The Internet of Things has seen many millions, if not billions, of devices connected to the internet and this sudden surge of data has also given rise to more advanced technologies such as AI. While the function of IoT devices can drastically vary from temperature sensors to automatic door openers, they often have two things in common: they almost always use Wi-Fi and many require mounting in a remote location.
The issues of Wi-Fi and the need for remote installation are typically not problematic individually—but when a battery-powered device requires the use of Wi-Fi, designers are suddenly faced with a very difficult problem: power.
In this article, we'll take a look at a company that wants to make RF circuitry more compatible with digital processing by moving away from traditional analog designs.
The PolaRFusion logo. Image from InnoPhase
Analog vs. Digital Implementation of RF
InnoPhase is a San Diego-based RF technology company that started back in 2012 and was founded by Dr. Yang Xu (current CEO and CTO) and Dr. Dahong Qian.
They believe they've identified a serious issue with RF circuitry.
The company asserts that IQ analog circuitry on modern SoCs is taking up as much as 60% of the die area and consuming up to 68% of the power.
Image from InnoPhase
Traditional radio circuitry is largely analog, which requires various functional blocks (e.g., filters, data converters, and multipliers) to be implemented in hardware.
According to InnoPhase, "The most critical issue holding back market development and growth of battery-based IoT solutions is the significant amount of power required by today’s “old-technology” radio architectures."
So how do they propose to address this issue?
InnoPhase's differentiator in their proprietary architecture is that their RF waveform is encoded and decoded using polar coordinates. These radio signals can now be processed using software algorithms. Entire portions of the hardware that used to be implemented as analog circuitry can now be implemented as digital circuitry.
InnoPhase PolaRFusion: Reducing RF Power Consumption
The company has designed an architecture—PolaRFusion—that dramatically reduces power consumption, moves most of the RF circuitry away from the analog realm and runs protocols in software, not hardware circuits.
The technology can be thought of as software-defined radio that replaces up to 70% of analog circuitry with digital circuitry. These units include digital PA, digital controlled oscillator, time to digital converter, injection-locked oscillator, and hardware multipliers.
The image below shows the difference between a classical RF architecture and the PolaRFusion RF module where pink areas indicate analog circuitry. Note that the only analog circuitry in the PolaRFusion system is in the flex LNA and the ADC.
Image from InnoPhase
According to InnoPhase, by shifting analog processing into the non-linear domain, digital technology can be heavily exploited which allows for reduced die sizes to also produce smaller RF processing circuitry.
But the shift into the digital field also results in drastically reduced power consumption with the PolaRFusion architecture cutting power consumption by as much as eight times such that battery-powered Wi-Fi devices can last months instead of weeks.
The digital-controlled nature of the RF circuitry also gives rise to software control whereby different protocols can be defined so a device could hop between Wi-Fi, Bluetooth, and Zigbee without the need for any hardware change.
AAC Interview with InnoPhase
To learn more about InnoPhase, AAC's Bridgette Stone asked some questions with InnoPhase's VP Sales and Marketing, Tom Lee:
All About Circuits (AAC): Why hasn’t RF technology changed in 25 years?
Tom Lee (TL): A lot of it has been that digital electronics have not been fast enough to process radio signals. It would take many digital gates which is expensive so what we have done is develop a very specialized digital processor which is optimized for nonlinear mathematics. This is a revolutionary idea and no one else on the market has done anything like this. The other real benefit to shifting from the analog to the digital domain is that in the digital domain you can start manipulating signals in software. Our radio has hundreds of little knobs which can be used to change parameters.
AAC: Where do you see the PolaRFusion technology being used?
TL: Where we see the technology being used is in battery-based, edge-of-the-network devices. We decided to tackle wi-fi first as wi-fi is considerably more power-hungry than Bluetooth.
AAC: Is PolaRFusion technology being used in the real world now?
TL: To date, we have a company in Florida which is developing a security camera that can be mounted in a remote location such as a tree but you would not want a cable going up to it. So the idea is to use the InnoPhase technology to get a wireless security camera to run off a cell phone battery for a year without need to be charged.
AAC: What protocols can be used with InnoPhase?
TL: We have optimized the first chip to run Wi-Fi and Bluetooth, but later versions will also be able to run Zigbee. The technology could also be applied to other radio protocols such as LTE and NB-IoT.
The Future of Low-Power IoT
InnoPhase believes that their PolaRFusion architecture could change design for low-powered IoT devices that need to rely on battery power. Instead of batteries needing to be changed frequently or having to run powerlines to remote locations, devices could be set up and forgotten for long periods of time.
But the advantage of lower-power communications goes beyond IoT; it touches every environment involving remote wireless devices. Applications that would benefit from low-power radio communication would include wearables, medical monitoring, environment monitors, remote-controlled drones, and many other everyday devices.
Any RF engineers in the crowd who have expertise to share regarding these concepts? Start a conversation in the comments below.