Two Radios Are A Must for IoT Sensors to Boost Efficiency
Wed, April 14, 2021

Two Radios Are A Must for IoT Sensors to Boost Efficiency

UC San Diego's X Band device will enable a variety of IoT applications / Photo Credit: metamorworks (via Shutterstock)


Patrick Nelson of network news platform Network World reports that many people believe that inefficiencies in powering up sensors and radios have to be eliminated in order for IoT to become ubiquitous. Battery chemistry is simply not good enough. For example, it’s too expensive to perform truck-rolls whenever batteries need to be replaced. Solar battery-top-ups are not the solution either, as they are not suitable for mobile or impromptu ad hoc networks. 

Individuals are trying to find better chemistries that enable batteries to last longer or even find more efficient chips and electronics “that just sip electricity.” Universities are following a train of thought to wake-up network radios only when the devices need to send data. Presently, they are making progress in this area. Patrick Mercier, a professor of electrical and computer engineering at the University of California, San Diego, said that these existing devices do not know when to synchronize with the network. Hence, they periodically wake up even if there’s nothing to communicate, quoted Liezel Labios of university news website UC San Diego News Center. 

“By adding a wake-up receiver, we could improve the battery life of small IoT devices from months to years,” Mercier added. Wake-up receivers should be implemented at very high frequencies to make them useful. Every component gets smaller “the higher in spectrum one goes.” The university’s solution is at 9 GHz, in X Band. The device functions using “specific radio signals,” also known as a wake-up signature, directing them to an IoT sensor’s dedicated wake-up receiver chip. 

That radio consumes less energy than the data radio chip since its sole purpose is to “listen for the wake-up signature.” Meanwhile, a more power-consuming radio performs more heavy-duty tasks such as sending data, although the device is switched on by the wake-up radio if necessary. UC San Diego said that its X Band device is usable in “varied ambient temperatures” from 14 F to 104 F. It also stated that the device has a sensitivity of -69.5 dBm. Although the device has a delay of 540 ms, the figure does not pose problems for IoT use.

Given the X Band’s temperature robustness and low power consumption, Mercier argued that the device “will enable all sorts of new IoT applications.”