With an explosion of billions of IoT devices, designers must worry more than ever about energy efficiency across wireless networks that serve a broad array of industrial and commercial settings.
One approach proposed by researchers at the IoT Research Lab at Santa Clara University calls for an enhanced Wi-Fi access point (AP) called Wiotap (Wi-Fi IoT AP). It produces a downlink packet scheduling mechanism which can assign a higher priority to IoT traffic verses regular traffic.
The Wiotap AP relies on an algorithm that uses a principle called least-laxity first (LLF) to assign priorities based on how long it takes destination devices to wake-up to receive a signal.
Researchers created a testbed of their concept with four IoT stations and regular traffic in both edge and cloud setups. For the edge scenario, they found an average 18% reduction in energy with a 36% reduction in delay. For the cloud, they found an average 13% energy reduction and an 18% reduction in delay.
Of course, for every IoT design scenario, engineers will make tradeoffs in which wireless network delay may be more important than energy loss (and other factors), or vice versa. But the Wiotap concept shows how a succession of researchers are grappling with ways to conserve energy with IoT alongside quality of service.
“Experts in industry and academia agree that the quality of service in dense wireless systems is going to be a primary concern in the near future,” said one of the Santa Clara researchers, Jaykumar Sheth, a Ph.D. candidate there.
Quality of service usually means network reliability, but engineers are beginning to evaluate power consumption with greater intensity. The power-sucking potential for IoT devices has gotten worse in recent years, especially for devices in applications such as security cameras or smart speakers that function in higher communication rates, Sheth said via an email to Fierce Electronics.
“Fortunately, several manufacturers and developers have started to acknowledge that power-inefficiency in IoT devices is a real concern,” Sheth added. “Thus, they are adopting newer power-saving techniques. However, some of these mechanisms impact the quality of service as well.”
“The bigger problem is how to make IoT devices more efficient both in terms of energy efficiency as well as quality of service,” he added.
Sheth and fellow researcher Behnam Dezfouli first introduced Wiotap in July 2019 in the IEEE IoT Journal. The research was partially supported by Cypress Semiconductor, which was purchased by Infineon in mid-2019 .
The researchers are working with Cypress/Infineon engineers on testing and further enhancing Wiotap, which could be included in future products, Sheth said.
Sheth noted that while the Wiotap research focused on IoT communications, there is currently no precise dictionary definition of what constitutes IoT devices. “There is a very thin line between regular devices and IoT devices,” he said. Smartphones can or cannot be considered as IoT devices based on the applications on hand, for example.
“The goal of Wiotap is to improve the quality of service for IoT devices that co-exist and function around regular wireless devices,” he said. Wiotap also does not require a modification to Wi-Fi standards.
Editor’s Note: Jaykumar Sheth will present a keynote, “Enhancing the energy-efficiency and timeliness of IoT communication in Wi-Fi networks” at 2 p.m. ET on Tuesday February 16 as part of Low Power Technologies Summit, a free virtual event on Feb.16-17 He will join a panel of experts afterwards. Register here to attend.