Junior Digest

A 28-year-old Indian-origin MIT scientist has won a prestigious award for his research on radio waves, solving a problem that had stumped scientists for almost 150 years and enabling a host of new applications from Internet of Things connectivity to motion tracking.

Dinesh Bharadia, a graduate of Indian Institute of Technology (IIT) Kanpur, was honoured with the 2016 Marconi Society Paul Baran Young Scholar Award that carries a cash prize of $ 4,000.

Bharadia’s research disproved a long-held assumption that it is “generally not possible for a radio to receive and transmit on the same frequency band because of the interference that results.”

His work culminated in making full-duplex radios a reality through the development of effective self interference cancellation technology. Bharadia, who pursued his PhD from Stanford University in the US, will receive the award in November in California.

“Let’s say you are shouting at someone and they are shouting at you. Neither of you can hear the other, because you are both shouting in the same frequency,” said Bharadia, currently a researcher at Massachusetts Institute of Technology (MIT) in the US.

“The noise in your ears (interference) from your own shout prevents you from hearing the other person. That’s a good analogy for why radios have needed to use two different frequencies to transmit and receive simultaneously,” he said.

“It’s also why solving the challenge of developing ‘full duplex radios’ effectively doubles the amount of available spectrum,” Bharadia said.

The problem is more difficult than it sounds, said Bharadia. First, the interference is extremely strong – nearly a hundred billion times stronger than the signal that the radio might be trying to receive.

The resulting interference depends on the environment and its reflectors, changing in real-time as people move around. Typical radios (eg Wi-Fi) span many frequencies and use multi-antenna systems. Bharadia was able to demonstrate systems that overcame all these obstacles.

He turned full-duplex radios into a commercial reality by inventing new formulas that could in real-time, model the non-linear, time-varying self-interference as well as analog and digital self-interference cancellation circuits to apply the model to the known transmitted signal and cancel the self-interference.

The analogue cancellation filter Bharadia developed, also unleashed the potential for many more applications. The unique architecture had to allow cancellation in all environments.

“Dinesh’s work enables a whole host of new applications, from extremely low-power Internet of Things connectivity to motion tracking,” said Sachin Katti, Bharadia’s PhD advisor at Stanford.

“It has the potential to be used for important future applications such as building novel wireless imaging that can enable driverless cars in severe weather scenarios, help blind people to navigate indoors, and much more,” Katti said.

Taking us one step closer to internet-connected wireless implanted devices, a team of Indian-origin engineers has introduced a new way of communication that allows devices to talk to smartphones and watches.

Such devices include brain implants, contact lenses, credit cards and smaller wearable electronics.

This new “interscatter communication” developed by the team from University of Washington in Seattle works by converting Bluetooth signals into Wi-Fi transmissions over the air.

Using only reflections, an interscatter device such as a smart contact lens converts Bluetooth signals from a smartwatch, for example, into Wi-Fi transmissions that can be picked up by a smartphone.

“Wireless connectivity for implanted devices can transform how we manage chronic diseases,” said co-author Vikram Iyer, electrical engineering doctoral student.

“For example, a contact lens could monitor a diabetics blood sugar level in tears and send notifications to the phone when the blood sugar level goes down,” Iyer said.

Due to their size and location within the body, these smart contact lenses are too constrained by power demands to send data using conventional wireless transmissions.

The team demonstrated for the first time that these types of power-limited devices can “talk” to others using standard Wi-Fi communication.

Their system requires no specialised equipment, relying solely on mobile devices commonly found with users to generate Wi-Fi signals using 10,000 times less energy than conventional methods.

“Instead of generating Wi-Fi signals on your own, our technology creates Wi-Fi by using Bluetooth transmissions from nearby mobile devices such as smartwatches,” said study co-author Vamsi Talla.

The team’s process relies on a communication technique called backscatter, which allows devices to exchange information simply by reflecting existing signals.

Because the new technique enables inter-technology communication by using Bluetooth signals to create Wi-Fi transmissions, the team calls it “interscattering.”

Interscatter communication uses the Bluetooth, Wi-Fi or ZigBee radios embedded in common mobile devices like smartphones, watches, laptops, tablets and headsets, to serve as both sources and receivers for these reflected signals.

Bluetooth devices randomise data transmissions using a process called scrambling.

Beyond implanted devices, the researchers have also shown that their technology can apply to other applications such as smart credit cards.

This opens up possibilities for smart credit cards that can communicate directly with other cards and enable applications where users can split the bill by just tapping their credit cards together.

The new technique is described in a paper to be presented at the annual conference of the Association for Computing Machinery’s Special Interest Group on Data Communication (SIGCOMM 2016) in Brazil on August 22.

Scientists have discovered a ‘ghost snake’ – a new species of elusive, pale grey reptiles dwelling in Madagascar.

The researchers from the Louisiana State University (LSU) Museum of Natural Science , the American Museum of Natural History in the US and the Universite de Mahajunga in Madagascar studied the snake’s physical characteristics and genetics, which verified that it is a new species.

They named it Madagascarophis lolo – which means ghost in Malagasy.

The ghost snake, discovered at the Ankarana National Park in Madagascar, is part of a common group of snakes called Madagascarophis, or cat-eyed snakes, named for their vertical pupils, which is often found among snakes that are active in the evening or night.

Many of the cat-eyed snakes are found in developed areas or degraded forests. However, the researchers found the ghost snake on pale grey limestone rocks.

“None of the other snakes in Madagascarophis are as pale and none of them have this distinct pattern,” said Sara Ruane, post-doctoral researcher at the LSU Museum of Natural Science.

The researchers found that the ghost snake’s next closest relative is a snake called Madagascarophis fuchsi, which was discovered at a site about 100 kilometres north of Ankarana years ago. Both were found in rocky, isolated areas.

“I think what’s exciting and important about this work is even though the cat-eyed snakes could be considered one of the most common groups of snakes in Madagascar, there are still new species we don’t know about because a lot of regions are hard to get to and poorly explored,” Ruane said.

Researchers conduct their fieldwork during the rainy season in Madagascar when snakes and their prey, such as frogs, lizards and even other snakes, are most active.

The findings were published in the journal Copeia.

The Indian Space Research Organisation (Isro) launched on Thursday the INSAT-3DR, an advanced weather satellite that will provide a variety of meteorological services.

The satellite was launched using GSLV-F05 from the Sriharikota spaceport in Andhra Pradesh, in the tenth flight of India’s Geosynchronous Satellite Launch Vehicle (GSLV). The rocket is 49.1 metres tall and weighed 415.2 tonnes.

Isro is focusing on the cryogenic engine technology to save foreign exchange by launching heavier satellites on its own. It relies on the European Space Agency’s Ariane rocket to launch its heavy communication satellites.