Ultra-Efficient 5G Chip for IoT Devices

The bandwidth and speed of modern 5G cellular networks provides Internet of Things (IoT) devices with a practical way to transfer large amounts of data to a central location. And importantly, it does this without any reliance on short-range wireless networks, such as Wi-Fi networks. As such, IoT devices communicating via 5G networks can be distributed over large geographical areas to collect data, track assets, monitor environmental conditions, or whatever else is required of them.

But while 5G offers the performance and accessibility that these devices need, this technology is not always well-suited for use in resource-constrained devices with tight energy budgets. 5G receivers, and their supporting hardware like filters and amplifiers, can be too complex and energy hungry for use in many IoT applications. But a team of researchers at MIT is working to do away with these present constraints so that 5G can be leveraged by a wider range of devices. They have developed a new, low-power receiver chip that requires little more than a few capacitors for operation.

Just sprinkle in some capacitors

The new chip is not only compact and cost-effective, but also highly resilient to signal interference. In fact, it is about 30 times more resistant to harmonic interference than some conventional wireless receivers. That is a significant advantage for IoT devices operating in crowded radio environments, like those found in factories or urban centers.

The system is built around a passive filtering mechanism that protects the receiver’s amplifier from jamming signals, all while consuming less than a milliwatt of static power. Instead of relying on large, energy-intensive external filters, the team utilized a network of precharged, stacked capacitors connected by tiny, power-efficient switches. This configuration allows the receiver to tune across a wide range of frequencies without the bulky footprint or high energy cost of traditional designs.

The researchers further enhanced the receiver’s performance by exploiting a phenomenon known as the Miller effect. By integrating their capacitor network into the amplifier’s feedback path, they made small capacitors behave like much larger ones, effectively shrinking the circuit without compromising performance. The entire active area of the receiver is smaller than 0.05 square millimeters.

5G for everyone

To be practical across the board in IoT devices, the receiver would need to be capable of operating reliably at very low voltages. To address this need, the researchers implemented a technique called bootstrap clocking. This boosts the control voltage just enough to keep the switches operating dependably, without requiring a full-blown power boost circuit, saving space and power in the process.

Looking forward, the researchers aim to make the chip even more performant. They are exploring methods to harvest energy from ambient signals like Wi-Fi or Bluetooth, which would allow future versions of the receiver to operate without a dedicated power supply. With these updates, they envision their technology being used in everything from health wearables and industrial sensors to smart cameras and environmental monitoring equipment.