5G may require massive MIMO and millimeter-wave technologies to meet the demands of a heterogeneous network linking 50 billion nodes.
Today we use the 3G and 4G network for our mobile connections. We -- from the research community -- are already thinking about the next step: the 5G network.
What 5G will bring is still unclear. For sure, it will not be an upgrade of the network as we know it today. It will be a mesh of networks that connects everything and everyone: people, objects, sensors, tools, and instruments. In this way, a 5G cloud will connect 50 billion nodes by 2020.
The 5G network will be a heterogeneous network where various types of networks are connected: a network for mobile phones, a network with a high data rate for mobile HDTV, a network with a minimal latency for car-to-car communication, a network with a low data rate and energy use for sensor networks, and many more. Every network will use the wireless technology that is most suited for its applications.
Today we already have networks for mobile phones, WiFi, and Bluetooth. I expect that the number of such technologies will greatly increase. And I expect that they will all be connected into one network where everything is connected and can communicate.
We will include 5G radios in mobile phones, cars, refrigerators, buildings, and road infrastructure. A goldmine of new applications will become possible because of this. People will keep on communicating with each other but they will also communicate with machines, controlling their household appliances from their office, for example. If you integrate 5G radios in cars and parking meters, the car will pay the parking fee without you even noticing it. The technology becomes invisible.
Autonomous driving will be enabled by communication between the car and the traffic infrastructure. With the current 4G network and technology many of these applications are already possible. But that will not be possible with the capacity and connectivity needs expected for 2020. For these, we need a faster response, a more efficient use of the spectrum, and much more capacity.
If we want to connect 50 billion nodes, we'll need a network with a capacity that exceeds today's by 1,000 times. A promising technology to do that is massive MIMO. This technology uses many antennas at the base station, more than you would need for the communication. The antennas are used to create and steer the communication waves, so that the signal is directed only towards the intended receiver. On the side of the receiver, you can then do with a very simple radio, because the signal is clear. And you can reuse frequencies for many communications at the same time, because they don't interfere.
Another promising technology for 5G is the use of millimeter-wave frequencies. They offer more bandwidth, and you can reuse frequencies in a small area because the signals do not carry that far. At Imec, we've implemented efficient mm-wave radios for static in-house applications, and we are now looking at mobile outdoors applications. In these radios, we already use beam-forming to direct the signals. For mobile applications, beam-forming will have to work much faster, which certainly is a challenge for our researchers.
ó Liesbet Van der Perre is a professor at the KU Leuven and director of the green radio program at Imec in Leuven, Belgium.