Researchers at the Indian Institute of Technology Mandi are working towards developing efficient remote powering and communication technology for futuristic internet of things (IoT) applications. The study was led by Dr. Siddhartha Sarma, Assistant Professor, School of Computing and Electrical Engineering, IIT Mandi, and co-authored by his student.

Highlighting his research, Shivam Gujral, Ph.D. scholar, School of Computing and Electrical Engineering, IIT Mandi, said, “We have developed a cooperative model, in which, backscatter communication and radiofrequency energy harvesting (RF-EH) devices act together to optimally allocate the resources such as time and antenna weights.”

The team performed research on two such powering options – radio frequency energy harvesting (RF-EH) and backscatter communication. In RF-EH, energy is transmitted by a dedicated transmitter to the IoT device through radio waves, the same kind of waves that are used in mobile phones for communication. In backscatter communication, as before, power is transmitted via radio waves, but with/without the need for a dedicated transmitter. Instead, RF signals available in the vicinity, such as Wi-Fi, cell phone signals, etc. are harnessed through reflection and backscatter to power the IoT objects.

The RF-EH and backscatter devices have their own strengths and drawbacks. For example, while the latter is associated with considerable energy savings compared to the former, it suffers from reduced data rate and a shorter transmission range. The IIT Mandi team has leveraged the complementary nature of these two technologies and judiciously combined them to achieve the desired Quality of Service (QoS) and efficiency using the power allotted to the system.

Commenting on the technical aspects of this work, Siddhartha Sarma, Assistant Professor, IIT Mandi, mentioned, “We used a dedicated power transmitter for the two devices, in which the backscatter device transferred information through a monostatic configuration and the RFEH device through the HTT protocol. The team used extensive numerical simulations to establish the superiority of the proposed cooperative scheme over existing schemes. In these simulations, key parameters were varied to analyse the performance of the model.”

Researchers plan to implement the joint radiofrequency energy harvesting backscatter communication system in real-time to analyse system performance. This would include working on the hardware aspects of the two complementary technologies. The potential of the proposed system is vast and includes, in addition to IoT devices, applications such as battery-free wireless cameras, wireless monitors, sensors, skin-attachable sensing platforms, contact lenses, machine-to-machine communication, and human-to-machine interactions.