The threat behind the promise that 5G can deliver up to 1,000 times more data than today’s networks is that it could consume up to 1,000 times more energy. Concerns about energy efficiency are starting to emerge at conferences surrounding 5G deployments, where people talk about ways to reduce energy consumption.
The International Telecommunication Union (ITU) has published difficult and measurable requirements for data rates, latency, and reliability that networks must meet to be called 5G. The ITU also aims to improve energy efficiency, but has not set measurable targets.
Emil Bjornsson, an associate professor at Linköping University in Sweden, is devoting part of his current research to solving this problem. Despite the difficulties, he remains optimistic. “It’s a big problem, but I don’t think it’s a decisive one,” Bjornsson said.
Bjornsson said this despite concerns about the increasing number of small cells and the rise of massive multiple-input multiple-output (MIMO) antennas, two elements expected to become fundamental parts of 5G networks. He said so.
For small cells, the Small Cell Forum predicts that 5G small cell deployment will overtake 4G small cells by 2024, with a total installed base of 13.1 million 5G or multimode small cells by 2025, accounting for more than a third of the total installed base. is predicted to account for . Of the total number of small cells in use.
Bjornsson acknowledges that deploying more small cells will increase the total energy consumption of the network. However, he points out that the energy consumption of small cells is much lower than traditional cells. However, more small cells are needed to cover the area. Therefore, it is difficult to predict what the net energy consumption will be.
When it comes to Massive MIMO, this technology involves the use of arrays with more antennas at each base station. As a result, there are many more hardware components per base station. Bjornsson believes that this will probably increase the total energy consumption of 5G base stations compared to 4G. However, as massive MIMO technology develops, its energy efficiency is likely to improve over time.
“Just as computer processors become significantly more efficient over time, the analog and digital circuits used in base stations also become more efficient,” Bjornsson said. “His first generation of 5G hardware is intended to bring all new features to the market, but after that he will also need time to improve the hardware.”
As evidence that this is likely to happen, a European Union project called the MAMMOET project shows that future Massive MIMO base stations will have more hardware than 4G base stations. We predict that energy consumption will be lower.
The benefit of massive MIMO hardware improvements over time is that the equipment will be able to serve more users on the same frequency at the same time. This feature is called spatial multiplexing, so energy consumption is distributed among users. “If you spatially multiplex 10 users, and for that he has to spend twice as much energy, the energy efficiency will be five times greater,” says Bjornsson.
Bjornsson said that for both 4G networks and future 5G networks, carriers will likely operate their base stations to transmit at the maximum power allowed by their licenses to maximize coverage. It will be. As a result, there are direct savings in transmission when comparing his 5G base station with his 4G base station located in a similar location (rooftop or mast) and using common cellular frequencies from 1 to 5 gigahertz. is not expected to be found.
However, there is one special feature that reduces the energy demands of 5G networks. That is, 5G base stations can go into “sleep mode” (referred to as “ultra-lean design”) whenever there are no active users.
“This happens much more often than you might think,” Bjornsson says. “4G networks need to transmit large amounts of control signals even when no one is listening, such as at night.”
Recent research shows that the ultra-lean design that 5G networks are capable of will allow more components to sleep for longer periods of time, consuming less energy when no users are present compared to current systems. can be reduced by almost 10 times.
Looking outside of the specific technologies associated with 5G networks, such as Massive MIMO, we find that even if new technologies are more energy efficient and consume less energy, it will take time for them to become widespread enough to make a noticeable difference. There is a common problem that it takes. According to Bjornsson, via the network. But he believes the ongoing shift to software-defined networking equipment could change that. He added: “If we can deliver new features as software updates that make the system even more energy efficient, it will be much easier to improve efficiency over time.”
