With current technologies and innovations wireless data transmission via mobile communication is now reliable and affordable. However, data volume per user is rising exponentially. Causes are not only the continuously growing number of smartphones, but also trends as car-to-car (C2C) or machine-to-machine (M2M) communication - cars and machines need to communicate in high speed with each other. From 2020 the 5G mobile standard is aiming to transmit data rapidly and efficiently. For that purpose Fraunhofer is developing new power amplifiers based on GaN (gallium nitride).
There are over 8 billion wireless devices currently in circulation today. Chatting with friends and the family, watching videos while on the road, playing online or simply surfing the Internet can be done without problems and is affordable. The current technologies are great for now, however, as the number of users increase and the data volume increases, the current technologies will not be able to sustain the required increase in data volume.
So far, it is mainly humans who are communicating with each other using mobile communication devices. In the future, cars, devices, or production machines will join the networks. However, real-time radio communication is necessary for visions such as Industry 4.0 or autonomous driving. Maximum data rates of 10 gigabits per second are needed and thus targeted. However, today's 4G LTE mobile standard is designed for 300 megabits per second and does not support real-time transmission. Surfing the Internet on your mobile device is comparatively slow with an average peak data rate of 50 megabits per second. For this reason, wireless carrier and network equipment providers are working jointly with researchers on the more powerful 5G. The new cellular network standard will enable the live transmission of high-quality video.
Developing technology for higher radio frequencies
The base stations are an important component in the cellular network. They are the bottleneck through which all data must pass. Researchers at Fraunhofer IAF are developing power amplifiers that are able to send more data faster and above all more efficiently through the cellular network. The first step required is for 5G networks to go higher in frequencies to 6 GHz, current LTE is limited to the 2.7 GHz band. Higher frequencies mean faster data transmission, but unfortunately also less available power for the transmitters. For this reason, the scientists are manufacturing transistors and microchips on GaN that are only a few square mm in size. Gallium Nitride is semiconductor material that is ideal for high power, high efficiency applications.
For every transmitted bit, the wireless transmission of data consumes power. That alone makes up about 15 percent of a cellular invoice. Currently each bit of information transmitted requires a certain, constant amount of power. As the data requirements increase and the number of bits transmitted increase, the energy requirements will also increase proportionately. So if the data requirements increase 200 times, then the power requirements will also increase proportionately. To avoid/solve this problem, the efficiency of cellular communications needs to be improved drastically, specially for 5G.
Currently, base stations are only able to transmit high data rates with a very high energy expenditure. The root cause is that they transmit the radio waves into the air – without knowing where the users are located. However, with new electronically steerable antennas and GaN-based power amplifiers, the information reaches the receivers with pinpoint accuracy and much more efficiency resulting in a much lower energy bill. Equipped with the technology of the researchers from Freiburg, the antennas of the base station electronically aim at the receiver. Its like the human ear: We know from which direction noises are coming from without turning our head.
GaN seems to be one of the best technologies which can be used to develop power amplifiers for 5G. However at this point power savings during operations exceed the production costs, in comparison to silicon, of the still more expensive GaN. GaN is an important component of blue and white LEDs. The success of this light technology has contributed to the production of GaN becoming ever more cost-effective. Over the last year, we have seen a number of companies who have already started to push GaN solutions for commercial applications. As the demand for this technology increase, the price points are expected to come down significantly. Subject to the prince coming down, GaN seems to be the most viable technology for powering the 5G wireless infrastructure.
