A new chip component designed by MIT researchers promises to expand the reach of the Internet of Things into 5G. This discovery underscores the growing momentum for 5G-based IoT technology, leveraging the low latency, energy efficiency, and massive device connectivity capabilities of the telecom standard. The research marks a significant advancement toward applications such as smaller, low-power health monitors, smart cameras, and industrial sensors.

Essentially, migrating the IoT to 5G offers the potential for faster connections, greater data speeds, reduced battery consumption, and broader connectivity. However, this transition also necessitates more sophisticated and complex circuitry to manage the increased data flow.

By adhering to 5G standards, as opposed to relying on 4G/LTE or Wi-Fi networks, IoT can extend its range and capabilities. This allows for the expansion from smaller IoT deployments to larger networks capable of supporting hundreds or even more connected devices.

To clarify, Soroush Araei, a PhD candidate at MIT in electrical engineering and computer science, explains that adopting IoT-over-5G doesn’t mean each device will require its own phone number.

“The main goal here is that you have a single radio receiver that can be reused for different applications,” Araei says. “You have a single piece of hardware which is flexible, and you can tune it across a wide frequency range in software.”

Using 5G standards, rather than simply utilizing 5G wireless networks, enables IoT devices to perform frequency hopping, conserve battery power, and employ massive-connectivity techniques allowing for up to one million devices per square kilometer.

How to Make a 5G IoT Chip

The slow adoption of 5G by IoT developers highlights the complexity of the hardware challenges involved.

“For IoT, power efficiency is critical,” says Eric Klumperink, associate professor of IC design at the University of Twente in Enschede, Netherlands. “You want a decent radio performance for very low power—[using] a small battery or even energy harvesting.”

As the number of devices connected to networks increases, whether 5G or otherwise, interference becomes a significant concern.

“In a world increasingly saturated with wireless signals, interference is a major problem,” says Vito Giannini, a technical fellow at Austin, Tex.-based L&T Semiconductor Technologies. (Neither Giannini nor Klumperink were involved with the MIT group’s research.)

Araei explains that utilizing 5G standards can potentially solve both issues. The MIT group’s technology employs a streamlined version of 5G designed for IoT and other applications, known as 5G reduced capacity (or 5G RedCap).

“5G RedCap IoT receivers can hop across frequencies,” he says. “But they’re not required to be as low-latency as the top-tier 5G applications [including smartphones].”

In contrast, the most basic IoT chip using Wi-Fi relies on a single frequency band, such as 2.5 or 5 gigahertz, and is susceptible to congestion if too many devices use the same channel.

Frequency hopping demands sophisticated radio communications hardware capable of quickly switching between frequency channels according to network instructions and then ensuring the frequency hops align with network instructions and timing.

This complexity requires a lot of hardware and software intelligence packed into a tiny chip, potentially one of hundreds attached to pallets in a warehouse.

But these features are just the beginning, Araei explains.

The core of a 5G RedCap chip lies in its ability to operate flexibly across a range of frequencies while maintaining a low power budget and reasonable overall cost. (The MIT group’s technology is currently only for receiving signals; separate components are required for transmitting across similar frequencies.)

The researchers employed techniques from analog circuits and power electronics, integrating them into an on-chip system to efficiently miniaturize RF frequency hopping. The team presented their findings at the IEEE Radio Frequency Integrated Circuits Symposium in San Francisco last month.

“This is kind of a switched-capacitor network,” Araei says. “You’re turning on and off these capacitors in a periodic manner sequentially, which is called ‘N-path structure.’ That generally gives you a low-pass filter.”

Instead of using a single capacitor, the team employed a miniaturized bank of capacitors, switching them on and off in tune with the needs of the received frequency range.

By placing this frequency-filtering capability at the front-end of the circuit, before the amplifier, the team achieved high efficiency in blocking interference. They report that their circuit filters out 30 times more interference compared to conventional IoT receivers while consuming only single-digit milliwatts of power.

In summary, the team has designed highly efficient, low-power 5G IoT receiver circuitry. The challenge now lies in designing a similarly effective transmitter.

Developing both would be a significant step towards commercial viability, according to Klumperink. “There are arguments to be made for IoT-over-5G (or 6G),” he says. “Because spectrum is allocated and managed better than ad hoc Wi-Fi connections.”

  Running the Internet of Things over 5G realistically means operating with very low power requirements. The MIT team’s chip consumes less than a milliwatt while still filtering out extraneous signals.Soroush Araei

Is This the Stuff of 5G IoT Chips to Come?

Klumperink believes the MIT group’s circuitry is feasible to manufacture using standard chip fabrication methods.

“I don’t see big hurdles as the circuit is implemented in mainstream CMOS technology,” Klumperink says. (The circuits require only a 22-nanometer fabrication process, making it accessible to a broad range of foundry facilities.)

Araei states that the team’s next objective is to eliminate the need for a battery or dedicated power supply.

“Is it possible to get rid of that power supply and basically harness the power from the existing electromagnetic waves in the environment?” Araei asks.

They also aim to expand the frequency range of their receiver technology to encompass the full spectrum of 5G signals. “In this prototype we were able to achieve low frequencies of 250 megahertz up to 3 GHz,” he says. “So is it possible to extend that frequency range let’s say up to 6 GHz, to cover the entire 5G range?”

If these challenges can be overcome, Giannini suggests that numerous applications could soon emerge. “It offers an advantage for mobility, scalability, and secure wide-area coverage in mid-range and mid-bandwidth scenarios,” he says of the MIT group’s research. He adds that the new circuit’s 5G IoT adaptability makes it suitable for applications such as “industrial sensors, some wearables, and smart cameras.”