You can't shout and hear the other guy, at the same time. And if two people in a conversation are both shouting, nobody can make out a thing. No, we are not talking about the nightly verbal mara-mari on some primetime Indian TV news channels we won't name.
This is problem that telecommunications people have lived with for 150 years. The conventional wisdom is: "It is generally not possible for a radio to receive and transmit on the same frequency band, because of the interference that results.” That is why, on mobile phones or with large communication transceivers, you need two separate frequencies, one to transmit, another to receive -- which is inefficient.
Last week, the spotlight was on a young Indian researcher in the US, an alumnus of IIT Kanpur and Stanford University, whose work might change decades-old assumptions which say full duplex or two way radio communications need two channels frequencies.
Ichalkaranji (Maharashtra)-born Dinesh Bharadia, 28, now at MIT, has been named winner of the Marconi Society's Young ScholarAward 2016, for his work that drastically improves efficiency by sending and receiving on the same channel. How does he do it? By cancelling the self-interference -- the electrical equivalent of nullifying the sound of your own shout, to make out what the other person is saying.
His PhD guide Prof Sachin Katti, who founded a California startup -- Kumu Networks -- where Dinesh worked to turn their theory into practice, sees huge potential: "Dinesh’s work enables a whole host of new applications, from extremely low-power Internet of Things connectivity to motion tracking. It has the potential for important future applications: wireless imaging that can enable driverless cars in severe weather, help blind people to navigate indoors, and much more.”
Dinesh sees his work making a difference in India, where mobile cell towers are thinly spread leading to those notorious call drops: "This technology can be used to build cheap and efficient full-duplex relays which can listen to signal from the mobile tower and transmit it at the same. By deploying these relays, we can save on expensive cellular tower infrastructure."
The challenge is to shrink his hardware till it fits on a mobile phone. Hopefully full duplex radio will soon let us talk and listen, easier, clearer -- and cheaper.