Higher networking, lower power consumption
Due to the explosion in the number of networked devices and the rapidly increasing data volumes, energy efficiency is becoming increasingly important when it comes to wireless technologies. New materials and intelligent, application-specific wireless processes ensure that, despite increasing networking, power consumption does not increase at the same rate.
Networked IT applications can make a significant ecological contribution, with the smart grid or intelligent traffic management systems being only two examples of this.
Up to 9 billion metric tons of CO2 could be saved globally in this way, according to estimates by the Global e-Sustainability Initiative (GeSI).
On the flip side, however, networked systems also require energy: “Even now, Internet users need gigantic amounts of electricity for streaming music and films,” says Niklas Schinerl, Greenpeace expert for energy. “If the Internet were a country, it would have the sixth-highest energy consumption in the world.”
Taking into consideration how rapidly both the number of networked devices as well as the volume of data being transferred is set to rise in the next few years, one thing is clear: energy efficiency is a crucial topic for networking.
Every transferred bit requires energy
This applies in particular to wireless technologies, as every bit of information requires a certain amount of energy in order to be transmitted wirelessly. Researchers and industry are therefore pursuing various strategies in order to improve the energy efficiency of wireless applications. The first approach consists of tailoring the wireless processes to the actual requirements of the data transfer.
Not every IoT device needs to be online constantly, or have the ability to transfer enormous data volumes in a short amount of time. For example, with the Bluetooth Low Energy (BLE) standard, the device remains in standby most of the time. Only when data actually needs to be transferred does the device wake up and transmit a short message. Additionally, with BLE, everything from the physical design to the application models is designed to keep power consumption to a minimum. This reduces active power consumption to a tenth of that for classic Bluetooth. In this way, a button-cell battery can ensure reliable operation lasting five to ten years in applications with low duty cycles.
Billions of networked things need electricity
In terms of the Internet of Things in particular, wireless devices which use energy sparingly play an important role, including for wide area networks (WAN). Many IoT applications are based on smaller, inexpensive battery-powered devices. They collect and transfer only minimal data volumes, often at irregular intervals, and can be spread out over sprawling areas. Sensor networks in smart cities are a typical example. The number of devices could increase into the millions, and users expect that they will function not only for a few years, but rather decades without any great need for maintenance. They therefore place similar requirements on wireless technology as PAN applications, but need to be able to transfer data over far longer distances.
There are now numerous technologies which have been specifically tailored to these requirements, for example LoRaWAN, Weightless, NarrowBand-IoT and Sigfox. The latter is a system from the French company of the same name, which is developing its own low-power WAN using the transmission standard. The energy requirement for this is very low, as the solution only transfers short messages of 12 bytes per message at a relatively low speed of 100 bps.
Smaller mobile communication cells reduce power consumption
In contrast, other applications in the Internet of Things are comparatively data-intensive and require high transmission rates, for example solutions for autonomous driving. This requirement will be fulfilled by the future 5G mobile-communication standard, which will increase the network’s data capacity a thousandfold in the course of the next decade.
At the same time, however, the aim is to halve the global energy consumption of mobile-communication networks. In order to achieve this, the overall efficiency of the network must increase noticeably. One step to achieving this is antenna technology – intelligent antennas no longer send their signals undirected into the air like standard transmitting stations, but rather only send a concentrated signal in the direction of the mobile-communication user. At the same time, the 5G network is being created from many smaller transmitting stations – these picocells and femtocells bring the user much closer to the relay point.
When taken as a whole, this approach significantly lowers the power requirement for signal transmission.
New materials for mobile communication electronics
The 5G electronics themselves should also only use little energy, particularly in mobile IoT applications. Power amplifiers in the base stations are the focus in this case. They provide the required radio frequencies over which the data is to be transferred. Today’s conventional systems have the disadvantage that efficiency is reduced at high frequencies.
One solution is microchips made from gallium nitride (GaN), a semiconductor material. Due to its special crystal structure, the same voltage can also be applied at high frequencies, which achieves more power.
These innovative components allow the power requirement of mobile-communication base stations to be reduced by 75 per cent in comparison to conventional technologies. The use of GaN power amplifiers for mobile-communication networks could save around 1.5 million metric tons of CO2 each year in Germany alone. This is why research into new materials for 5G electronics is worthwhile, as highlighted by Professor Hubert Lakner, Chairman of the Fraunhofer Group for Microelectronics: “New hardware components which can process the enormous data volumes with the utmost speed and the lowest energy consumption are required.”
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This article is also available in German language. Click here for the German version. 
