By Dr. Mihai Sanduleanu
Imagine a world in which invisible sensors embedded in everyday objects, like refrigerators and light bulbs, and even in your own body, constantly collect, analyze and communicate data to each other, in real-time, to make our lives significantly more efficient.
While this might seem like a scene out of a science fiction film, it represents a not-so-distant reality, thanks to a system known as the “Internet of Things” (IoT).
The IoT aims to convert everything from household appliances and business products to virtually anything else in our surroundings into “smart” devices that are capable of transmitting and receiving data through internet-connected networks.
While IoT is on the brink of transforming our lives, one obstacle still remains: powering and connecting these smart devices is difficult, costly and impractical when using batteries and wires.
Smart devices will have tiny sensors, which must be able to receive and transmit data while blending into their surroundings. This implies that the antennas required to receive and transmit data must be tiny, posing a significant challenge to efficient data transfer between devices. An additional challenge to creating such tiny sensors and data transmission means is the issue of powering them.
To overcome both of these difficulties, I am working with a team of researchers at Masdar Institute, which include MSc student Badreyya AlShehhi and PhD student Ademola Mustapha, to develop a wireless transceiver smaller than the size of a fingernail that requires relatively little power and can be integrated directly onto a sensor’s chip.
In order for these tiny wireless transceivers to send and receive data, they will transmit on the 120 gigahertz (GHz) radio spectrum. At this very high frequency radio band, greater amounts of data can be sent with very small antennas, enabling the transceiver to be significantly smaller.
An additional advantage to using the 120 GHz radio band is that it is much less crowded than the heavily used 2.4 GHz and 5 GHz radio bands, which are the frequencies internationally designated for industrial, scientific and medical use. These frequencies are used by most wireless devices, including cordless phones, Wi-Fi routers and Bluetooth.
As millions of wireless devices compete for a slice of the 2.4 GHz and 5 GHz radio bands, expensive components (e.g. Crystals) must be installed on the devices to improve their frequency accuracy and transmission capabilities, increasing the device’s financial cost and physical footprint.
By leveraging the uncrowded 120 GHz radio band and a minimalist design approach, we can create wireless sensors that virtually disappear into the environment and utilize less power.
Because 120GHz radio signals do not penetrate well through walls, the sensors will have a smaller effective range and thus be best suited for connections within a single room, known as near-field IoT.
At 120 GHz, our transceiver can achieve very low energy-per-bit (the amount of energy required to send one bit of data) and through a minimalist design approach, our transceiver can achieve a low instantaneous power consumption; our receiver consumes only 100 micro-Watts of power while our transmitter consumes 500 micro-Watts (one micro-Watt is equivalent to one millionth of a Watt). This power consumption level is 30 times better than conventional transceivers operating at the 60 GHz frequency with very low energy-per-bit. Low instantaneous power is conducive to small battery size while low energy-per-bit increases the battery lifetime and both are important for near-field IoT.
In fact, the power requirement will be so low that the device may be able to be powered by tiny batteries, or organic photovoltaics cells, or it might be able to scavenge the electromagnetic energy from the environment, and thus contain no battery at all.
Utilizing a “Master-Slave” network – which is a network of sensor nodes connected to a master device that is integrated into the mains-powered Wi-Fi router – data is sent to each sensor node and back from the master device. Through the master-slave network, the tiny, ultra-low powered sensors will communicate wirelessly with the master device, which will then pass that data on to a person or machine anywhere in the world. This technology makes IoT low-cost and easily feasible anywhere at any time.
Creating an energy-efficient way to connect thousands of tiny sensors wirelessly is key to the development of IoT technologies, which by 2025, is a system that is estimated to be worth as much as US$6.2 trillion. With such critical advances in transceiver technology, IoT may soon be able to fulfill its promise of making our homes, business, cities and lives smarter and more efficient.
Dr. Mihai Sanduleanu is an Associate Professor of Electrical Engineering and Computer Science at the Masdar Institute of Science and Technology
12 May 2016