metres of cable, this stop button functions with a small battery-free microchip. When a passenger presses the stop button, the EnOcean energy harvester converts this small movement into electrical power and a radio signal is sent to the receiver module. This activates the stop display and the audible stop signal. The transmitted radio signal is unique to each stop button, so there is no interference with other buttons in this bus or other buses nearby. The receiver module is connected to the vehicle electronics. After installation, each stop button in the bus is programmed for its own logic circuit – for example, front, middle, rear or wheelchair users. The self-powered solution saves up to 100 metres of cabling in the bus, and there is no longer any need to replace defective cables, which can be time-consuming.

Sensors and switches are a vital part of systems which save energy and increase comfort as well as safety. The combination of miniaturised energy harvesting modules with ultra-low power radio technology is the basis for innovative maintenance-free wireless sensors which add unparalleled flexibility at the lowest investment and operational cost. The new wireless ISO/IEC standard will accelerate the development and implementation of energy-optimised wireless sensors and wireless sensor networks. It will open up new markets and areas of application for energy harvesting solutions and thereby innovative technical solutions for more energy efficiency. In addition to the already established markets for home and building technology, there will be further uses of wireless energy harvesting ranging from smart home, smart metering and the smart grid to solutions for industry, logistics and transport.

By: Laurent Giai-Miniet, CEO of EnOcean

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